JN0-360 juniper - GRATIS EXAM · Whenever switch updates an entry in the MAC address table, the switch resets the timer for that entry. Timers are used in aging process of old entries

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JN0-360 juniper

Number: JN0-360Passing Score: 800Time Limit: 120 min


Sections1. STP2. MPLS3. Protocol Independant Routing4. OSPF5. ISIS6. BGP7. Layer 2 Switching VLAN's8. IPv69. Tunnels10.High Availability


STP

QUESTION 1Which two statements are true about virtual switches? (Choose two.)


A. Multiple virtual switches share a single MAC table.B. Virtual switches contain separate MAC tables.C. By default, the direct route associated with a virtual switch's IRB interface is placed in inet.0.D. By default, the direct route associated with a virtual switch's IRB interface is placed in the associated virtual switch's routing table.

Correct Answer: BCSection: STPExplanation

Explanation/Reference:Explanation:

In a Virtual Chassis, multiple switches—each with its own set of interfaces with unique MAC addresses—are connected together to form one chassis that can bemanaged as a single switch. The MAC address assigned to each network-facing interface on the switch changes when the switch joins a Virtual Chassis. Becauseall Layer 2 traffic decisions are based on an interface’s MAC address, understanding MAC address assignment is important to understanding how network traffic isforwarded and received by the Virtual Chassis. For additional information about how a network uses MAC addresses to forward and receive traffic, seeUnderstanding Bridging and VLANs on EX Series Switches.

http://www.juniper.net/documentation/en_US/junos15.1/topics/concept/virtual-chassis-mac-address-assignment.html

QUESTION 2In Q-in-Q tunneling, what is the purpose of the pop-swap operation?

A. pop the outer tag and swap the inner tagB. pop and swap the inner tagC. pop and swap both outer and inner tagsD. pop the inner tag and swap the outer tag

Correct Answer: ASection: STP


Explanation


The transit route POP's the outer label and swaps the inner label

QUESTION 3What are three components of the tag portion of an 802.1Q-tagged Ethernet frame? (Choose three.)

A. Tag Protocol IdentifierB. maximum transmission unitC. canonical format indicatorD. unique VLAN identifierE. frame check sequence

Correct Answer: ACDSection: STPExplanation


The VLAN tag was invented to distinguish among different VLAN broadcast domains on a group of LAN switches. The VLAN tag is a two-byte field insertedbetween the source MAC address and the Ethertype (or length) field in an Ethernet frame. Another two-byte field, the Tag Protocol Identifier (TPI or TPID),precedes the VLAN tag field.

The Canonical Format Indicator (CFI) bit indicates whether the following 12 bits of VLAN identifier conform to Ethernet or not. For Ethernet frames, this bit is alwaysset to 0. (The other possible value, CFI=1, is used for Token Ring LANs, and tagged frames should never be bridged between an Ethernet and Token Ring LANregardless of the VLAN tag or MAC address.)

http://www.juniper.net/documentation/en_US/junos15.1/topics/concept/layer-2-networking-ethernet-frame-forwarding-802-1q-vlan-tag-mx-solutions.html

QUESTION 4Which three mechanisms are used by switches to build and maintain bridge tables? (Choose three.)

A. learningB. rewritingC. floodingD. aging


E. blocking

Correct Answer: ACDSection: STPExplanation


Learning:A switch begins learning the local MAC addresses as soon as it is connected to other devices or to a network. This learning capability makes switches easy to useon a network.

Flooding:As part of the learning process, a switch will flood the single frame out all of its other ports when it cannot find the destination MAC address in the switch’s lookuptable.

Aging:Whenever switch updates an entry in the MAC address table, the switch resets the timer for that entry. Timers are used in aging process of old entries. Aging helpsto remove old entries and free memory of MAC address table to add new entries.

QUESTION 5What is the purpose of a trunk link?

A. to carry traffic for multiple VLANs between multiple switchesB. to interconnect multiple bridging domains on the same switchC. to aggregate multiple native VLANs into a single bridging domainD. to allow Layer 3 functionality for multiple VLANs

Correct Answer: ASection: STPExplanation


A trunk is a line or link designed to handle many VLANs simultaneously, and that connects major switching centers or nodes in a communications system.

QUESTION 6What are two differences between RSTP and VSTP? (Choose two.)


A. Using VSTP, the BPDU destination address is always 01:00:0C:CC:CC:CD.B. Using VSTP, the BPDU frame carries an 802.1Q tag.C. Using RSTP, the BPDU destination address is always 01:00:0C:CC:CC:CD.D. Using RSTP, the BPDU frame carries an 802.1Q tag.

Correct Answer: ABSection: STPExplanation


VSTP on Juniper Networks routers has some interoperability with other proprietary per-VLAN vendor solutions; specifically, VSTP can interoperate with per-VLANspanning tree (PVST) and Rapid-PVST on IEEE 802.1Q non-proprietary trunks.

In PVST, the IEEE 802.1Q BPDUs are sent untagged on the common spanning-tree VLAN 1 for interoperability with other vendors. The CST BPDUs are sent tothe IEEE standard bridge group: MAC Address 01-80-c2-00-00-00, DSAP 42, SSAP 42.

PVST BPDUs are tagged and sent to MAC address 01-00-0c-cc-cc-cd (SNAP HDLC protocol type 0x010b) for each VLAN on a trunk. PVST per-VLAN BPDUs aretunneled by pure IEEE 802.1Q bridges.

QUESTION 7A rogue switch has been added to your network, exchanged BPDUs, and is now part of the spanning tree topology.

Which feature would help prevent this from happening in the future?

A. storm controlB. BPDU controlC. root protectionD. loop protection

Correct Answer: BSection: STPExplanation


EX Series switches support spanning-tree protocols that prevent loops in a network by creating a tree topology (spanning-tree) of the entire bridged network. Allspanning-tree protocols use a special type of frame called bridge protocol data units (BPDUs) to communicate with each other.


When BPDUs generated by other devices are transmitted to switches on which spanning-tree protocols are configured, a misconfiguration can occur in thespanning tree and a network outage can occur. Therefore, it is necessary to protect an interface in a spanning-tree topology from BPDUs generated from otherdevices.

http://www.juniper.net/documentation/en_US/junos13.3/topics/task/configuration/spanning-trees-bpdu-block-cli.html

QUESTION 8What is the maximum number of MSTIs supported in an MST region?

A. 32B. 64C. 128D. 256



Multiple Spanning Tree Protocol (MSTP) was first specified in IEEE 802.1s and is standardized in IEEE 802.1Q. MSTP enables multiple VLANs to be mapped tothe same spanning-tree instance, reducing the number of spanning-tree instances needed to support a large number of VLANs. MSTP provides multiple forwardingpaths for data traffic and enables load balancing. It improves the fault tolerance of the network because a failure in one instance, or forwarding path, does not affectother instances.

MSTP has a backward compatibility mode in which it can fall back to STP or RSTP operation on links with bridges that support only STP or RSTP.

The maximum number of MSTP instances supported in Juniper Networks MX Series 3D Universal Edge Routers is 64.

https://www.juniper.net/documentation/en_US/junos12.3/topics/concept/mx-series-multiple-stp.html

QUESTION 9Which two statements are true about STP and RSTP? (Choose two.)

A. STP uses a proposal-and-agreement handshake on point-to-point links instead of timers.B. In RSTP, root ports and edge ports transition to the forwarding state immediately, without exchanging messages with other switches.C. In RSTP, a TCN is generated when a port transitions to the discarding state.D. In STP, the forwarding delay timer and maximum age timer define the convergence delay.


Correct Answer: BDSection: STPExplanation


Rapid Spanning Tree Protocol (RSTP–802.1w/802.1d 20 04): Similar to legacy STP, RSTP implements a single instance of Spanning Tree but dramatically improves the convergence time

For example, in legacy STP, a host port coming online can take up to 30 seconds (2 x FWD_Delay) before it begins forwarding . Direct or indirect node/link failureconvergence can even take up to 50 seconds (MAX_Age + 2 x FWD_Delay) with legacy STP. Such convergence times are not acceptable in today’s high-performance enterprise networks

RSTP overcomes slow convergence times by introducing new port roles (edge port, alternate port and backup port) and new convergence behavior under specificconnectivity conditions (for example, point-to-point or shared medium) . These enhancements enable RSTP to achieve sub-second forwarding and networkconvergence

RSTP is backward-compatible with legacy STP; if legacy STP BPDU is detected on a link, then an RSTP-capable bridge will revert to legacy STP on that given port.

Understanding RSTP for EX Series Switcheshttp://www.juniper.net/documentation/en_US/junos13.2/topics/concept/spanning-trees-ex-series-rstp-understanding.html

QUESTION 10What are two types of BPDUs in the Spanning Tree Protocol? (Choose two.)

A. configurationB. helloC. topology change notificationD. link state

Correct Answer: ACSection: STPExplanation


Bridge Protocol Data Units (BPDUs) are frames that contain information about the Spanning tree protocol (STP). Switches send BPDUs using a unique MAC


address from its origin port and a multicast address as destination MAC (01:80:C2:00:00:00, or 01:00:0C:CC:CC:CD for Per VLAN Spanning Tree). For STPalgorithms to function, the switches need to share information about themselves and their connections. What they share are bridge protocol data units (BPDUs).BPDUs are sent out as multicast frames to which only other layer 2 switches or bridges are listening.

There are three kinds of BPDUs:

Configuration BPDU, used by Spanning tree protocol to provide information to all switches. TCN (Topology Change Notification), tell about changes in the topology. TCA (Topology Change Acknowledgment), confirm the reception of the TCN.

https://en.wikipedia.org/wiki/Bridge_Protocol_Data_Unit

QUESTION 11-- Exhibit

Click the Exhibit button.

In the exhibit, all switches run STP; however, the link between bridge G and bridge E fails.

What does root bridge A do after it receives information about this link failure?


A. Root bridge A sets the acknowledge flag and sends an updated topology BPDU.B. Root bridge A sends a topology change notification BPDU.C. Root bridge A sets the topology change flag and sends an updated configuration BPDU.D. Root bridge A floods an updated BPDU topology database.

Correct Answer: CSection: STPExplanation


Topology Change and Topology Change Detection

When an 802.1D bridge detects a topology change, the bridge first notifies the root bridge using a reliable mechanism. Once the root bridge is aware of a change inthe topology of the network, the root bridge sets the topology change flag on the BPDUs sent out, which are then relayed to all the bridges in the network. When abridge receives a BPDU with the TC flag bit set, the bridge reduces its bridging-table aging time to forward delay seconds, which ensures a relatively quick flushingof stale information.

There are three kinds of BPDUs:

Configuration BPDU, used by Spanning tree protocol to provide information to all switches. TCN (Topology Change Notification), tell about changes in the topology. TCA (Topology Change Acknowledgment), confirm the reception of the TCN.

QUESTION 12Which two values displayed in the output from the "show spanning-tree MSTP configuration" command must match on all switches participating in the same MSTPregion? (Choose two)

A. root bridge identifierB. authentication checksumC. context identifierD. configuration digest

Correct Answer: CDSection: STPExplanation

Explanation/Reference:


Explanation:

MSTP allows switches to be logically grouped into manageable clusters, known as multiple spanning-tree (MST) regions. An MST region is a group of switches thatshare the same region name, revision level, and VLAN-to-instance mapping parameters. These values are used to generate the configuration digest for the MSTregion, which must match the configuration digest on all switches participating in the same MST region. The system-generated context identifier must also matchbetween switches participating in the same MST region

QUESTION 13You are asked to design a Layer 2 switched topology that can automatically recover from link failures.

Which type of protocol would you consider in your design?

A. GSTPB. LLDPC. LFMD. MSTP

Correct Answer: DSection: STPExplanation


The Multiple Spanning Tree Protocol (MSTP) is used to create multiple spanning-tree instances (MSTIs) within a Layer 2 network. Each MSTI creates separatetopology trees that can be administratively mapped to one or more VLANs.

QUESTION 14Click the Exhibit button


In an RSTP network, the root and designated ports have been elected as shown in the exhibit

What will be the port type of port 1?

A. backup portB. discarding portC. alternate portD. listening port



An alternate port is a switch port that has an alternate generally higher-cost-path to the root bridge. In the event that the root port fails, the alternate port assumesthe role of the root port and is placed in the forwarding state. Alternate ports are placed in the discarding state, but receive superior BPDUs from neighboringswitches. Alternate ports are found on switches participating in a shared LAN segment for which they are not functioning as the designated bridge.


QUESTION 15Which two elements contribute to the bridge ID when configuring RSTP? (Choose 2)

A. designated MAC addressB. bridge priorityC. extended system IDD. root IDE. bridge address

Correct Answer: BESection: STPExplanation


A unique 48-bit Universally Administered MAC Address, termed the Bridge Address, shall be assigned to each Bridge. The Bridge Address may be the individualMAC Address of a Bridge Port, in which case, use of the address of the lowest numbered Bridge Port (Port 1) is recommended.

The unique Bridge Identifier assigned to this Bridge, comprising two components—the Bridge Identifier Priority, which may be modified by management and is themore significant when Bridge Identifiers are compared, and a component derived from

Configuring the Rapid Spanning Tree Protocolhttp://www.juniper.net/techpubs/software/junos/junos95/swconfig-layer-2/conf-stp.html#conf- bridge-priority

QUESTION 16In an RSTP network, which combination of port types can exist on the root bridge?

A. There can be some combination of designated ports and backup portsB. There can be some combination of root ports and alternate portsC. All ports will be designated portsD. All ports will be root ports




On a root switch all ports will be designated ports

Port Roles in STP

This section describes the function of the port roles in STP. The use and implementation of port roles differs slightly between different versions of STP.

Port roles include:

Designated port—Responsible for forwarding the traffic coming from the spanning-tree root bridge onto this segment.Backup port—A backup for the designated port.Root port—The root port of a bridge is the port closest to the root bridge. It is responsible for carrying the traffic from this segment toward the root bridge, using theshortest path to reach the root.Alternate port—A backup for the root port.Master port (MSTP only)—The best possible path to reach the common internal spanning-tree (CIST) root bridge from any MSTP region.

http://www.juniper.net/techpubs/en_US/junos12.3/topics/reference/general/mx-series-stp-port-roles.html

QUESTION 17In the evaluation of an RSTP configuration BPDU, which two values are contained in the Bridge ID value? (Choose two)

A. root bridge addressB. priorityC. originating bridge addressD. port number



The bridge ID is a combination of a configurable priority value and the originating bridge address (a unique MAC address for the bridge). The lowest bridge IDdetermines the root, or designated bridge

QUESTION 18Which two configuration elements are defined under an MSTP instance? (Choose two)


A. revision-levelB. bridge-priorityC. mstp-levelD. vlan



Each MSTI can have different bridge priorities and VLANs assigned


Which two topologies shown in the exhibit would require the use of a spanning-tree protocol? (Choose two)

A. ringB. treeC. star


D. mesh

Correct Answer: ADSection: STPExplanation


Spanning-tree protocols are Layer 2 protocols that prevent loops and calculate the beset path through a switched network that contains redundant paths. Spanning-tree protocols are only necessary when redundant paths exist within a Layer 2 network

QUESTION 20An Ethernet bridge is configured such that all interfaces are in a single broadcast domain By default. Which two tasks does the bridge perform in response toreceiving a multicast frame? (Choose two)


A. It learns the source MAC addressB. It drops the frameC. It floods the frame out of all interfaces except the one on which it was receivedD. It floods the frame out of particular interfaces based on its multicast MAC table



A switch floods a frame out all of its other ports (Expect the port that it is received on) under the following circumstances:

If the frame is intended for an unknown unicast destinationIf a broadcast frame is received with a destination MAC address ff ff ff ff ff ff, the switch forwards the broadcast frame out all of the other ports. VLAN exceptions tothis rule are discussed later in this section.If a multicast frame is received, the switch forwards the multicast frame (the first byte contains an odd value such as 01 00 50 00 00 09) out all the switch’sremaining ports. VLAN exceptions apply to flooding by limiting it to the same VLAN as the sender.


The flooding process for broadcast is necessary for protocols such as ARP which maps an IP address to a MAC address via broadcasting. One significant problemwith this flooding process occurs when switches in a network are redundantly connected into physical loops. Flooding broadcast frames can cause a “broadcaststorm” on a network, causing it to fail.


ge-1/0/3 { vlan-tagging; unit 0 { family bridge { interface-mode trunk; vlan-id-list [ 100 200]; } }}

An interface is configured as shown in the exhibit.

What must also be configured for this interface to participate in VLAN 100 and 200?

A. broadcast domainsB. VLANsC. bridge domainsD. encapsulation type



The MX Series supports two methods of configuring bridge interfaces: enterprise and service provider style.

Service provider style requires explicit configuration of each feature on the interface, and the bridge domains need to reference the interface.

Enterprise style does not require explicit configuration for each feature, which reduces the amount of configuration but also reduces the number of features.

[MX] Interface Bridge Configuration: Enterprise vs Service Provider style https://kb.juniper.net/InfoCenter/index?page=content&id=KB27291&actp=RSS


QUESTION 22Which two configuration elements must match on all switches participating in the same MSTP region? (Choose two.)

A. MSTP versionB. configuration nameC. MSTI revision numberD. revision level



MSTP allows switches to be logically grouped into manageable clusters known as multiple spanning-tree (MST) regions. An MST region is a group of switches thatshare the same region, configuration name, revision level, and VLAN-to-instance mapping parameters.

QUESTION 23Click the Exhibit button.

Which two topologies shown in the exhibit could be implemented without a spanning-tree protocol? (Choose two.)

A. ringB. tree


C. starD. mesh



Spanning-tree protocols are Layer 2 protocols that prevent loops and calculate the beset path through a switched network that contains redundant paths. Spanning-tree protocols are only necessary when redundant paths exist within a Layer 2 network

QUESTION 24Which two values are used by an RSTP bridge to remove stale BPDU information? (Choose two.)

A. Message AgeB. Forwarding DelayC. Hello TimeD. Max Age



RSTP uses the message age value in conjunction with the max age value to indicate a communication failure and to determine when to flush the MAC table. Themessage age is the number of seconds elapsed since the most recent BPDU was received. The maximum age timer specifies the maximum expected arrival tie ofthe hello BPDU. If the maximum age timer expires, the bridge detects that the link to the root bridge has failed and initiates a topology reconvergence.

QUESTION 25You have recently configured MSTP on two EX Series switches in your network to participate in the same MSTP region. You issue the "show spanning-tree mstpconfiguration" command on both switches and notice that the configuration digests do not match. What does this mismatch indicate?

A. Everything is functioning as expected because the configuration digests should not match.B. You should ensure that the max-age and hello timers are equal on both switches.C. You should ensure that the bridge IDs and priority values are unique on both switches.D. You should ensure that the MSTIs and their VLAN IDs are equal on both switches.




MSTP allows switches to be logically grouped into manageable clusters, known as multiple spanning-tree (MST) regions. An MST region is a group of switches thatshare the same region name, revision level, and VLAN-to-instance mapping parameters. These values are used to generate the configuration digest for the MSTregion, which must match the configuration digest on all switches participating in the same MST region.


bridge-domains { vlan_100 { vlan-id 100; routing-interface irb.0; }}

user@switch> show interfaces terse irb*Interface Admin Link Proto Local Remoteirb up upirb.0 up down inet 1.1.1.254/24

Referring to the exhibit, what must be true of the vlan_100 bridge domain?

A. vlan_100 has at least one Ethernet interface assigned to it.B. vlan_100 does not have an Ethernet interface assigned to it.C. vlan_100 might have an active Ethernet interface assigned to it.D. vlan_100 does not have an active Ethernet interface assigned to it.




irb.0 is the logical instance (IFL) for this irb. From the above output you can see that the interface is administratively configured as up; however, it is physicallydown. Since the IFD irb shows as up up and the IFL irb.0 shows as up down this shows that a physical interface has not been assigned to irb.0 or the interfaceassigned to it isn't active

ifd Refers to a physical device ifl Refers to a logical device iff Refers to an address family ifa Refers to an address entry iif Refers to an incoming interface, either an ifd or an ifl (uses a kernel interface index, not an SNMP index)

https://kb.juniper.net/InfoCenter/index?page=content&id=KB2820&actp=search

QUESTION 27Which three elements contribute to the bridge ID when configuring RSTP? (Choose three.)

A. designated MAC addressB. priorityC. extended system IDD. root IDE. bridge address

Correct Answer: BCESection: STPExplanation


RSTP uses the bridge priority and unique bridge address similar to STP; RSTP also includes the extended system ID. Although priority and extended system ID areconfigured separately, RSTP evaluates a bridge's priority for the root and designated bridge election process by conatenating the two fields together into a singlevalue.

QUESTION 28Which three STP protection mechanisms are supported on MX Series, EX Series, and QFX Series devices? (Choose three.)

A. trunk protectionB. BPDU protectionC. loop protectionD. access protectionE. root protection




There is no such thing as trunk protection or access protection

QUESTION 29Your network runs RSTP and includes a LAN segment shared by two MX Series devices. The two MX Series devices sharing this LAN segment each have twoconnections on the shared segment.

Which two statements are true? (Choose two.)

A. The port on the selected MX Series device with the lowest port ID is selected as the designated port.B. The MX Series device with the highest-cost path to the root bridge is selected as a designated bridge for the shared segment.C. The port on the selected MX Series device with the highest port ID is selected as the designated port.D. The MX Series device with the least-cost path to the root bridge is selected as the designated bridge for the shared segment.



QUESTION 30Which two Layer 2 protocols are supported on MX Series devices? (Choose two.)

A. BGPB. RIPC. RSTPD. MSTP




Only RSTP and MSTP are Layer 2 protocols. BGP and RIP are Layer 3 protocols


[edit protocols mstp]user@switch1# showconfiguration-name mstp-region1;revision-level 1;interface ge-0/0/1;interface ge-0/0/2;interface ge-0/0/3;interface ge-0/0/4;interface ge-0/0/5;msti 1 { bridge-priority 4k; vlan 100 120;}msti 2 { bridge-priority 8k; vlan 150-160;}

[edit protocols mstp]user@switch2# showconfiguration-name mstp-region;revision-level 2;interface ge-0/0/1;interface ge-0/0/3;interface ge-0/0/4;interface ge-0/0/5;msti 1 { bridge-priority 8k; vlan 100-120;}msti 2 { bridge-priority 4k; vlan 150-160;


}

Switch 1 and Switch 2 are configured to run MSTP. However, MSTP is not working.

Referring to the exhibit, which two actions will correct the problem? (Choose two.)

A. Configure interface ge-0/0/2 on Switch 2B. Correct the bridge-priority parameter to be identical on both switches.C. Configure revision-level 2 on Switch 1.D. Correct the configuration-name parameter to be identical on both switches.



QUESTION 32What does an STP BPDU Port ID field contain?

A. bridge priorityB. bridge port priority and bridge port addressC. bridge priority and bridge addressD. port priority and port address



Port IDThis field contains a unique value for every port. This value is a combination of the outbound port's priority and a unique value to represent the port. The default portpriority is 128 for every interface on an MX Series 3D Universal Edge Router. The switch automatically generates the port number and you cannot configure it.

The Port ID contains two fields1.) Port Priority2.) Port Number


QUESTION 33For two switches to participate in the same Multiple Spanning Tree Protocol (MSTP) region, which three values must match? (Choose three.)

A. extended system IDB. region nameC. member VLAN ID listD. root bridge IDE. revision number



The following values must match on all MSTP switches participating in the same MSTP region1.) Region (configuration-name) Name2.) Configuration digest3.) Revision Number4.) MST VLAN-to-instance assignmen

QUESTION 34Which Operational mode command displays the root bridge ID for a Junos device

A. show spanning-tree root-idB. show spanning-tree bridgeC. show spanning-tree bridge-idD. show spanning-tree root



To display the local switches' view of the root bridge ID you should use the "show spanning-tree bridge" command. You can use the output to compare the localbridge ID and the root bridge ID to determine whether the local device is acting as the root bridge



In an RSTP network, the root and designated ports have been elected as shown in the exhibit. What will be the port type of Port 1?

A. backup portB. discarding portC. alternate portD. listening port

Correct Answer: ASection: STPExplanation


When a designated bridge has multiple ports connected to a shared LAN segment, it selects one of those ports as the designated port. The designated port istypically the port with the lower port ID. RSTP considers all other ports on the designated switch that connects to that same shared LAN segment as backup ports.


QUESTION 36A root bridge in an RSTP network is connect to other neighboring bridge using point-to-point links. Which combination of port types can exist on the root bridge?

A. A combination of designated ports and alternate portsB. A combination of root ports and alternate portsC. All ports are designated portsD. All ports are root ports



All RSTP ports on a root bridge will be in the designated port state unless there are redundant connections to the same network segment. When using point-to-point links, all ports connect to different network segments

QUESTION 37What are two ways to prevent Layer 2 loops in a network? (Choose two)

A. BPDU protectionB. LDP protectionC. loop protectionD. Layer 2 protection



It is good practice to enable BPDU protection on interfaces where no BPDUs are expected. If a protected interface receives BPDUs, the switch disables tineinterface and stops forwarding frames by transitioning to a blocking state. Blocking state ensures that an unexpected spanning-tree enabled device cannot beconnected to this port, which could cause an unexpected Layer 2 loop.

If a loop-protection-enabled interface stops receiving BPDUs from its designated port, it reacts as it would react to a problem with the physical connection on theinterface. It does not transition the interface to a forwarding state, wich can avoid potential Layer 2 loops.


QUESTION 38Which command enables STP on an MX Series device?

A. set protocols rstp force-mode stpB. set protocols rstp mode stpC. set protocols rstp version stpD. set protocols rstp force-version stp



There is no STP configuration hierarchy on Junos devices. To run STP you use force RSTP to operate in STP mode by using the "force-version stp" configurationoption at the [edit protocols rstp] hierarchy


Based on the designated values show in the exhibit, which three statements are true? (Choose three.)


A. Switch A will become the root bridgeB. Both interfaces on Switch B will be in the forwarding stateC. Switch C will become the root bridgeD. Both interfaces on Switch A will be in the forwarding stateE. Both interfaces on Switch C will be in the forwarding state



Switch C has the lowest bridge ID, so it will become the root bridge. All point-to-point interfaces on a root bridge will be assigned the port role of designated with aport state of forwarding. Switch B is elected the designed bridge because it has a lower bridge ID than Switch A, and its interface ge-0/0/1 is in the root port role andforwarding state due to lowest path cost to the root bridge.

QUESTION 40What are two characteristics of an interface that has been placed in the blocking state by STP? (Choose two.)

A. It drops all data frames

http://www.gratisexam.com/B. It listens to received BPDUsC. It uses learned MAC addresses to populate the MAC tableD. It forwards outbound data frames only

Correct Answer: ABSection: STPExplanation


An STP port in the blocking state will drop all data packets. The port will also listen for incoming BPDUs


MPLS

QUESTION 1Which statement is correct about the inet.3 routing table?


A. MPLS creates a copy of the mpls.0 table and stores it in the inet.3 routing table.B. The inet.3 routing table is used by transit routers to identify label values.C. BGP can use the inet.3 routing table to resolve next hops.D. MPLS uses the inet.3 routing table to assign labels.

Correct Answer: CSection: MPLSExplanation


The IGPs and BGP store their routing information in the inet.0 routing table, the main IP routing table. If the traffic-engineering bgp command is configured, therebyallowing only BGP to use MPLS paths for forwarding traffic, MPLS path information is stored in a separate routing table, inet.3. Only BGP accesses the inet.3routing table. BGP uses both inet.0 and inet.3 to resolve next-hop addresses. If the traffic-engineering bgp-igp command is configured, thereby allowing the IGPs touse MPLS paths for forwarding traffic, MPLS path information is stored in the inet.0 routing table.

http://www.juniper.net/documentation/en_US/junos12.3/topics/concept/mpls-routing-tables.html

QUESTION 2Which two statements are correct about default MPLS behavior on Junos devices? (Choose two.)

A. The MPLS label is popped by the penultimate router.B. The MPLS label is popped by the ultimate router.C. The MPLS label is pushed by the ingress router.D. The MPLS label is swapped by the ingress router.

Correct Answer: ACSection: MPLSExplanation



Penultimate hop popping (PHP) is a function performed by certain routers in an MPLS enabled network. It refers to the process whereby the outermost label of anMPLS tagged packet is removed by a Label Switch Router (LSR) before the packet is passed to an adjacent Label Edge Router (LER).

An "ingress router" is a Label Switch Router that is a starting point (source) for a given Label Switched Path (LSP). An ingress router may be an egress router or anintermediate router for any other LSP(s). Hence the role of ingress and egress routers is LSP specific. Usually, the MPLS label is attached with an IP packet at theingress router and removed at the egress router, whereas label swapping is performed on the intermediate routers.

QUESTION 3Which two statements regarding the MPLS label information base are correct? (Choose two.)

A. The MPLS label information base is stored in the inet.3 table.B. The MPLS label information base is stored in the mpls.0 table.C. The label information base is used by all LSRs to forward LSP traffic.D. The label information base is used by transit LSRs to forward LSP traffic.

Correct Answer: BDSection: MPLSExplanation


Labels represent the FEC along the LSP from the ingress node to the egress node. The label is prepended to the packet when the packet is forwarded to the nexthop. Each label is valid only between a pair of LSRs. A downstream LSR reached by a packet uses the label as an index into a table that contains both the next hopand a different label to prepend to the packet before forwarding. This table is usually referred to as a label information base (LIB).

LIB (Label Information Base) is the software table maintained by IP/MPLS capable routers to store the details of port and the corresponding MPLS router label to bepopped/pushed on incoming/outgoing MPLS packets. Entries are populated from label-distribution protocols. LIB functions in the control plane of routers MPLSlayer. It is used by the label distribution protocol for mapping the next hop labels

QUESTION 4Which two statements are correct about RSVP path messages? (Choose two.)

A. They are sent by the egress router upstream.B. They are sent by the ingress router downstream.C. They are used to create an LSP.


D. They are used to reserve resources for an LSP.

Correct Answer: BCSection: MPLSExplanation


Each sender host transmits path messages downstream along the routes provided by the unicast and multicast routing protocols. Path messages follow the exactpaths of application data, creating path states in the routers along the way, thus enabling routers to learn the previous-hop and next-hop node for the session. Pathmessages are sent periodically to refresh path states.

http://www.juniper.net/documentation/en_US/junos15.1/topics/concept/mpls-path-messages.html

QUESTION 5Which two statements are correct regarding LDP-signaled VPLS instances? (Choose two.)

A. You must enable the Layer 2 VPN signaling NLRI.B. You must configure the same VPLS identifier on all peers.C. You must define a the same site-identifier value on all peers.D. You must define all neighbors using their tunnel end-point IP addresses.



The VPLS-ID Identifies the virtual circuit identifier used for the VPLS routing instance or mesh group. This statement is a part of the configuration to enable LDPsignaling for VPLS.

For more details see:https://inetzero.com/vpls-some-simples-configurations/

QUESTION 6Which two statements are correct regarding LDP-signaled Layer 2 circuits? (Choose two.)

A. You must enable the Layer 2 VPN signaling NLRI.


B. You must configure the virtual circuit identifier.C. You must specify the neighbor using the tunnel end-point IP address.D. You must define a unique site-identifier value.



The VPLS-ID Identifies the virtual circuit identifier used for the VPLS routing instance or mesh group. This statement is a part of the configuration to enable LDPsignaling for VPLS.

For more details see:https://inetzero.com/vpls-some-simples-configurations/

QUESTION 7Which two statements are correct regarding BGP-signaled Layer 2 VPNs? (Choose two.)

A. You must enable the Layer 2 VPN signaling NLRI.B. You must configure the virtual circuit identifier.C. You must specify the neighbor using the tunnel end-point IP address.D. You must define a unique site-identifier value.

Correct Answer: ADSection: MPLSExplanation


In the basic MPLS configuration of the PE devices using a circuit cross-connect (CCC), the PE devices are configured to use an interior gateway protocol (IGP),such as OSPF or IS-IS, as the routing protocol between the MPLS devices and LDP or RSVP as the signaling protocol.

When you are configuring a Layer 2 VPN, you must use BGP signaling. The BGP signaling automates the connections, so manual configuration of the associationbetween the LSP and the customer edge interface is not required.

A unique site-identifier value is part of this configuration


See the following for additional detailshttp://www.juniper.net/documentation/en_US/junos15.1/topics/example/mpls-ex-series-vpn-layer2.html

QUESTION 8Which two statements regarding VRF tables are correct? (Choose two.)

A. A PE router's VRF table stores routes received from directly connected CE devices.B. A PE router's VRF table stores routes received from its IGP from remote PE devices.C. A PE router's VRF table stores routes received from MP-BGP from remote PE devices.D. A PE router's VRF table stores routes received from all P and PE devices within the same AS.



When a PE device has a Layer 3 peering to a CE device it stores the routes received from the CE in a VRF to separate the routing information from other CEdevices.

PE to PE devices maintain a multi-protocol BGP (mpBGP / mBGP) peering

QUESTION 9You have been asked to implement routing policy on the PE devices in your AS and to ensure the correct customer routes are installed in the appropriate VRFtables. Which component should be used as a match condition within your policy?

A. BGP communitiesB. VLAN IDsC. route distinguisherD. circuit IDs

Correct Answer: ASection: MPLSExplanation


A BGP community is bit of “extra information” that you can add to one of more prefixes which is advertised to BGP neighbors. This extra information can be used


for things like traffic engineering or dynamic routing policies

QUESTION 10What is the purpose of a route target community in a Layer 3 VPN?

A. The community value is used to identify routes that should be imported by remote PEs.B. The community value is used to determine valid remote devices when signaling a Layer 3 VPN.C. The community value is used to identify the source of incoming routes.D. The community value is used to determine transit devices when signaling a Layer 3 VPN.



Route TargetsWhereas route distinguishers are used to maintain uniqueness among identical routes in different VRFs, route targets can be used to share routes among them.We can apply route targets to a VRF to control the import and export of routes among it and other VRFs.

A route target takes the form of an extended BGP community with a structure similar to that of a route distinguisher (which is probably why the two are so easilyconfused). One or more route targets can be affixed to routes within a VRF using the VRF configuration command route-target export:

ip vrf Customer_A rd 65000:100 route-target export 65000:100

http://packetlife.net/blog/2013/jun/10/route-distinguishers-and-route-targets/

A BGP community is a group of destinations that share a common property. Community information is included as a path attribute in BGP update messages. Thisinformation identifies community members and enables you to perform actions on a group without having to elaborate upon each member. You can use communityand extended communities attributes to trigger routing decisions, such as acceptance, rejection, preference, or redistribution.

The name of the community uniquely identifies it to the routing device and serves as the method by which routes are categorized.

http://www.juniper.net/techpubs/en_US/junos15.1/topics/concept/policy-bgp-communities-extended-communities-match-conditions-overview.html

QUESTION 11You have been asked to deploy a Layer 2 VPN for a new customer. What information will be present in the PE's associated VPN forwarding table? (Choose three.)


A. The customer site IDB. The route distinguisherC. The interface encapsulationD. The label baseE. The community name

Correct Answer: ACDSection: MPLSExplanation


The forwarding table contains the interface encapsulation, Customer Site ID, and label base

http://www.juniper.net/documentation/en_US/junos14.2/topics/reference/command-summary/show-route-forwarding-table-mpls-ex-series.htmlhttp://www.juniper.net/documentation/en_US/junos16.1/topics/concept/junos-software-routing-forwarding-table-overview.htmlhttp://www.juniper.net/documentation/en_US/junos15.1/topics/example/mpls-ex-series-vpn-layer2.html

QUESTION 12You have an established Layer 3 VPN where you are using static routing between your PE and CE devices. You must advertise their directly connected subnet toremote PE devices. Which two methods must you use? (Choose two.)

A. Use a site identifier.B. Use the VRF table label.C. Use a VRF export policy.D. Use a route distinguisher.



The vrf-table-label and VRF export policy are used

Site-ID's are used for L2VPNs not L3VPNshttp://www.juniper.net/documentation/en_US/junos12.3/topics/task/configuration/layer-three-vpns-introduction-to-configuration.htmlhttp://www.juniper.net/documentation/en_US/junos12.3/topics/usage-guidelines/vpns-configuring-the-local-site-on-pe-routers-in-layer-2-vpns.html


vrf-table-label maps the inner label of a packet to a specific VPN routing and forwarding (VRF) table. This allows the examination of the encapsulated IP header. Allroutes in the VRF configured with this option are advertised with the label allocated per VRF.http://www.juniper.net/documentation/en_US/junos12.3/topics/reference/configuration-statement/vrf-table-label-edit-routing-instances-vp.html

QUESTION 13You have been asked to verify the state of an LDP-signaled Layer 2 circuit. Which two commands would you use to verify the state of the connection? (Choosetwo.)

A. show mpls lspB. show l2circuit connectionsC. show l2circuit statisticsD. show ldp database



show mpls lsp - Display's information about configured and active dynamic Multiprotocol Label Switching (MPLS) label-switched paths (LSPs).show l2circuit connections - Display's the status information about Layer 2 virtual circuits from the local provider edge (PE) router to its neighbors.show ldp database - Display's entries in the LDP database.

http://www.juniper.net/documentation/en_US/junos12.3/topics/reference/command-summary/show-mpls-lsp.htmlhttps://www.juniper.net/documentation/en_US/junos15.1/topics/reference/command-summary/show-l2circuit-connections.htmlhttp://www.juniper.net/documentation/en_US/junos13.2/topics/reference/command-summary/show-ldp-database.html

QUESTION 14--Exhibit--



Referring to the exhibit, you have an established RSVP LSP between R1 and R5 when you experience a link failure between R2 and R4.

Which two statements are correct? (Choose two.)

A. R2 sends a ResvTear message upstream to R1 signaling the link failure.B. R2 sends a PathTear message upstream to R1 signaling the link failure.C. R4 sends a ResvTear message downstream to R5 signaling the link failure.D. R4 sends a PathTear message downstream to R5 signaling the link failure.

Correct Answer: ADSection: MPLSExplanation


ResvTear messages remove reservation states along a path. These messages travel upstream toward senders of the session. In a sense, ResvTear messagesare the reverse of Resv messages. ResvTear messages typically are initiated by a receiver application or by a router when its reservation state times out.

PathTear messages remove (tear down) path states as well as dependent reservation states in any routers along a path. PathTear messages follow the same pathas path messages. A PathTear typically is initiated by a sender application or by a router when its path state times out



Based on the illustration of the VPLS topology shown in the exhibit, which statement is true?

A. PE-C must have a spanning-tree protocol enabledB. CE-C must have BGP enabledC. Traffic forwarded from PE-C to PE-A is forwarded on to PE-BD. Traffic forwarded from PE-C to PE-A is not forwarded on to PE-B

Correct Answer: DSection: MPLSExplanation


Virtual Private LAN Service (VPLS) is a way to provide Ethernet-based multipoint to multipoint communication over IP or MPLS networks. It allows geographicallydispersed sites to share an Ethernet broadcast domain by connecting sites through pseudo-wires. The term 'sites' includes multiplicities of both servers and clients.The technologies that can be used as pseudo-wire can be Ethernet over MPLS, L2TPv3 or even GRE. There are two IETF standards track RFCs (RFC 4761 andRFC 4762) describing VPLS establishment.

In a VPLS, the local area network (LAN) at each site is extended to the edge of the provider network. The provider network then emulates a switch or bridge toconnect all of the customer LANs to create a single bridged LAN.

QUESTION 16You have configured MPLS and RSVP in your network using all of the Junos defaults. You have established an LSP in your network, which is reporting a status of"Up", but no traffic is using it. Which two statements reflect potential causes for this issue? (Choose two)

A. The LSP egress address is a physical interface addressB. family MPLS was omitted from the router configurationsC. No BGP routes are being advertised from the remote neighborD. The LSP egress address does not match the BGP next-hop address

Correct Answer: CDSection: MPLSExplanation


The LSP egress router might not be advertising any BGP routers, or the BGP routers and LSP egress address do not match


QUESTION 17Which operational mode command would you use to verify the presence of VPN routes on a PE device?

A. show route table bgp.l3vpn.0B. show route protocol bgp terse | countC. show route table inet.0D. show route route-type vpn



The bgp.l3vpn.0 table stores BGP routes learned from other PE routers. Routes in this table are copied into a Layer 3 VRF when there is a matching route table.

QUESTION 18Which statement is true of a Layer 2 circuit?

A. Layer 2 circuits use BGP for signalingB. Layer 2 circuits use OSPF for signalingC. Layer 2 circuits use LDP for signalingD. Layer 2 circuits rely on RSVP for signaling



A Layer 2 circuit is a point-to-point Layer 2 connection that uses LDP for signaling.

QUESTION 19You have been asked to provision a service provider's network to accommodate Layer 3 VPNs as defined in RPC 4364. Which three tasks must be performedbefore the provider core is ready to carry VPN traffic? (Choose three.)

A. All P routers and PE routers must be configured to support MPLS administrative-groups (colors)B. All PE routers must be configured to support Multiprotocol BGP (MP-BGP)


C. All P routers and PE routers must have a signaling protocol such as RSVP or LDP enabledD. All P routers and PE routers must have a discovery protocol such as LLDP or CDP enabledE. All P routers and PE routers must have MPLS reach ability to PE routers

Correct Answer: BCESection: MPLSExplanation


Administrative-Groups and Discovery protocols like LLDP & CDP are not a requirement, All other answers are a requirement as per the RFC

https://tools.ietf.org/html/rfc4364

QUESTION 20You would like two LDP routers on opposite sides of your network to become neighbors. Which LDP message is used to form this relationship?

A. basic discoveryB. extended discoveryC. peer discoveryD. remote discovery

Correct Answer: BSection: MPLSExplanation


Basic discovery is used to discover directly connected LDP peers. Extended discovery is used to discovery LDP peers that are not directly connected.

QUESTION 21Which label operation is performed by an MPLS ingress router?

A. PopB. PushC. ReplaceD. Swap




An "ingress router" is a Label Switch Router that is a starting point (source) for a given Label Switched Path (LSP) and is were the first label is applied to the IPPacket.

QUESTION 22An RSVP LSP in your network is operational but you are receiving complaints about network throughput across the LSP. You suspect that the RSVP bandwidthwas omitted from the router configuration.

Which operational mode command will help you verify your suspicions?

A. show interfaces terseB. show mpls lsp extensiveC. show rsvp neighbor detailD. show rsvp bandwidth



The command "show mpls lsp extensive" can be used to provide detailed information about an LSP

QUESTION 23You want to ensure that your RSVP LSPs are following a particular path across the network. Which RSVP object ensures that your desire will be met?

A. explicit route objectB. record route objectC. session objectD. traffic specification object

Correct Answer: A


Section: MPLSExplanation


Explicit route objects (EROs) are configured to ensure an LSP uses a specific path across the network.

QUESTION 24Which statement is true about the operation of Layer 2 VPNs?

A. Layer 2 VPNs require that CE devices use the same Layer 2 encapsulationB. Layer 2 VPNs do not permit CE devices to operate a Layer 3 protocol with each otherC. Service provider routers must evaluate the IP header of packets as they traverse their networkD. Layer 2 VPNs allow CEs to use different encapsulations on either side of the VPN



The PE and CE do not exchange routing information, and therefore Layer 2 information is used to transport the traffic. CEs can establish protocols such as OSPFover the L2VPN. L2VPNs can have an encapsulation mismatch on each side of the VPN.



Based on the illustration shown in the exhibit, what would PE-B do with a VPLS packet received from PE-A if the matching entry in its VPLS routing table showedthe destination was connected to PE-D?

A. PE-B would flood the packet to all attached PEsB. PE-B would forward the packet to the root PE deviceC. PE-B would forward the packet to all attached CE devicesD. PE-B would discard the packet



VPLS, in its implementation and configuration, has much in common with a Layer 2 VPN. In VPLS, a packet originating within a service provider customer’snetwork is sent first to a customer edge (CE) device (for example, a router or Ethernet switch). It is then sent to a provider edge (PE) router within the serviceprovider’s network. The packet traverses the service provider’s network over a MPLS label-switched path (LSP). It arrives at the egress PE router, which thenforwards the traffic to the CE device at the destination customer site.

The difference is that for VPLS, packets can traverse the service provider’s network in point-to-multipoint fashion, meaning that a packet originating from a CEdevice can be broadcast to all the PE routers participating in a VPLS routing instance. In contrast, a Layer 2 VPN forwards packets in point-to-point fashion only.

https://www.juniper.net/documentation/en_US/junos12.3/topics/concept/vpn-vpls-introduction.html


QUESTION 26You are logged into a PE router participating in a Layer 3 VPN as defined in RFC 4364. You would like to ping the remotely connected CE router's loopbackaddress. The address of the loopback is 122.161.2.1, the VPN routing-instance is called VPN-C. Which command will accomplish this goal?

A. ping instance VPN-C 122.161.2.1B. ping routing-instance VPN-C 122.161.2.1C. ping VPN-C 122.161.2.1D. ping vpn-instance VPN-C 122.161.2.1



To ping a destination from within a routing instance, you must source the ping from that routing instance.

QUESTION 27By default, which RSVP reservation style is used by the Junos OS?

A. fixed explicitB. fixed filterC. shared explicitD. wildcard filter



The fixed filter (FF) reservation style consists of distinct reservations among explicit senders. This reservation style is enabled on RSVP LSPs by default.

QUESTION 28You observe that VPN routes are hidden on your PE router Which situation accounts for these hidden routes?

A. The protocol next-hop is not found in inet.3


B. The protocol next-hop is not found in mpls.0C. The protocol next-hop is not found in bgp I3vpn.0D. The protocol next-hop is not found in inet.2



MPLS is used for forwarding, so there must be a next-hop in inet.3. This table stores the egress address of an MPLS label-switched path (LSP), the LSP name, andthe outgoing interface name. This routing table is used only when the local device is the ingress node to an LSP.

QUESTION 29By default, the Junos OS advertises which address(es) in LDP forwarding equivalency class (FEC) messages?

A. all router addressesB. all transit interfacesC. loopback addressD. primary transit interface address



By default Junos OS advertises loopback addresses into the LDP forwarding equivalency class (FEC)

QUESTION 30Which two statements are correct regarding VPLS mesh groups? (Choose two.)


A. Unicast packets destined to another PE router within the same mesh group are dropped by the local PE router.


B. Unicast packets destined to another PE router in a different mesh group are dropped by the local PE router.C. Broadcast, multicast, and unicast packets of unknown origin received from a PE router are flooded to all local CE routers.D. Broadcast, multicast, and unicast packets of unknown origin received from a PE router are flooded to all remote PE routers.



Unicast packets destined to another PE would be dropped, whereas Broadcast, Multicast, and unicast packets of an unknown origin are flooded to the local CE

QUESTION 31You are logged into a PE router participating in a Layer 3 VPN as defined in RFC 4364. You would like to ping the locally connected CE router's interface. Theaddress of the interface is 192.168.1.1; the VPN routing-instance is named VPN-A. Which command will accomplish this task?

A. ping routing-instance VPN-A 192.168.1.1B. ping instance VPN-A 192.168.1.1C. ping vpn-instance VPN-A 192.168.1.1D. ping VPN-A 192.168.1.1



Answer A shows the correct command. To ping a destination from within a routing instance, you must source the ping from the routing instance

QUESTION 32Before configuring an RSVP LSP in your network, you first apply a baseline configuration to all of the routers.

Which three configuration elements are minimally required in the baseline? (Choose three.)

A. family mpls on the loopback interfaceB. family mpls on the transit interfacesC. protocols ldp for the appropriate interfaces


D. protocols mpls for the appropriate interfacesE. protocols rsvp for the appropriate interfaces

Correct Answer: BDESection: MPLSExplanation


Protocol MPLS and RSVP must be configured for the appropriate interfaces, along with the MPLS protocol family on the transit interfaces.

QUESTION 33In your RSVP network you have configured three separate LSPs to the same egress address. You have made no other configuration changes to the forwardingdecisions made by the router. Which commands can you use to determine which LSP is being used to forward packets?

A. show route table inet.3B. show route table inet.4C. show rsvp neighborD. show rsvp session



The command "show route table inet.3" shows which LSP is being used for a given destination.

QUESTION 34Your customer would like to forward traffic using DLCI 600 and maintain Layer 2 information across a VPN. Which solution will meet these requirements?

A. a Layer 3 VPNB. a Layer 2 VPNC. Virtual Private LAN Service (VPLS)D. an IPsec VPN

Correct Answer: BSection: MPLS


Explanation


VPLS is an Ethernet-based point-to-multipoint L2VPN, whereas a Layer 2 VPN is a point-to-point L2VPN that also can work with frame-relay. The other options areLayer 3 VPNs.

QUESTION 35You have been asked to provision a service provider's network to accommodate Layer 3 VPNs as defined in RFC 4364. Which three tasks must be performedbefore the provider network is ready to carry VPN traffic? (Choose three.)

A. All Juniper Networks PE routers must be configured with an appropriate router-ID unique to the VPN.B. All Juniper Networks PE routers must be configured with an appropriate route-target unique to the VPN.C. All Juniper Networks PE routers must be configured with a routing-instance of type forwarding.D. All Juniper Networks PE routers must be configured with a routing-instance of type vrf.E. All Juniper Networks PE routers must be configured with a routing-instance containing the CE- facing interface.

Correct Answer: BDESection: MPLSExplanation


For a Layer 3 VPN configuration all PE routers must be configured with an appropriate route-target unique to the VPN, a routing-instance type of vrf (to maintain asperate routing table), and the routing-instance must contain the CE-facing interface.

QUESTION 36You have configured an RSVP LSP in your network and have assigned it one primary and two secondary paths.

Which command is used to validate that the LSP is using the primary path?

A. show rsvp interfaceB. show rsvp versionC. show rsvp neighbor detailD. show rsvp session detail

Correct Answer: DSection: MPLS


Explanation


show rsvp interface - shows what interfaces are configured under [edit protocols rsvp]show rsvp version - displays the RSVP version and timersshow rsvp neighbor detail - display the RSVP neighbor's in detailshow rsvp session detail - displays the current RSVP sessions in detail

http://www.juniper.net/documentation/en_US/junos15.1/topics/reference/command-summary/show-rsvp-session.html#jd0e1115

QUESTION 37Which LDP message is used to transmit labels and forwarding equivalency class (FEC) information?

A. advertisementB. discoveryC. notificationD. session



Advertisement messages create, change, and delete label mappings for forwarding equivalence classes (FECs). Discovery messages announce and maintain thepresence of a router in a network. Notification messages provide advisory information and signal error information. Session messages establish, maintain, andterminate sessions between LDP peers.

QUESTION 38By default, which Junos routing table stores RSVP egress router information?

A. inet.1B. inet.2C. inet.3D. inet.4

Correct Answer: C




The inet.3 routing table contains the host address of each LSP’s egress router. This routing table is used on ingress routers to route packets to the destinationegress router. BGP uses the inet.3 routing table on the ingress router to help in resolving next-hop addresses.


QUESTION 39An RSVP enabled router receives an RSVP reservation message for a new RSVP path. The router is unable to accommodate the reservation request.

Which action does the router take?

A. The router sends a ResvErr message to the upstream router.B. The router sends a ResvErr message to the downstream router.C. The router sends a ResvTear message to the upstream router.D. The router sends a ResvTear message to the downstream router.



RSVP uses unidirectional and simplex flows through the network to perform its function. The inbound router initiates an RSVP path message and sends itdownstream to the outbound router. The path message contains information about the resources needed for the connection. Each router along the path begins tomaintain information about a reservation.

When the path message reaches the outbound router, resource reservation begins. The outbound router sends a reservation message upstream to the inboundrouter. Each router along the path receives the reservation message and sends it upstream, following the path of the original path message. When the inboundrouter receives the reservation message, the unidirectional network path is established.

The resv message is sent from the receiver to the sender host along the reverse data path. At each node the IP destination address of the resv message willchange to the address of the next node on the reverse path and the IP source address to the address of the previous node address on the reverse path.

ResvTear messages remove reservation states along a path. These messages travel upstream toward senders of the session. In a sense, ResvTear messagesare the reverse of Resv messages. ResvTear messages typically are initiated by a receiver application or by a router when its reservation state times out.


ResvErr messages travel downstream towards the appropriate receivers, routed hop-by-hop using the reservation state. At each hop, the IP destination address isthe unicast address of a next-hop node.

http://www.freesoft.org/CIE/RFC/2205/26.htm

QUESTION 40What are two valid protocols used to signal VPLS in a network? (Choose two.)

A. RSVPB. CCCC. BGPD. LDP

Correct Answer: CDSection: MPLSExplanation


VPLS can use either BGP or LDP for signaling

QUESTION 41By default, which router in an MPLS LSP removes the MPLS header?

A. penultimate routerB. egress routerC. ingress routerD. ultimate router



The penultimate pop router is the second to the last router in the MPLS LSP and by default it pop's the last MPLS label


QUESTION 42Which table will a Junos-based MPLS ingress router first consult to determine the next hop for BGP routes reachable through an LSP?

A. inet.1B. mpls.0C. inet.3D. inet.0





Generally, BGP selects next-hop entries in the inet.3 routing table because their preferences are always lower than OSPF and IS-IS next-hop preferences. Whenyou configure LSPs, you can override the default preference for MPLS LSPs, which might alter the next-hop selection process.

When BGP selects a next-hop entry from the inet.3 routing table, it installs that LSP into the forwarding table in the Packet Forwarding Engine, which causespackets destined for that next hop to enter and travel along the LSP. If the LSP is removed or fails, the path is removed from the inet.3 routing table and from theforwarding table, and BGP reverts to using a next hop from the inet.0 routing table.


QUESTION 43You are asked to configure a new LSP in your network. The new LSP must take a specific path using a given set of routers.

What must you do to accomplish this task?

A. A named path must be defined and referenced as primary for the LSP.B. A named path must be defined and referenced as preferred for the LSP.C. A named path must be defined and given a low priority.


D. A named path must be defined and given a high priority.



To configure the path so that it follows a particular route, create a named path using the path statement, Then apply the named path by including the primary orsecondary statement.

The primary statement creates the primary path, which is the LSP’s preferred path. The secondary statement creates an alternative path. If the primary path can nolonger reach the egress router, the alternative path is used.

http://www.juniper.net/documentation/en_US/junos12.3/topics/usage-guidelines/mpls-configuring-primary-and-secondary-lsps.html

QUESTION 44You are asked to configure an MC-LAG, in active-active mode, between PE1 and PE2.

Which configuration is correct?

A. Option AB. Option BC. Option CD. Option D



Consider a sample topology in which a customer edge router, CE, is connected to two provider edge (PE) routers, PE1 and PE2, respectively. The two PE deviceseach have a link aggregation group (LAG) connected to the CE device. The configured mode is active -active, meaning that both PE routers’ LAG ports are activeand carrying traffic at the same time. PE1 and PE2 are connected to a single service provider router, P.

In this example, the CE router is not aware that its aggregated Ethernet links are connected to two separate PE devices. The two PE devices each have a LAGconnected to the CE device. The configured mode is active-active, meaning that both PE routers’ LAG ports are active and carrying traffic at the same time.


http://www.juniper.net/techpubs/en_US/junos13.3/topics/example/interfaces-active-active-bridging-mc-lag-scenario.html

QUESTION 45Your customer requests that you provide a transparent Layer 2 service between two of their remote locations. This service must allow them to pass tagged trafficfrom multiple VLANs. You decide to use Q-in-Q tunneling on the two provider edge MX Series routers that connect to the customer's CE devices.


A. The CE-facing interfaces on the PE devices must be configured as trunk ports.B. The CE-facing interfaces on the PE-devices must be configured as access ports.C. The PE-facing interfaces on the CE devices must be configured as trunk ports.D. The PE-facing interfaces on the CE devices must be configured as access ports.



The CE-facing interfaces on the PE-devices must be configured as access ports.http://www.juniper.net/documentation/en_US/junos15.1/topics/task/configuration/ccpe-mei-qinq-tunnel-pe-configure.html

QUESTION 46An established RSVP-signaled LSP suffers a link failure. What is one action taken by the local RSVP-enabled router?

A. A PathTear message is sent downstream.B. A PathErr message is sent upstream.C. A PathErr message is sent downstream.D. A PathTear message is sent upstream.



PathTear messages are sent downstream and remove (tear down) path states as well as dependent reservation states in any routers along a path. PathTearmessages follow the same path as path messages. A PathTear typically is initiated by a sender application or by a router when its path state times out.


PathTear messages are not required, but they enhance network performance because they release network resources quickly. If PathTear messages are lost ornot generated, path states eventually time out when they are not refreshed, and the resources associated with the path are released.

QUESTION 47Which two formats are valid route distinguisher formats? (Choose two.)

A. <MPLS label> : <VPN assigned number>B. <autonomous system number> : <VPN assigned number>C. <inbound interface index> : <VPN assigned number>D. <loopback IP address> : <VPN assigned number>



route-distinguisher (as-number:number | ip-address:number);

as-number:number—as-number is an assigned AS number and number is any 2-byte for 4-byte value. The AS number can be from 1 through 4,294,967,295. If theAS number is a 2-byte value, the administrative number is a 4-byte value. If the AS number is 4-byte value, the administrative number is a 2-byte value. A routedistinguisher consisting of a 4-byte AS number and a 2-byte administrative number is defined as a type 2 route distinguisher in RFC 4364 BGP/MPLS IP VirtualPrivate Networks.

ip-address:number—ip-address is an IP address in your assigned prefix range (a 4-byte value) and number is any 2-byte value.

https://www.juniper.net/techpubs/en_US/junos12.1/topics/reference/configuration-statement/route-distinguisher-edit-routing-instances.html

QUESTION 48You are using RSVP in your network to signal MPLS LSPs. You are asked to ensure that the egress MPLS router receives the full label stack, containing both thehop-by-hop and VPN label.

A. Use the set protocols mpls explicit-null command.B. Use the set protocols mpls expand-loose-hop command.C. Use the set protocols rsvp keep-multiplier command.D. Apply set protocols rsvp interface <:interface> no-aggregate to the egress interface.

Correct Answer: A




explicit-null advertises label 0 to the egress router of an LSP. Label 0 is the explicit NULL label, whereas label 3 is the implicit NULL label,

The implicit NULL label is the label that has a value of 3. An egress LSR assigns the implicit NULL label to a FEC if it does not want to assign a label to that FEC,thus requesting the upstream LSR to perform a pop operation.

The use of implicit NULL at the end of an LSP is what causes the penultimate hop popping (PHP) router to POP the last label within the MPLS label static.

QUESTION 49What is the role of the route distinguisher (RD) in a Layer 3 VPN?

A. The RD controls the allocation of MPLS labels within a VRF.B. The RD allows different VRFs to contain the same IP prefixes.C. The RD is used to create unique routing processes within the global routing instance.D. The RD is used to control the import and export of routes within a VRF.



A route distinguisher is an address qualifier used only within a single internet service provider's Multiprotocol Label Switching (MPLS) network. It is used todistinguish the distinct virtual private network (VPN) routes of separate customers who connect to the provider.

The route distinguisher has only one purpose: to make IPv4 prefixes globally unique. It is not used for IP forwarding by the provider's core (non-edge) routers(within the MPLS cloud), but it is used by the edge routers to identify which VPN a packet belongs to.

QUESTION 50In a Junos device functioning as an MPLS transit router, which routing table is used when performing a forwarding lookup for an incoming packet?

A. mpls.3B. inet.0C. inet.3


D. mpls.0





MPLS also maintains an MPLS path routing table (mpls.0), which contains a list of the next label-switched router in each LSP. This routing table is used on transitrouters to route packets to the next router along an LSP.

When a transit or egress router receives an MPLS packet, information in the MPLS forwarding table is used to determine the next transit router in the LSP or todetermine that this router is the egress router.


QUESTION 51Your customer requests that you provide a transparent Layer 2 service between two of their remote locations. This service must allow the customer to pass taggedtraffic from multiple VLANs. You decide to use Q-in-Q tunneling on the two provider edge MX Series routers that connect to the customer's CE devices.


A. As traffic leaves the Q-in-Q tunnel, the S-VLAN tag will be removed from the frames.B. As traffic enters the Q-in-Q tunnel, an S-VLAN tag will be added to the frames.C. As traffic enters the Q-in-Q tunnel, a C-VLAN tag will be added to the frames.D. As traffic leaves the Q-in-Q tunnel, the C-VLAN tag will be removed from the frames.

Correct Answer: ABSection: MPLSExplanation



Explanation:

Q-in-Q tunneling allows service providers on Ethernet access networks to extend a Layer 2 Ethernet connection between two customer sites. Using Q-in-Qtunneling, providers can also segregate or bundle customer traffic into fewer VLANs or different VLANs by adding another layer of 802.1Q tags. Q-in-Q tunneling isuseful when customers have overlapping VLAN IDs, because the customer’s 802.1Q (dot1Q) VLAN tags are prepended by the service VLAN (S-VLAN) tag. TheJuniper Networks Junos operating system (Junos OS) implementation of Q-in-Q tunneling supports the IEEE 802.1ad standard.

https://www.juniper.net/documentation/en_US/junos12.3/topics/concept/qinq-tunneling-ex-series.html

QUESTION 52You are asked to establish an MPLS LSP between two sites. You are required to ensure the LSP traverses specific routers within your network. Which solution iscorrect?

A. Enable traffic engineering within LDP and define the explicit route the LSP must follow.B. Implement RSVP and define the explicit route the LSP must follow.C. Enable traffic engineering within RSVP and define the explicit route the LSP must follow.D. Implement LDP and define the explicit route the LSP must follow.



On the ingress router, create an explicit-path LSP, and specify the transit routers between the ingress and egress routers. In this configuration, no constrained-pathcomputation is performed. For the primary path, all intermediate hops are strictly specified so that its route cannot change. The secondary path must travel throughrouter 14.1.1.1 first, then take whatever route is available to reach the destination. The remaining route taken by the secondary path is typically the shortest pathcomputed by the IGP.

http://www.juniper.net/documentation/en_US/junos15.1/topics/example/mpls-lsp-explicit-path-configuring.html

QUESTION 53You are designing a new MPLS network that contains 1000 nodes. To provide for any-to-any connectivity for your customer base, you have decided to build a fullmesh of RSVP LSPs. You are concerned with scalability of the overall network and with the resources used by the devices. Which RSVP feature is used toaccomplish your design goals.

A. authenticationB. fast rerouteC. hello interval


D. refresh reduction



The RSVP refresh reduction, based on RFC 2961, addresses the problem of scalability and reliability that result from relying on periodic refresh messages.

QUESTION 54Your RSVP network is being designed to support end-to-end class of service (CoS) using best practices.

Which MPLS label should be advertised by the egress router in this situation?

A. 0B. 1C. 2D. 3



MPLS label 0, or explicit null, should be used so that the label is popped at the egress router.

QUESTION 55Which statement is true about the operation of a Layer 3 VPN as defined in RFC 4364?

A. BGP is used for forwarding and MPLS is used for routingB. LDP is used for routing and RSVP is used for forwardingC. BGP is used for routing and MPLS is used for forwardingD. LDP is used for forwarding and MPLS is used for routing

Correct Answer: CSection: MPLS


Explanation


BGP is used for routing and MPLS is used for forwarding. LDP and RSVP can be used as the signaling protocol.

QUESTION 56Which two RSVP messages are used to establish a new LSP? (Choose two.)

A. pathB. pathconfirmC. ResvD. ResvConfirm



RSVP path messages are sent downstream from the ingress router to the egress router. RSVP Resv messages are then sent upstream from the egress router tothe ingress router. The path messages contain information about resources needed, and the Resv messages reserve these resources.

QUESTION 57By default, the Junos OS advertises which address(es) in LDP forwarding equivalency class (FEC) messages?

A. all device addressesB. all transit interfacesC. the loopback addressD. the primary transit interface address




By default, the loopback address is advertised in the FEC.

QUESTION 58Which label operation is performed by an MPLS transit router?

A. popB. pushC. replaceD. swap



The swap operation removes an existing MPLS label from an IP packet and replaces it with an new MPLS label.

QUESTION 59Where does the Junos OS place an MPLS header in a data packet?

A. before the Layer 2 headerB. encoded within the Layer 2 headerC. before the Layer 3 headerD. after the Layer 3 header



The MPLS header is placed before the Layer 3 header.

QUESTION 60You have configured refresh reduction in your RSVP network but you suspect that some of the Junos devices are not correctly operating in that mode. Whichoperational mode command can be used to view the refresh messages sent and received?



A. show rsvp interfaceB. show rsvp versionC. show rsvp neighbor detailD. show rsvp session detail



The command "show rsvp neighbor detail" provides information about refresh reduction.

QUESTION 61Which two statements are correct about provider-provisioned Layer 3 VPNs? (Choose two.)

A. PE routers maintain forwarding tables for each customer VPNB. PE routers offer a Layer 2 circuit to each CE deviceC. PE routers and CE routers participate in conventional IP routingD. PE routers exchange VPN traffic through their internal routing protocols



Each routing instance you created on the PE will create a separate table. PE routers and CE routers participate in conventional IP routing, each using a dynamic orstatic routing protocol

QUESTION 62Your customer needs to communicate between four remote sites using Ethernet and would like to maintain IP reachability between devices using a single /24


network. The customer will need to use ARP from one site to another.

Which solution will meet these requirements?

A. a Layer 2 VPNB. a Layer 2 circuitC. a virtual private LAN service (VPLS)D. a Layer 3 VPN as defined in RFC 4364



VPLS is an Ethernet-based point-to-multipoint L2VPN, whereas a Layer 2 VPN or Layer 2 circuit is a point-to-point L2VPN.

QUESTION 63Which statement is true about the operation of a Layer 2 VPN?

A. The service provider will use a routing protocol from the PE to CEB. A Layer 2 VPN transports packets based on Data Link Layer headersC. Layer 2 VPNs cannot transport Layer 3 protocol informationD. VPN signaling will be performed by RSVP



The PE and CE do not exchange routing information, and therefore Layer 2 information is used to transport the traffic. CEs can establish protocols such as OSPFover the L2VPN.

QUESTION 64Customers complain that they cannot reach remote sites. You notice that your VPN routes are hidden on PE routers and you suspect that a labe-switched path(LSP) is down.


Which command will confirm MPLS reachability to a remote PE?

A. show route table mpls.0B. show route table inet.3C. show route protocol bgp terseD. show route protocol mpls



MPLS is used for forwarding, so there must be a next hop in inet.3. This table stores the egress address of an MPLS label-switched path (LSP), the LSP name, andthe outgoing interface name. This routing table is sued only when the local device is the ingress node to an LSP.

QUESTION 65An RSVP LSP in your network is not operational and you suspect that the "family mpls" statement was omitted from the device configuration.

Which operational mode command will help you to verify your suspicions?

A. show interface terseB. show mpls lspC. show rsvp sessionD. show rsvp interface



The "show interfaces terse" command will show you which families are configured.

QUESTION 66Which statement is true about the operation of a Layer 3 VPN as defined in RFC 4364?

A. The majority of the configuration is performed on the service provider's PE routers


B. The majority of the configuration is performed on the service provider's P routersC. The majority of the configuration is performed on the customer's CE routersD. The majority of the configuration is performed on the customer's PE routers



The routing-instance configuration for the L3VPN is performed on the PE's which is the majority of the configuration

QUESTION 67In your network, you have two LDP routers connected across four physical interfaces. You also have enabled LDP to separate on all four of those interfaces.

What is the resulting outcome of your configuration between those two devices?

A. One session is built across one neighbor relationshipB. One session is built across four neighbor relationshipsC. Four sessions are built across one neighbor relationshipD. Four sessions are built across four neighbor relationships



One LDP session is established across the four interfaces

QUESTION 68You are troubleshooting the status of an RSVP LSP and the output of the "show mpls interface" command is blank.

Which statements describes the reason for the blank output?

A. Authentication was not configured on the local interfaceB. "family mpls" was not configured on the logical interfaceC. No configuration was added to the [edit protocols mpls] hierarchy


D. No configuration was added to the [edit protocol rsvp] hierarchy



You must add the mpls configuration within the [edit protocols mpls] hierarchy.

Example

configureset protocols mpls interface ge-1/1/0.0commit and-quit

QUESTION 69Your global MPLS network is using LDP end-to-end across 5000 nodes. Within the core of the network, you are tunneling LDP across an RSVP core.

When an MPLS packet reaches the ingress RSVP router, which label operation is performed?

A. pushB. double pushC. pop and pushD. swap and push


Explanation/Reference:Explanation

When an MPLS packet reaches the ingress RSVP router, it swaps the LDP label that is on top of the stack and pushes an RSVP label onto the top of the stack sothat the packet can now be switched by the RSVP LSP.

QUESTION 70Your network is using the Junos default MPLS settings.

Which label operation is performed by penultimate router?



A. popB. pushC. replaceD. swap



The pop operation removes a label from the beginning of the packet. Once the label is removed, the TTL is copied from the label into the IP packet header, and theunderlying IP packet is forwarded as a native IP packet.


Protocol Independant Routing


[edit policy-options]user@router# show

policy-statement load-balance { from { route-filter 10.243.0.0/24 exact; route-filter 10.224.1.0/24 exact; } then { load-balance per-packet; }}


You have been asked to configure per-packet load balancing. Referring to the exhibit, which configuration correctly applies the load-balancing policy?

A. [edit routing-options]user@router# showforwarding-options {export load-balance;}

B. [edit routing-options]user@router# showstatic {export load-balance;}

C. [edit routing-options]user@router# showforwarding-table {export load-balance;}

D. [edit routing-options]user@router# showrouting-table {export load-balance;


}

Correct Answer: CSection: Protocol Independant RoutingExplanation


QUESTION 2[edit]user@router# show routing-options

rib-groups { test { import-rib [ walter.inet.0 nancy.inet.0 ]; }}


Referring to the exhibit, what is the result of the RIB group configuration?


A. All routes from the walter.inet.0 and the nancy.inet.0 routing tables will be imported into the default master routing instance.B. Routes from the walter.inet.0 routing table will be imported into the nancy.inet.0 routing table.C. All routes will be shared between the walter.inet.0 and the nancy.inet.0 routing tables.D. Routes from the nancy.inet.0 routing table will be imported into the walter.inet.0 routing table.

Correct Answer: BSection: Protocol Independant RoutingExplanation


A RIB group is a way to have a routing protocol, in most cases, place information in multiple route tables. Within the Junos software configuration language, RIB


groups must first be defined, before being applied.

The format of the import-rib statement in a RIB group is:

routing-option { rib-group { <rib-group name> { import-rib [ source-routing table destination routing table1 destination routing table2 ......... ]

https://kb.juniper.net/InfoCenter/index?page=content&id=kb16133&actp=search

QUESTION 3You are logged into a router and have navigated to the [edit routing-options] level of the hierarchy. You have been asked to create a static route that will use10.10.10.1 as its primary next-hop and 10.10.10.5 as its secondary next-hop.

Which command correctly configures this scenario?

A. set static route 8/8 10.10.10.1 qualified-next-hop 10.10.10.5 pref 10B. set static route 8/8 next-hop 10.10.10.1 secondary-next-hop 10.10.10.5 preference 10C. set static route 8/8 next-hop 10.10.10.1 qualified-next-hop 10.10.10.5 preference 10D. set static route 8/8 next-hop [10.10.10.1 10.10.10.5] pref 10



"set static route 8/8 next-hop 10.10.10.1 qualified-next-hop 10.10.10.5 preference 10", uses the correct syntax to configure a static route that will use 10.10.10.1,with a default route preference of 5, as its primary next hop, and 10.10.10.5 as an alternate next hop, with a configured route preference value of 10. The next hopwith the lowest route preference will then be selected as the primary route. In this scenario it would be 10.10.10.1 with a default route preference of 5.

QUESTION 4Which Junos operational mode command is used to verify that load balancing is working as expected?

A. show route allB. show route extensiveC. show route balancingD. show route forwarding-table


Correct Answer: DSection: Protocol Independant RoutingExplanation


The command "show route forwarding-table" is used to verify that load balancing is working. Under the "Type" column in the output look for the value "ulst", whichindicates a list of unicast next hops.


Which command correctly configures this setup?

A. set static route 0/0 76.13.10.2 qualified-next-hop 43.18.7.1 pref 10B. set static route 0/0 next-hop 43.18.7.1 secondary-next-hop 76.13.10.2 preference 10C. set static route 0/0 next-hop [76.13.10.2 10.10.10.5] pref 10D. set static route 0/0 next-hop 43.18.7.1 qualified-next-hop 76.13.10.2 preference 10



Answer "set static route 0/0 next-hop 43.18.7.1 qualified-next-hop 76.13.10.2 preference 10" uses the correct syntax to configure a static route that will use43.18.7.1, with a default route preference of 5, as its primary next hop, and 76.13.10.2 as an alternate next hop, with a configured route preference value of 10. Thenext hop with the lowest route preference will then be selected as the primary route. In this scenario, it would be 43.18.7.1 with a default route preference of 5.

QUESTION 6You have been asked to define a default gateway for traffic leaving a router. This route should use interface so-0/0/0 as its next-hop. Which type of route would besuited for this scenario?

A. a static routeB. a generated routeC. a martian route


D. an aggregate route

Correct Answer: ASection: Protocol Independant RoutingExplanation


You should use a static route for this scenario. Generated and aggregate routes are single routes that represent a group of more specific routes. The Junos OS candefine address ranges that should not be globally routed in the Internet. These routes are called martian routes.


policy-options { policy-statement load-balance { from { route-filter 10.0.0.0/8 orlonger; route-filter 172.16.0.0/12 orlonger; route-filter 192.168.0.0/16 orlonger; then { load-balance per-packet; } }}

Click the Exhibit button

When the Junos configuration shown in the exhibit is applied to the router, which routes in the forwarding table will begin load-balancing packet flows?

A. all routes in the forwarding tableB. all OSPF routes in the forwarding tableC. all BGP routes in the forwarding tableD. all RFC 1918 routes in the forwarding table




Explanation:

All of the routes in the "from" statement of the policy are RFC 1918 routes. So in this scenario, the device would load-balance all RFC 1918 routes in the forwardingtable.

QUESTION 8Under which Junos configuration hierarchy is a load-balancing policy applied?

A. [edit routing-options family inet]B. [edit forwarding-options family inet]C. [edit routing-options forwarding-table]D. [edit forwarding-options forwarding-table]



On a Junos device, a load-balancing policy is applied under the [edit routing-options forwarding-table] hierarchy. Keep in mind that a load-balancing policy affectsonly the local device's forwarding behavior. To have all devices in the network load balance, you must create and apply a similar policy on each device.

QUESTION 9How many equal-cost paths can be assigned to a single route in the Junos OS?

A. 4B. 16C. 32D. 64



On Juniper Networks security devices, the maximum number of next-hop addresses in an ECMP set that can be installed in the forwarding table is 16. If there aremore than 16 next-hop addresses in an ECMP set, only the first 16 addresses are used.


http://www.juniper.net/techpubs/en_US/junos15.1/topics/concept/routing-policy-security-ecmp-flow-based-forwarding-understanding.html

QUESTION 10In your network, you have two LDP routers connected across four physical interfaces. You have also enabled LDP to operate on all four of those interfaces. What isthe resulting outcome of your configuration between those two routers?

A. One session is built across one neighbor relationshipB. One session is built across four neighbor relationshipsC. Four sessions are built across one neighbor relationshipD. Four sessions are built across four neighbor relationships



QUESTION 11By default, which three criteria are used by the Junos load-balancing algorithm to determine a traffic flow? (Choose three.)

A. protocolB. source portC. destination portD. source addressE. destination address

Correct Answer: ADESection: Protocol Independant RoutingExplanation


The tree criteria used by the Junos load-balancing algorithm to determine flow are protocol, source address, and destination address. The fourth parameter is theincoming interface index. The Junos OS also allows you to add Layer 3 and Layer 4 port data to determine flow. By default, IPv6 packets are automatically load-balanced based on Layer 3 and Layer 4 information and traffic class.

QUESTION 12


Which two statements reflect benefits of performing per-flow load balancing over per-packet load balancing? (Choose two.)

A. All physical links in the network are used equally.B. Packets arrive at the destination in the order they were sent.C. Provides easier implementation of class of service policies.D. Allows the destination host to re-order packets and increase performance.

Correct Answer: BCSection: Protocol Independant RoutingExplanation


Unlike per-packet load balancing, per-flow load balancing maintains individual flow between end stations. This results in a number of benefits, such as the packetsgenerally arriving at the destination in the order in which they were sent, thereby eliminating the need for the receiving device to reorder packets. In addition,because similar traffic uses the same path through the network, network-wide policies such as class of service (CoS) are easier to implement.

QUESTION 13You have been asked to identify what the contributing routes are for route 204.7.15/21. Which command will show this information?

A. show route 204.7.15/21B. show route 204.7.15/21 extendedC. show route 204.7.15/21 exact summaryD. show route 204.7.15/21 detail



The command "show route 2014.7.15/21 detail" will identify the contributing routes for prefix 204.7.15/21. The command "show route 204.7.15/21" defaults to thebrief level of information and will not show you contributing routes. Answers B and C are incorrect because of syntax and invalid options.

QUESTION 14When displaying the forwarding table, which designation indicates that load balancing is working correctly?

A. ucst


B. msctC. ulstD. mlst



You can use the command "show route forwarding-table" to check load balancing. The "ulst" forwarding table designation is used to indicate that load balancing isworking correctly. The "ulst" value indicates a list of unicast next hops. A packet sent to this next hop goes to any next hop in the list.


From the output shown in the exhibit, what would happen to a packet destined for address 172.29.3.5?

A. The address is not in the aggregate range; the packet is sent to the Routing Engine.B. The address is in the aggregate range; the packet will be silently dropped.C. The address is not in the aggregate range; the packet will be forwarded.


D. The address is in the aggregate range; the packet will be dropped.



Although the destination address associated with 172.29.3.5 matches the aggregate route, it does not match any of the contributing routes for the aggregate route.Because 172.29.3.5 does not match any of the contributing routes, the software drops the packet and generates and sends ICMP network unreachable messagesback to the source device. The described behavior assumes the default next-hop type of reject.


Which command correctly configures this setup?

A. set static route 0/0 76.13.10.2 qualified-next-hop 43.18.7.1 pref 10B. set static route 0/0 next-hop 43.18.7.1 secondary-next-hop 76.13.10.2 preference 10C. set static route 0/0 next-hop [76.13.10.2 10.10.10.5] pref 10D. set static route 0/0 next-hop 43.18.7.1 qualified-next-hop 76.13.10.2 preference 10



QUESTION 17You are logged into a router and have navigated to the [edit routing-options] level of the hierarchy. You have been asked to define an aggregate route for172.30/16. Which command correctly configures this setup?

A. set summary route 172.30/16B. set aggregate route 172.30/16C. set route aggregate 172.30/16D. set route summary 172.30/16




QUESTION 18


You work for the regional Internet service provider shown in the exhibit. You have a partial BGP table and are receiving a 10.100/16 route from your upstream ISP.You have been asked to configure a default route that can be sent to your downstream customer. This route should forward customer traffic toward your upstreamTier 1 ISP as long as the 10.100/16 route is present.

What would accomplish this goal?

A. Create and announce an aggregate default route.B. Create and announce a static default route with a next-hop of discard.C. Create and announce a static default route with a next-hop of reject.D. Create and announce a generated default route.



Based on this scenario, you should create a generated default route. The generated default route receives the next hop of the primary contributing route of10.100/16 from teh ISP as long as the route is present.


QUESTION 19You have three aggregate routes all with the same route preference. What is the second parameter used to determine the active route?

A. lowest metric valueB. secondary route preferenceC. highest metric valueD. lowest community value



The Junos OS provides support for alternate and tiebreaker preferences, and some of the routing protocols, including BGP and label switching, use theseadditional preferences. With these protocols, you can specify a primary route preference (by including the preference statement in the configuration), and asecondary preference that is used as a tiebreaker (by including the preference2 statement). You can also mark route preferences with additional route tiebreakerinformation by specifying a color and a tiebreaker color (by including the color and the tiebreaker color2 statements in the configuration).color and color2 statementsare even finer-grained preference values that Junos OS uses when preference and preference2 statements fail to break the tie during route selection.

http://www.juniper.net/documentation/en_US/junos14.2/topics/concept/routing-protocols-route-preferences-overview.html

QUESTION 20Which two statements are correct about a generated route? (Choose two.)

A. A generated route requires at least two contributing active routes to be active.B. A generated route has a route preference of 150.C. The primary contributing route is the route with the lowest preference that falls within the aggregate range of prefixes.D. A generated route receives the next hop for the primary contributing route.

Correct Answer: CDSection: Protocol Independant RoutingExplanation


QUESTION 21Exhibit


10.10.14.0/2410.10.15.0/2410.10.16.0/2410.10.17.0/24

Which aggregate route would represent all four routes shown in the exhibit?

A. 10.10.0.0/19B. 10.10.0.0/21C. 10.10.0.0/20D. 10.10.0.0/22




[edit routing-options]user@host# showrib-groups { test { import-rib [inet.0 user-a.inet.0]; }} Referring to the exhibit, which two statements are correct? (Choose two.)

A. The routes in inet.0 are imported into user-a.inet.0B. The RIB group can be applied to OSPF.C. The RIB group cannot be applied to OSPF.D. The routes in user-a.inet.0 are imported into inet.0

Correct Answer: ABSection: Protocol Independant Routing


Explanation



[edit]user@host# show routing-optionsstatic { route 172.29.0.0/24 { next-hop 172.15.27.1; no-readvertise; } route 172.28.0.0/24 next-hop 172.15.27.1; route 172.29.0.0/16 next-hop 172.15.27.1; route 172.29.0.0/17 next-hop 172.15.27.1; route 172.29.0.0/8 next-hop 172.15.27.1; }}

[edit]user@host# show policy-optionspolicy-statement export-static-to-ospf { term match-key-static-routes { from { protocol static; route-filter 172.29.0.0/16 longer; } then accept; }} Referring to the exhibit, which static route will be exported into OSPF?

A. 172.29.0.0/16B. 172.29.0.0/17C. 172.28.0.0/24D. 172.29.0.0/24




QUESTION 24A Junos device has a route in the inet.0 routing table with four valid physical next hops assigned to it.

By default, how many next hops are entered into the forwarding table?

A. 1B. 4C. 8D. 16



By default, the Junos OS randomly selects one next hop to enter into the forwarding table. You can alter this behavior by using a policy.

QUESTION 25You have been asked to identify the contributing prefixes for aggregate route 181.77.5/24. Which command will display this information?

A. show route 181.77.5/24 detailB. show route 181.77.5/24C. show route 181.77.5/24 exact summaryD. show route 181.77.5/24 extended




The command "show route 181.77.5/24 detail" will display the contributing routes for route 181.77.5/24


policy-options { policy-statement load-balance { then { load-balance per-packet; } }}

When the configuration shown in the exhibit is applied, which routes in the forwarding table will begin load-balancing packet flows?

A. all routes in the forwarding tableB. all OSPF routes in the forwarding tableC. all BGP routes in the forwarding tableD. all RFC 1918 routes in the forwarding table



Because the policy in the exhibit has no from statement, all routes in the forwarding table match the policy. Note that the "load-balancing per-packet" statementactually means load balance per flow on modern Junos devices.

QUESTION 27Your Junos device has a route in the inet.0 routing table with four valid physical next hops assigned to it.

Which to events prompt an update to the information in the forwarding table for this route? (Choose two.)

A. A fifth physical next hop is added to the routeB. A configuration change is committed on the deviceC. A packet is forwarded towards the route destinationD. One of the four physical next hops is removed from the route


Correct Answer: ADSection: Protocol Independant RoutingExplanation


Forwarding table information will be updated for this route when a fifth physical next hop is added to the route, or when one of the four physical next hops isremoved from the route.

QUESTION 28By default, which load-balancing algorithm does the Junos OS use for BGP routes?

A. per-flowB. per-prefixC. per-packetD. per-neighbor



By default, the Junos OS uses per-prefix load balancing for BGP routes.

QUESTION 29From the [edit routing-options] hierarchy, which command correctly configures an aggregate route for 64.18.128/17

A. set aggregate route 64.18.128/17B. set summary route 64.18.128/17C. set route aggregate 64.18.128/17D. set route summary 64.18.128/17




The set aggregate route 64.18.128/17 command correctly defines an aggregate route for 64.18.128/17. The default next hop for aggregate routes is reject, whichsends an ICMP unreachable message when incoming traffic does not match one of the contributing routes.

QUESTION 30Exhibit

[edit]user@router# show routing-optionsstatic { router 0.0.0.0/0 { next hop 10.10.10.1; qualified-next hop 10.10.10.2 { preference 6; } }}aggregate { route 0.0.0.0/0;}generate { route 0.0.0.0/0;}

Based on the exhibit, how will traffic using the 0.0.0.0 route exit the device?


A. It will use the next hop 10.10.10.2 when availableB. It will use the next hop 10.10.10.1 when availableC. It will use the next hop of the generated routeD. It will use the next hop of the aggregate route




Based on the exhibit, all traffic using the 0.0.0.0 route will exit the device using the route with the lowest route preference. In this case it is the static route 0.0.0.0with a next hop of 10.10.10.1, which has the default route preference of 5.


OSPF

QUESTION 1Which OSPF LSA type is sent from the ABR to describe an ASBR that is in an area to which it is connected?

A. Type 7B. Type 5C. Type 4

http://www.gratisexam.com/D. Type 3

Correct Answer: CSection: OSPFExplanation


QUESTION 2What are two functions of an OSPF BDR? (Choose two.)

A. The BDR advertises link-state information with all other OSPF routers on the segment.B. The BDR forms an adjacency with all other OSPF routers on the segment.C. The BDR is ready to assume the role of the DR device if it fails.D. The BDR functions can be distributed to the DR device on the segment.

Correct Answer: BCSection: OSPFExplanation


QUESTION 3Which OSPF adjacency state is reached when a hello packet has been sent, but bidirectional communication has not been established?


A. DownB. InitC. 2-wayD. ExStart

Correct Answer: BSection: OSPFExplanation


QUESTION 4What is a reason for an OSPF router to display a designated router ID of 0.0.0.0?

A. The MTU is mismatched.B. The subnet mask is mismatched.C. The interface type is point-to-point.D. The interface type is broadcast.



QUESTION 5Which two OSPF areas allow external routes? (Choose two.)

A. backbone areaB. not-so-stubby areaC. stub areaD. totally stubby area

Correct Answer: ABSection: OSPFExplanation



QUESTION 6Which LSA packet types are originated only by an OSPF ABR router?

A. Type 2 and Type 3B. Type 3 and Type 4C. Type 5 and Type 6D. Type 6 and Type 7



QUESTION 7In an OSPF environment, which two configuration parameters are used to determine which router is the DR? (Choose two.)

A. The router with the highest priorityB. The router with the lowest priorityC. The router with the highest RIDD. The router with the lowest RID

Correct Answer: ACSection: OSPFExplanation


QUESTION 8You have entered the show ospf route command and see routes with a metric type of EXT2.

What does this indicate?

A. These routes are OSPF interarea routes.B. These routes have been redistributed into OSPF and are using a Type 2 metric.


C. These routes are preferred over the same routes with an EXT1 metric.D. These routes are OSPF intra-area routes.



QUESTION 9You want to verify the frequency and type of SPF calculations on your JunOS device.

Which command displays this information?

A. show ospf database | match logB. show spf logC. show ospf logD. show ospf statistics



QUESTION 10You are troubleshooting an OSPF adjacency that is stuck in the ExStart state.

What would be the correct step to resolve the problem?

A. Look for a mismatched IP subnet or mask.B. Determine whether the neighbor is a DR-Other.C. Determine whether the hello and dead intervals are the same on both sides.D. Review the MTU settings to ensure that they match.

Correct Answer: DSection: OSPFExplanation



QUESTION 11You are asked to redistribute routes into OSPF.

Which action accomplishes this task?

A. Create a redistribution policy and apply it as an export policy under the [edit protocols ospf area] hierarchy.B. Create a redistribution policy and apply it as an import policy in the [edit protocols ospf] hierarchy.C. Create a redistribution policy and apply it as an import or an export policy in the [edit protocols ospf] hierarchy.D. Create a redistribution policy and apply it as an export policy in the [edit protocols ospf] hierarchy.



QUESTION 12You are configuring OSPF on a Junos device; however, you have not configured a router ID.

What is the default behavior in this situation?

A. If the loopback is configured with a 127/8 address, it will be used.B. If the loopback is not configured, it will use the interface with the highest IP address.C. If the loopback is configured and does not have a usable address, the IP address associated with the first hardware interface is used.D. If you configure a dedicated management address and include that interface in OSPF, it will be used as the router ID.



QUESTION 13-- Exhibit --


user@router> show route 0/0 exact detail

inet.0: 14 destinations, 14 routes (14 active, 0 holddown, 0 hidden)0.0.0.0/0 (1 entry, 1 announced)*Aggregate Preference. 130Next hop type. Router, Next hop index:Next-hop reference count: 4Next hop: 172.30.25.1 via ge-0/0/1.100, selectedState.Local AS: 65400Age. 1:03:46Task: AggregateAnnouncement bits (2): 0-KRT 2-OSPFAS path: IFlags: Generate Depth: 0 ActiveContributing Routes (1):10.0.0.0/16 proto BGP


You are advertising the route in the exhibit to your OSPF neighbors.

What happens if the 10.0.0.0/16 route is unavailable?

A. The default route will remain active and will "blackhole" all traffic from your OSPF peers.B. The default route will become unavailable and will no longer be advertised to your OSPF peers.C. The default route will remain active and will continue to be advertised to your OSPF peers.D. The default route will become unavailable and will continue to be advertised to your OSPF peers.




interfaces {


ge-1/0/3 { unit 0 { family inet { address 192.168.1.1/30; } } } ge-1/1/0 { unit 0 { family inet { address 10.100.10.1/30; } } } fxp0 { unit 0 { family inet { address 10.2.1.13/28; } } } lo0 { unit 0 { family inet { address 10.100.1.1/32; address 127.0.0.1/32; } } }}protocols { ospf { area 0.0.0.0 { interface ge-1/0/3.0; interface ge-1/1/0.0; } }}

The router was just powered on.

Referring to the exhibit, what is the OSPF RID?


A. 192.168.1.1B. 10.100.1.1C. 127.0.0.1D. 10.2.1.13



QUESTION 15You must configure an OSPF area that does not accept type 3 link-state advertisements (LSAs) from area 0 (other than the default route) You have configured yourarea to be stub, but you still see type 3 LSAs.

What will account for this behavior?

A. You should have configured your area as totally stubbyB. You should have used a not-so-stubby-areaC. You are experiencing a routing loopD. You have exported routes into OSPF

Correct Answer: ASection: OSPFExplanation


A totally stubby area is a stub area that receives only the default route from the backbone. ABRs do not flood LSA types 3, 4, or 5 into totally stubby areas.

QUESTION 16Router A is an OSPF router connected to both Area 0 and Area 1 Area 1 has been configured as a stub area Which two LSA types does Router A suppress fromArea 1 ?

A. Router LSAB. External LSA


C. Summary LSAD. ASBR Summary LSA

Correct Answer: BDSection: OSPFExplanation



In the exhibit, OSPF routers R1, R2, R3, and R4 come up, in order, at 1-minute intervals

Which router will be the designated router?.

A. R1B. R2C. R3D. R4

Correct Answer: ASection: OSPF


Explanation


The election of the very first designated router on a segment occurs within 40 seconds of the first device transmitting a hello packet. This wait time is honored everytime an election is held. When multiple devices boot within these 40 seconds the one with the higher priority will become the DR.


In the exhibit, how many full OSPF adjacencies will R3 have?

A. 0B. 1C. 2D. 3




DROther devices form a full state adjacency with both the DR and BDR. DROther devices form the two-way neighbor state with all other DROther devices.

QUESTION 19You want to configure support for an IPv6 environment In which hierarchy would you configure an OSPF area?

A. [edit protocols ospf-v6]B. [edit protocols ipv6-ospf]C. [edit protocols ipv6]D. [edit protocols ospf3]



A Junos device supports OSPFv3 configuration at the [edit protocols ospf3] hierarchy level. OSPFv3 supports both IPv4 and IPv6.

QUESTION 20Which three functions are performed by an OSPF area border router (ABR)? (Choose three)

A. flooding Summary LSAs to connected areasB. flooding ASBR Summary LSAs to connected areasC. generating all Router LSAs for connected neighborsD. performing summarization on routes headed to Area 0E. flooding NSSA External LSAs to Area 0

Correct Answer: ABDSection: OSPFExplanation


Summary LSAs describe IP prefixes learned from router and network LSAs. These LSAs are sent by the ABR attached to the area from where the prefixinformation was learned and sent to other OSPF areas (nterarea).

ASBR summary LSAs describe the router ID of ASBRs located in remote areas. These LSAs are sent by the ABR attached to the area in which the ASBR islocated to other OSPF areas (interarea).


In addition to adding new OSPF areas that restrict LSA flooding, you can also perform route summarization on the borders between OSPF areas.

QUESTION 21Your area border router (ABR) receives type 1.2 and 5 link-state advertisements (LSAs) from a non-backbone area.

What would the ABR do with the information learned from the non-backbone area?

A. The ABR will generate type 2 and 3 LSAs and flood type 5 LSAs to the backbone areaB. The ABR will generate only type 3 LSAs and flood only type 5 LSAs to the backbone areaC. The ABR will generate type 3 and 4 LSAs. And flood type 5 LSAs to the backbone areaD. The ABR will generate only type 4 LSAs and flood only type 5 LSAs to the backbone area



QUESTION 22After configuring OSPF between two routers you check for an adjacency. You see that the adjacencies are not coming up on an Ethernet segment.

What are two reasons that would cause this situation? (Choose two)

A. You have a mismatched IP subnet/maskB. Your hello timer intervals are mismatchedC. You are not using the same Junos version on each sideD. You priority values are mismatched



Fields in the OSPF hello packet that must match to form an adjacency include:

- Hello Interval


- Dead Interval- Network Mask (on broadcast media only)- Options (such as authentication settings, etc.)

QUESTION 23What is contained in an IS-IS CSNP message?

A. all of the headers of the LSPs in a router's link-state databaseB. all of the IP routes in a router's link-state databaseC. all of the IP routes in a router's routing tableD. all of the LSPs in a router's link-state database




Given the OSPF network topology shown in the exhibit, you would like to inject external (non-OSPF) routes into the network on Router D


Which two OSPF area types will support this configuration? (Choose two)

A. stub areaB. totally stubby areaC. not-so-stubby areaD. non-backbone area

Correct Answer: CDSection: OSPFExplanation


Any normal area (non-stub), allows the presence of AS external LSAs. A not-so-stubby-area (NSSA) allows external routes to be flooded within the area as well.


2bfc:0000:0000:0000:0217:cbff:fe8c:5c852bfc::0217:cbff:fe8c:5c852bfc:0:0:0:0217:cbff:fe8c:5c85

In the exhibit, three IPv6 addresses are listed. Which two statements are true? (Choose two.)

A. The first address is complete and correct.B. The third address is not formatted correctly.C. All three addresses are the same.D. The second address is incomplete and not correct.

Correct Answer: ACSection: OSPFExplanation


QUESTION 26What are two benefits of using an OSPF designated router (DR)? (Choose two.)


A. Reduces the size of the link-state database.B. Reduces LSA flooding on a broadcast segment.C. Reduces LSA flooding throughout an OSPF area.D. Reduces router resources used.



Using a designated router to represent the broadcast link can significantly reduce traffic on the segment. As a result it reduces the amount of resources used.

QUESTION 27You notice that the RID of your router is being taken from the address of your management interface.

What could cause this scenario?

A. The loopback address was configured with a /32 address.B. The loopback address was not configured under [edit protocols ospf].C. A suitable loopback address was not configured on the router.D. The loopback address was configured under [edit routing-options].



If you do not manually define a RID, the Junos OS uses one fo the IP addresses configured on the device at the time of the OSPF process starts. If the loopbackinterface is configured with a non-127/8 IP address, the Junos OS uses that address first. If a loopback interface is not configured, the Junos OS uses the nextsuitable address, typically the dedicated management interface.

QUESTION 28R8 is an OSPF router connected to both Area 0 and Area 2. Area 2 has been configured as a totally stubby area. Which three LSA types does R8 suppress fromArea 2? (Choose three.)

A. Router LSA


B. Network LSAC. External LSAD. Summary LSAE. ASBR Summary LSA

Correct Answer: CDESection: OSPFExplanation


A totally stubby area is a stub area that receives only the default route from the backbone. ABRs do not flood LSA types 3, 4, or 5 into totally stubby areas.

QUESTION 29You have a stub OSPF area running in your network. Your supervisor has asked you to build a virtual link across this area to connect new equipment acquired in arecent ISP acquisition. Which statement is correct about this scenario?

A. Type 5 LSAs would be blocked in a stub area.B. Type 5 LSAs would carry external information across your transit area to the backbone.C. Type 5 LSAs would be seen only in the newly attached area.D. Type 5 LSAs would be converted to type 7 LSAs.



QUESTION 30You have two OSPF routers that are trying to form an adjacency. When you issue the command show ospf neighbor, you see that one router is in the loading stateand the other is in the full state.Why are you seeing the router's state as loading?



A. The router does not know about the received LSA header and has transmitted a link-state request.B. The router has finished transmitting, but is still receiving database information.C. The router is waiting for a start event.D. The router has established bidirectional communication with its peer.




[edit policy-options]user@r1# showpolicy-statement to-OSPF { term match-direct-route { from { protocols direct; route-filter 172.18.1.0/24 exact; } then accept; }}

[edit protocols]user@r1# showospf { export to-ospf; area 0.0.0.1; interface ge-1/0/0.0; interface lo0.0; }}

The policy shown in the exhibit has been configured and installed on your router.

What is the result of applying this policy?


A. The 172.18.1.0/24 network will be redistributed into OSPF as an external route.B. The 172.18.1.0/24 network will be redistributed into OSPF as an internal route.C. The 172.18.1.0/32 network will be redistributed into OSPF as an external route.D. The 172.18.1.0/32 network will be redistributed into OSPF as an internal route.



External (type 5): External LSAs describe IP prefixes redistributed from other routing protocols, such as RIP, BGP, or even static routes. These routing prefixes areexported into OSPF via a routing policy and are considered AS external routes from the perspective of the OSPF protocol.

QUESTION 32You are asked to deploy OSPF between two routers over a broadcast medium.

Which three fields in the OSPF hello packet must match? (Choose three.)

A. hello intervalB. optionsC. backup designated routerD. network maskE. designated router

Correct Answer: ABDSection: OSPFExplanation


QUESTION 33Which statement is correct about OSPF Type 7 LSAs?

A. They are converted into Type 5 LSAs by the ASBR.B. They are converted into Type 5 LSAs by the ABR.C. They are converted into Type 3 LSAs by the ABR.


D. They are converted into Type 4 LSAs by the ABR.



QUESTION 34What are two destination addresses used for OSPF link-state update packets? (Choose two.)

A. 224.0.0.1B. 224.0.0.4C. 224.0.0.6D. 224.0.0.5

Correct Answer: CDSection: OSPFExplanation


QUESTION 35R1 is an OSPF router with a priority of 100 and has been elected as the designated router (DR). R2 is the backup designated router (BDR) with a priority of 50. Athird router, R3, comes online with a priority of 200.

Which routers will be the DR and BDR after R3 comes online?

A. R1 will be the DR and R2 will be the BDR.B. R3 will be the DR and R1 will be the BDR.C. R2 will be the DR and R1 will be the BDR.D. R3 will be the DR and R1 will be the BDR.




Explanation:


Referring to the exhibit, which two statements are correct about R2? (Choose two.)

A. If R2 remains in the ExStart state, then you should verify the MTU setting on R2 and R3.B. R2 LSDB is synchronized with R1.C. If R2 remains in the ExStart state, then you should verify Physical Layer and Data Link Layer connectivity on R2 and R3.D. R2 LSDB is not synchronized with R1.



QUESTION 37You are asked to deploy OSPF between two routers over a point-to point link.

Which three fields in the OSPF hello packet must match? (Choose three.)

A. network maskB. hello intervalC. options


D. dead intervalE. backup designated router

Correct Answer: BCDSection: OSPFExplanation


QUESTION 38On an Ethernet segment, OSPF DROther routers from which type of adjacency with each other?

A. FullB. 2WayC. ExStartD. Exchange



QUESTION 39To which OSPF state does a device transaction once it receives an initial hello packet?

A. 2WayB. FullC. ExStartD. Exchange




QUESTION 40Your area boarder router (ABR) receives type 1, 2, and 5 link-state advertisements (LSAs) from a nonbackbone area. What would the ABR do with the informationlearned from the nonbackbone area?

A. It will generate type 2 and 3 LSAs and flood type 5 LSAs to the backbone areaB. It will generate only type 3 LSAs and flood only type 5 LSAs to the backbone areaC. It will generate type 3 and 4 LSAs, and flood type 5 LSAs to the backbone areaD. It will generate only type 4 LSAs and flood only type 5 LSAs to the backbone area



Summary LSAs describe IP prefixes learned from router and network LSAs. These LSAs are sent by the ABR attached to the area from where the prefixinformation was learned and sent to other OSPF areas (interarea). ASBR summary LSAs describe the router ID of ASBRs located in remote areas. These LSAsare sent by the ABR attached to the area in which the ASBR is located to other OSPF areas (interareas). External LSAs are flooded to all OSPF areas except areasdefined as stub areas.

QUESTION 41You are troubleshooting an adjacency formation problem in OSPF using traceoptions. Which command is used to view the output of a traceoptons file called trace-ospf?

A. show log trace-ospfB. file show /log/trace-ospfC. monitor trace-ospfD. show system syslog



The trace output (debug information) is directed to the named log file, which is stored in the /var/log directory. You can view the output as a log file using the "showlog" command, or in real-time using the "monitor start" command


QUESTION 42You have been asked to use an interior gateway protocol (IGP) to design your network. You have been told that your design should allow for fast reconvergenceand scalability for future growth. Which IGP would accommodate these criteria?

A. static routingB. Routing Information Protocol (RIP)C. Open Shortest Path First (OSPF)D. Border Gateway Protocol (BGP)



Static routing is static and not a protocol. BGP is an EGP rather than an IGP. OSPF has a faster convergence due to its link-state architecture compared to RIP,which is a distance vector protocol.

QUESTION 43R3 is an OSPF router connect to both Area 0 and Area 1. Area 1 has been configured as a stub area. Which two LSA types does R3 suppress from Area 1?(Choose two.)

A. Router LSAB. External LSAC. Summary LSAD. ASBR Summary LSA



Stub areas are areas through which, or into which, AS external advertisements are not flooded (LSA types 4 and 5).

QUESTION 44What is the purpose of the designated router in OSPF?


A. to connect a stub area to the backbone areaB. to connect a totally stub area to the backbone areaC. to form adjacencies with other OSPF routers in a backbone areaD. to form adjacencies with other OSPF routers in a broadcast domain



It is the designated router's job to form an adjacency with all other OSPF routers on the link and to advertise the link-state information to the AS.

QUESTION 45Your OSPF network design uses stub areas extensively due to 5000 external routes within the backbone and resource constraints in the nonbackbone areas. Younow have a device in Area 2 that must perform as an ASBR. Which OSPF area types should you use for Area 2?

A. stubB. non-backbone areaC. not-so-stubby-areaD. totally stubby area



An OSPF stub area has no external routes in it, so you cannot redistribute routes from another protocol into a stub area. A not-so-stubby-area (NSSA) allowsexternal routes to be flooded within the area. These routes are then leaked into other areas. However, external routes from other areas still do not enter the NSSA.(ABR does not flood LSA types 4 and 5 into an attached NSSA.)

QUESTION 46Your OSPF network is currently operating with a single backbone area and you are concerned with the scalability of your design.

Which network design is a best practice for providing the scalability you desire?


A. Eliminate all designated routersB. Implement areas in your networkC. Reduce the database refresh timer valueD. Allow each device to perform ASBR duties



Using OSPF, you can segment an AS into smaller groups referred to as areas. Using areas achieves an OSPF hierarchy that can facilitate growth and scalability.

QUESTION 47Which configuration parameter allows a Junos device to include an interface route into OSPF while prohibiting adjacencies from forming?

A. inactiveB. no-peer-advertiseC. disableD. passive



To include an interface route into OSPF as an internal OSPF route while prohibiting adjacency formation for that interface, you should include the interface underthe [edit protocols ospf area area-number] hierarchy level along with the passive configuration option.



Given the OSPF topology shown in the exhibit, how many unique link-state databases are present in the network?

A. 1B. 2C. 3D. 6



Each OSPF router maintains a separate LSDB for each area to which it is connnected.

QUESTION 49You have been asked to provide three commands helpful in troubleshooting OSPF adjacencies.

Which three commands would be helpful? (Choose three.)

A. show ospf databaseB. show ospf summary


C. show ospf interfaceD. show ospf adjacencyE. show ospf neighbor

Correct Answer: ACESection: OSPFExplanation


show ospf database, interface, and neighbor would provide detailed information about the OSPF database, interfaces running OSPF, and information about theOSPF neighbors. show ospf summary only provides a high-level information, while show ospf adjacency does not exist.

QUESTION 50Two Junos devices are trying to form an OSPF adjacency. When you issue the "show ospf neighbor" command, you see that one device is in the Loading state andthe other is in the Full state. Why is one device in the Loading state?


A. The device does not know about the received LSA header and has transmitted a link-state requestB. The device has finished transmitting, but is still receiving database informationC. The device is waiting for a start eventD. The device has established bidirectional communication with its peer



The Loading state indicates that a device has finished transmitting its database to its peer but is still receiving database information from the neighboring device.


ISIS

QUESTION 1Which two statements correctly describe IS-IS adjacencies? (Choose two.)

A. Level 1 adjacencies can form in the same (intra) area only.B. Level 2 adjacencies are formed between (inter) areas only.C. Level 2 adjacencies can be established either interarea or intra-area.D. Level 2 adjacencies can form within the same (intra) area only.

Correct Answer: ACSection: ISISExplanation


QUESTION 2Which IS-IS PDU is used to request a retransmission of a missing link-state packet?

A. the complete sequence number PDUB. the partial sequence number PDUC. a hello PDU with a request PDU TLV specifying the missing LSPD. a hello PDU with a refresh PDU TLV requesting all LSPs

Correct Answer: BSection: ISISExplanation


QUESTION 3Which statement is true regarding the IS-IS designated intermediate system (DIS)?

A. The DIS function is used only on broadcast or multi-access networks.B. The DIS function is used on both broadcast and point-to-point link types.C. On a broadcast network, adjacencies are formed only between the non-DIS nodes and the DIS to help reduce adjacency overhead.D. IS-IS supports a backup DIS mechanism to provide rapid failover in the event of a DIS failure.


Correct Answer: ASection: ISISExplanation


QUESTION 4You want to establish an IS-IS Level 1 adjacency between two routers. The adjacency is not forming.

Which three reasons would account for this issue? (Choose three.)

A. A lack of or a malformed ISO network entity title (NET) on the loopback interface would cause this issue.B. The interface MTU might be less than 1492.C. The IS-IS protocol on the loopback interface has not been enabled.D. The area IDs might be matched and should be set differently.E. An ISO NET might not be configured on the physical interface.

Correct Answer: ABCSection: ISISExplanation


QUESTION 5Which three statements are true regarding the IS-IS link-state database (LSDB)? (Choose three.)


A. An L1 router has a single database reflecting the connectivity of its area.B. An L1 router often relies on a default route generated by attached routers to reach interarea destinations.C. The Level 2 database contains only backbone area routes unless route leaking is configured.D. Route leaking can be used to optimize Level 2 to Level 1 routing.E. An attached router has at least two LSDBs: one for each Level 1 area and a single LSDB for the Level 2 backbone.


Correct Answer: ABESection: ISISExplanation


QUESTION 6Which PDU type is sent by an IS-IS router when it detects that its link-state database is out of date?

A. helloB. link stateC. complete sequence numberD. partial sequence number

Correct Answer: DSection: ISISExplanation


QUESTION 7What are two similarities between OSPF and IS-IS? (Choose two.)

A. Both use hello packets to form and maintain adjacencies.B. Both use the Dijkstra algorithm to construct a shortest-path tree.C. Both elect a designated router and a backup designated router.D. Both have a built-in mechanism to provide address summarization between areas.

Correct Answer: ABSection: ISISExplanation




protocols { isis { level 1 disable; interface ge-1/0/0.0 { level 2 disable; } interface ge-1/1/0.0; interface lo0.0; }}


Referring to the exhibit, what is the resulting behavior on interface ge-1/0/0?

A. Level 1 is enabled.B. Level 1 is disabled.C. Level 2 is enabled.D. Level 1 and Level 2 are disabled.




[edit]user@router# run show isis interfaceIS-IS interface database:Interface L CirID Level 1 DR Level 2 DR L1/L2 Metricge-1/0/2.0 3 0x1 router.00 router.00 10/10lo0.0 0 0x1 Passive Passive 0/0


Referring to the exhibit, which two statements are true regarding the GE interface? (Choose two.)


A. It operates at both Level 1 and Level 2.B. It operates at Level 3, which supports hierarchical backbone areas.C. The local router is the IS-IS designated intermediate system at all levels.D. The local router is the IS-IS designated router at all levels.




user@R2> show

protocols { isis { export leak; interface ge-1/1/0.0; interface ge-1/1/1.0 { level 1 disable; } interface lo0.0; }}policy-options { policy-statement leak { term 1 { from level 1; to level 2; then accept; } }}


R1 and R2 have a Level 1 IS-IS adjacency. R2 participates in both Level 1 and Level 2, and is receiving routes from a Level 2 neighbor. A policy on R2 has beencreated to leak routes to Level 1, but R1 is not receiving the routes.


Referring to the exhibit, what is the solution on R2?

A. The policy must be applied as an export policy at the interface level.B. The policy must be changed to include from protocol isis.C. The policy must be changed to specify from level 2 and to level 1.D. The policy must be applied as an import policy.

Correct Answer: CSection: ISISExplanation



user@R1> show

interfaces { ge-1/1/0 { unit 0 { family inet { address 10.100.1.1/30; } family iso; } } lo0 { unit 0 { family inet { address 10.100.10.1/32; } family iso { address 49.1001.0010.0100.00; } } }}protocols {


isis { interface ge-1/1/0.0 { level 2 disable; } interface lo0.0; }}

user@R2> show

interfaces { ge-1/1/0 { unit 0 { family inet { address 10.100.1.2/30; } } } lo0 { unit 0 { family inet { address 10.100.10.2/32; } family iso { address 49.1001.0010.0200.00; } } } }protocols { isis { interface ge-1/1/0.0; interface lo0.0; }}


Referring to the exhibit, R1 and R2 are directly connected using interface ge-1/1/0.

What happens as a result of the configurations?


A. No adjacency formsB. Level 2 adjacency formsC. Level 1 adjacency formsD. Level 1 and Level 2 adjacencies form




user@R1> show

interfaces { ge-1/1/0 { unit 0 { family inet { address 10.100.1.1/30; } family iso; } } lo0 { unit 0 { family inet { address 10.100.10.1/32; } family iso { address 49.1001.0010.0100.00; } } }}protocols { isis { level 1 disable; interface ge-1/1/0.0 {


level 2 disable; } interface lo0.0; }}

user@R2> show

interfaces { ge-1/1/0 { unit 0 { family inet { address 10.100.1.2/30; } family iso { mtu 1496; } } } lo0 { unit 0 { family inet { address 10.100.10.2/32; } family iso { address 49.1002.0010.0200.00; } } }}protocols { isis { interface ge-1/1/0.0 { level 2 disable; } interface lo0.0; }}


Referring to the exhibit, R1 and R2 are directly connected using interface ge-1/1/0.


What is the reason the IS-IS adjacency fails?

A. R2 has an MTU value of 1496 configured on ge-1/1/0.B. R2 and R1 have different area IDs.C. R1 is configured for Level 2, and R2 is configured for Level 1.D. R1 is configured for both Level 1 and Level 2 to be disabled.



QUESTION 13Which IS-IS packet is used to determine the level of an IS-IS neighbor?

A. IIHB. LSPC. PSNPD. CSNP



IS-IS Hello packets are used to discover neighbors and they also determine the level fo the peer.



An operator is unable to establish any IS-IS adjacencies on a router in the network.

Based on the configuration shown in the exhibit, what is the problem?

A. Interface loO must be configured in the IS-IS hierarchyB. Each network interface needs a unique family ISO address


C. The IS-IS level for an each interface must be specifiedD. The ISO address for interface loO is not in hex format



QUESTION 15Your company has purchased two new Juniper Networks MX480 routers. Your manager has asked you to add these two devices to the existing ISIS network.

Which two rules about ISIS adjacencies must you consider when carrying out the configuration? (Choose two)

A. For Level 1 adjacencies, area IDs must be the sameB. For Level 2 adjacencies area IDs must be the sameC. The IS-IS levels configured on the interfaces must be the sameD. The IS-IS levels on the interfaces can be different



IS-IS adjacencies can only form when the level is the same for both peers. Also for Level 1, the neighbor must be in the same area.


You have two Junos devices connected over a Gigabit Ethernet link as shown in the exhibit. It is required that an IS-IS adjacency be established without the needfor a designated intermediate system (DIS)


Which configuration statement entered on both routers will achieve this goal?

A. set interface ge-0/0/2 unit 0 family iso no-disB. set interface ge-0/0/2 unit 0 family iso point-to-pointC. set protocols isis interface ge-0/0/2.0 no-disD. set protocols isis interface ge-0/0/2.0 point-to-point



In IS-IS protocol a default interface type fo broadcast is set on Ethernet interfaces, which means that the determination of a DIS is required. To get around this, anadministrator can set the Ethernet's logical interface to point-to-point at the [edit protocols isis] hierarchy level.


protocols { isis { level 1 disable; interface ge-0/0/0.100 { level 2 disable; } interface all; interface fxp0.0 { disable; } }}

Based on the configuration shown in the exhibit, what will be the state of the IS-IS levels on interface ge-0/0/0.100?

A. Level 1 is enabled and Level 2 is disabled.B. Level 1 is disabled and Level 2 is enabled.C. Level 1 is enabled and Level 2 is enabled.D. Level 1 is disabled and Level 2 is disabled.




In the configuration, Level 1 is disabled globally for all interfaces and Level 2 is specifically disabled for ge-0/0/0.100. As a result, both levels are disabled forinterface ge-0/0/0.100.

QUESTION 18Which packet type does a Junos device use to request up-to-date link-state information?




With IS-IS, a partial sequence number PDU (PSNP) performs a similar function as a Link State Request packet does in OSPF, which is to request link-state data.



What does IS-IS/18 mean in the output displayed in the exhibit?

A. These routes are internal Level 1 routes.B. These routes are internal Level 2 routes.C. These routes are external Level 1 routes.D. These routes are external Level 2 routes.



The default IS-IS route preferences are:- Level 1 internal - 15- Level 2 internal - 18- Level 1 External - 160- Level 2 External - 165

QUESTION 20In an IS-IS network, which device represents the pseudonode?

A. a designated intermediate systemB. an area border routerC. a router with an IS-IS export policyD. a router connected to the backbone




On broadcast networks in the IS-IS protocol, the elected DIS creates the pseudo-node, which represents itself and advertises it into the network at the appropriatelevel.

QUESTION 21Which type of router can provide connectivity between areas in an IS-IS domain?

A. a Level 1 router with adjacencies within a single areaB. a Level 2 router with adjacencies in more than one areaC. an area border router with adjacencies in more than one areaD. a Level 2 router with adjacencies in a single area



inter-area connectivity is provided by Level 2 routers with connectivity into multiple areas

QUESTION 22Which IS-IS packet is used to carry routing updates?





Link-state PDUs (LSPs) area used to carry link-state update information in IS-IS protocol.


interfaces { ge-0/0/0 { vlan-tagging; unit 100 { vlan-id 100; family inet { address 192.168.100.97/30; } family iso; } } unit 200 { vlan-id 200; family inet { address 192.168.100.94/30; } family iso; } } } fxp0 { description "MGMT INTERFACE - DO NOT DELETE"; unit 0 { family inet { address 10.210.10.11/27; } } } lo0 { unit 0 { family inet { address 192.168.100.1/32; } family iso { address 49.1111.1921.6801.0001.00;


} } } }protocols { isis { interface ge-0/0/0.100; interface ge-0/0/0.200; }}


An operator is unable to establish any IS-IS adjacencies on a router in the network.

Based on the configuration shown in the exhibit, what is the problem?

A. Interface lo0 must be configured in the IS-IS hierarchy.B. Each network interface needs a unique family ISO address.C. The IS-IS level for an each interface must be specified.D. The ISO address for interface lo0 is not in hex format.




protocols { isis { interface lo0.0; interface ge-0/0/0.100; }}

Referring to the exhibit, what will be the IS-IS levels enabled on the interface ge-0/0/0.100?


A. Level 1 onlyB. Level 2 onlyC. Level 1 and Level 2D. Level 1, Level 2, and Level 3



When configuring interfaces in the IS-IS protocol, if no level is explicitly assigned then the default is to enable both Level 1 and Level 2.

QUESTION 25A IS-IS TLV includes which two attributes? (Choose two.)

A. topologyB. vectorC. lengthD. value

Correct Answer: CDSection: ISISExplanation


QUESTION 26Which two routing protocols make use a designated router, or pseudo node, to represent a broadcast network? (Choose two.)

A. BGPB. OSPFC. MPLSD. IS-IS

Correct Answer: BDSection: ISIS


Explanation



Referring to the exhibit, what is required to establish an IS-IS adjacency between these two routers?

A. The interface connecting the two routers must be configured as a Level 2 interface.B. Both routers will require wide metrics to be enabled.C. The interface connecting the two routers must be configured as a Level 1 interface/D. Router A must be configured as the designated intermediate system (DIS).



QUESTION 28You are asked to deploy a large-scale IS-IS network with multiple areas.


A. A collection of Level 1 routers in different areas constitute the backbone in the network.B. Level 2 routers can route between areas.C. Level 1 routers can route between areas.D. A collection of Level 2 routers in different areas constitute the back bone in the network.

Correct Answer: BD


Section: ISISExplanation



In the exhibit, which configuration is required to establish a single adjacency between the two IS- IS routers?

A. set protocols isis interface xe-0/0/0.0 point to pointB. set protocols isis level 2 wide-metrics-onlyC. set protocols isis interface xe-0/0/0.0 level 1 disableD. set protocols isis interface xe-0/0/0.0 level 1 priority 0



QUESTION 30In an IS-IS network, Router A is the current DIS with a priority of 64. Router B comes online with a priority of 100.

In this scenario, which statement is correct?

A. Router A remains as the DIS.B. Router A remains the DIS and Router B becomes the backup DIS.C. Router B becomes the DIS.D. Router B becomes the DIS and router A becomes the backup DIS.





An ISO NET has been configured on R2's lo0.0 interface and ge-0/0/2.0 has been configured to run IS-IS. However, IS-IS adjacency on ge-0/0/2.0 is not comingup.

Referring to the exhibit, what is required to enable IS-IS?

A. Configure the family iso parameter under the ge-0/0/2.0 interface.B. Disable Level 2 for interface ge-0/0/2.0C. Add the lo0.0 interface under the [edit protocols isis] hierarchy.D. Configure the interface priority for ge-0/0/2.0.



QUESTION 32


You are asked to deploy a large-scale IS-IS network with multiple areas.

In this scenario, which statement is true?

A. A router configured for Level 1 only informs all Level 2 routers in the area of external reachability.B. A router configured for Level 1 and Level 2 informs all Level 2 routers in the area of external reachability.C. A router configured for Level 2 only informs all level 1 routers in the area of external reachability.D. A router configured for Level 1 and Level 2 informs all Level 1 routers in the area of external reachability.




Referring to the exhibit, four IS-IS routers have been deployed on a multi-access Ethernet segment. Router C came online first.

After all routers are online, which two statements are true? (Choose two.)


A. Adjacencies are only formed with designated intermediate system (DIS).B. Router D is the designated intermediate system (DIS).C. Adjacencies are formed between all four routers.D. Router C is the designated intermediate system (DIS).

Correct Answer: BCSection: ISISExplanation


QUESTION 34You are deploying IS-IS in your network to enable the routing of only IPv6. Assume that the loopback interface has been properly configured.

What is the minimum required configuration to enable only IPv6 routing in IS-IS?

A. user@host# show protocols isisrib-group inet6;interface ge-0/0/0.0;interface lo0.0 {passive;}user@host# show interfaces ge-0/0/0unit 0 {family inet6 address fd85:5944:1aee:026::1/64;}

B. user@host# show protocols isisinterface ge-0/0/0.0;interface lo0.0 {passive;}user@host# show interfaces ge-0/0/0unit 0 {family iso;family inet6 address fd85:5944:1aee:026::1/64;}

C. user@host# show protocols isisno-ipv4-routing;interface ge-0/0/0.0


interface lo0.0 {passive;}user@host# show interfaces ge-0/0/0unit 0 {family iso;family inet6 address fd85:5944:1aee:026::1/64;}

D. user@host# show protocols isisno-ipv4-routing;interface ge-0/0/0.0;interface lo0.0 {passive;}user@host# show interfaces ge-0/0/0unit 0 {family iso;family inet6;}

E. user@host# show protocols isistraffic-engineering {family inet6 {shortcuts;}}interface ge-0/0/0.0;interface lo0.0 {passive;}user@host# show interfaces ge-0/0/0unit 0 {family inet6 address fd85:5944:1aee:026::1/64;family iso;}




QUESTION 35What are three IS-IS PDU types? (Choose three.)

A. type length valueB. link-stateC. partial sequence numberD. database descriptionE. complete sequence number

Correct Answer: BCESection: ISISExplanation


QUESTION 36What are three circumstances under which a router sends link-state PDUs (LSPs)? (Choose three)

A. LSPs are sent periodically every 9 secondsB. LSPs are sent when there is a network changeC. LSPs are sent during adjacency formationD. LSPs are sent in response to CSNP messagesE. LSPs are sent in response to PSNP messages

Correct Answer: BCESection: ISISExplanation


Link-state PDUs are sent as a response to a link-state request with a PSNP and during the formation of an IS-IS neighbor relationship. They are also sent as atriggered event when network changes occur.

QUESTION 37Which two IS-IS packet types are used to maintain IS-IS database synchronization? (Choose two.)

A. IIH


B. LSPC. PSNPD. CSNP

Correct Answer: CDSection: ISISExplanation


Periodically, a designated intermediate system (DIS) will send CSNPs, which are a summary of its LSDB, to maintain database synchronization with other IS-ISrouters attached to the LAN. If a device has different information in its LSDB than advertised in the CSNP, it will send a PSNP requesting the specific link-statedata.


In the exhibit, Router A and Router B are operating on the LAN with Router B acting as the designated intermediate system (DIS).

When Router C and Router D are added to the LAN, which statement is true?


A. Router C becomes the new DIS with no backup DISB. Router D becomes the new DIS with no backup DISC. Router C becomes the new DIS with Router B as the backup DISD. Router D becomes the new DIS with Router A as the backup DIS



In IS-IS, DIS elections are deterministic, which means that if a device with a higher priority is added to the LAN it will take over as the DIS. Unlike OSPF, there is nobackup DIS.

QUESTION 39By default, what is the maximum metric that can be advertised for any interface in IS-IS?

A. 1B. 10C. 63D. 1023



By default, any single link can have a maximum metric value of 63. Wide metrics allow for higher metric values, and can be enabled on a per-level basis.

QUESTION 40In the Junos OS, where do you configure the area value for IS-IS?

A. [edit protocols isis level 2]B. [edit routing-options]C. [edit protocols isis level 1]D. [edit interfaces lo0]




To enable IS-IS on a Junos device, one of the parameters you must configure is the network entity title (NET), which is usually set on the lo0 interface. The NETcontains the area ID, system ID, and selector.

QUESTION 41By default, how often does a designated intermediate system (DIS) send IS-IS hello messages on a LAN?

A. every 3 secondsB. every 9 secondsC. every 10 secondsD. every 30 seconds



The default time period for most IS-IS hellos is every 9 seconds, however a DIS sends them every 3 seconds.



Referring to the network illustrated in the exhibit, how does R1 reach destinations in Area 49.2222?

A. It uses the routes from Area 49.2222, which it learns from R2B. It sees the attached bit from R2 and creates a default routeC. It must have a default route manually configuredD. It receives a default route in the IS-IS update from R2



When an IS-IS Level 1 router discovers that its neighbor has inter-area connectivity because the attached bit is set, it automatically creates a default route with that peer as the next hop.


user@router> show isis database


IS-IS level 2 link-state database:LSP ID Sequence Checksum Lifetime AttributesTokyo.00-00 0x6 0xb978 1154 L1 L2host.00-00 0x4 0x140c 1154 L1 L2Wash-DC.00-00 0x1d7 0x7f37 683 L1 L2Beijing.00-00 0x1d3 0xe603 1024 L1 L2Beijing.02-00 0x9 0xea81 1175 L1 L2Amsterdam.00-00 0x1c8 0x8b1c 677 L1 L2Cairo.00-00 0x1ca 0x1571 1103 L1 L2Sydney.00-0 0x1dd 0x178a 779 L1 L2 8 LSPs

The exhibit displays the output of the command "show isis database" on a Junos device. Why are there two entries for the Beijing device?

A. There are two devices in the network with the host name Beijing; this problem should be repairedB. The Beijing device is routing both IPv4 and IPv6C. The Beijing device is a designated intermediate system (DIS)D. The Beijing device is going through a graceful restart



All IS-IS routers enabled for a given level generate an LSP that is present in the LSDB. The pseudo portion is always 00. If a DIS exists, that device will advertise anadditional LSP representing 'the network'. with a value other than 00, such as 01 or 02.

QUESTION 44Which command will display the number of IS-IS packets sent and received on a Junos device?

A. show isis packetsB. show isis spf logC. show isis statisticsD. show isis exchanges




The "show isis statistics" command verifies whether the device is sending and receiving IS-IS packets.

QUESTION 45How can you control the selection of the designated intermediate system (DIS) on a specific link in an IS-IS network?

A. Configure the interface as passiveB. Configure a priority on the interfaceC. Configure the hello interval on the interfaceD. DIS selection is random in the Junos OS



The highest priority (and then highest MAC address) is the criterion used to select the DIS. This priority is set on the interface in the IS-IS protocol configuration.

QUESTION 46Which statement correctly describes the metric used for IS-IS?

A. The IS-IS metric is calculated based on a reference bandwidth of 10 Mbps by defaultB. By default, IS-IS interface routes are assigned a metric of 10, regardless of actual link speedC. By default, the Junos OS sends only wide metrics to allow any single link to have a metric as high as 63D. For proper operation, the same metric value should be specified at both ends of an IS-IS link



The protocol IS-IS does have an ability to use reference bandwidth to dynamically calculate link costs, but the default behavior has a value of 10 assigned to alltransit interfaces.


QUESTION 47Which statement is true regarding IS-IS?

A. IS-IS PDUs are also known as LSAsB. IS-IS PDUs are transmitted at Layer 3C. All IS-IS routers run a single routing algorithmD. IS-IS PDUs are hosts that send and receive packets



Once IS-IS adjacencies are formed, the devices will run the Shortest Path First algorithm to build a shortest path tree to determine the least cost path to destinationnetworks and devices.

QUESTION 48What is the default metric for IS-IS interfaces?

A. 1B. 10C. it depends on the bandwidthD. it depends on the link type



The default metric of an IS-IS transmit interface is 10



In the exhibit, R3 and R4 have the level 2 disable statements applied to their global IS-IS configuration

Which two statements are true regarding R2?

A. R2 has a Level 1 adjacency with R1B. R2 has a Level 2 adjacency with R1C. R2 has a Level 1 adjacency with R4D. R2 has a Level 2 adjacency with R4

Correct Answer: BCSection: ISISExplanation


To form IS-IS adjacencies between Level 1 routers, devices must have Level 1 enabled on their facing interfaces. To form adjacencies with devices in other areas,the facing interfaces must be configured for Level 2.

QUESTION 50What is contained in an IS-IS CSNP message?



A. all of the headers of the LSPs in a device's link-state databaseB. all of the IP routes in a device's link-state databaseC. all of the IP routes in a devices's routing tableD. all of the LSPs in a device's link-state database



Periodically, IS-IS routers will generate CSNPs for database synchronization. These packets contain summary contents of the sender's LSDB in the form of LSPheaders.


BGP

QUESTION 1Which three statements correctly describe IBGP and EBGP interaction? (Choose three.)


A. IBGP is used within an AS, whereas EBGP is used between two different ASs.B. EBGP peering is normally loopback-based to provide tolerance for interface or link failures.C. By default, EBGP updates the next-hop attribute, whereas IBGP does not.D. IBGP speakers can re-advertise IBGP-learned or EBGP-learned routes to other IBGP speakers.E. EBGP speakers can re-advertise IBGP-learned or EBGP-learned routes to other EBGP speakers.

Correct Answer: ACESection: BGPExplanation


QUESTION 2Which two statements correctly describe how the AS path attribute is used by BGP? (Choose two.)

A. The AS path attribute is updated whenever an EBGP-learned route is re-advertised using IBGP.B. The AS path attribute is updated in EBGP advertisements only and is the primary loop- avoidance mechanism for BGP.C. When local preference is the same, the AS path attribute is a common tiebreaker, where paths with fewer AS hops are preferred.D. When local preference is the same, the AS path attribute is a common tiebreaker, where paths with more AS hops are preferred.

Correct Answer: BCSection: BGPExplanation


QUESTION 3Which statement describes the role of local preference in the BGP route selection process?


A. Local preference is evaluated early in the BGP route selection process and results in the route with the highest numerical local preference being selected.B. Local preference is evaluated early in the BGP route selection process and results in the route with the lowest numerical local preference being selected.C. Local preference is used to break ties when all other received BGP attributes are otherwise equal.D. Local preference is sent by an EBGP speaker to a neighboring AS in an attempt to influence how the remote peer's traffic will ingress into your network.

Correct Answer: ASection: BGPExplanation


QUESTION 4Which three BGP attributes are used for loop prevention? (Choose three.)

A. AS pathB. originator IDC. next hopD. cluster listE. origin

Correct Answer: ABDSection: BGPExplanation


QUESTION 5You are attempting to influence return traffic into your autonomous system by preferring one router as an entry point.

Which two BGP attributes will affect this behavior? (Choose two.)

A. originator IDB. local preferenceC. AS pathD. MED


Correct Answer: CDSection: BGPExplanation


QUESTION 6Which three BGP attributes must be sent to EBGP peers? (Choose three.)

A. local preferenceB. atomic aggregatorC. originD. next hopE. AS path

Correct Answer: CDESection: BGPExplanation


QUESTION 7What is a valid BGP neighbor state?

A. OpenEstablishedB. OpenConnectC. OpenConfirmD. OpenActive

Correct Answer: CSection: BGPExplanation


QUESTION 8Which statement is true regarding BGP?


A. Using BGP within your AS eliminates the need for an IGP.B. EBGP sessions have a TTL value of 64 by default.C. If an EBGP peer is more than one hop away, a multihop BGP session must be established.D. BGP devices require a direct connection to peer with each other.



QUESTION 9A route to the same destination is received from two different BGP sources.

Which criterion is considered first to determine the active BGP route?

A. cluster lengthB. AS-path lengthC. lowest RIDD. local preference

Correct Answer: DSection: BGPExplanation


QUESTION 10You are troubleshooting a BGP-learned prefix that is not being installed in the routing table.

Which command shows you the missing route?

A. show route advertising-protocol bgpB. show route stateC. show route hidden extensiveD. show bgp summary




QUESTION 11You are asked to configure a new external BGP connection to a peer's loopback interface. You verify that the peer's loopback interface is reachable, but the BGPconnection remains in Idle state.

Which BGP parameter is required to establish the BGP connection?

A. multipathB. multihopC. as-overrideD. advertise-inactive

Correct Answer: BSection: BGPExplanation



{master}[edit]user@router-RE0# run show task replicationStateful Replication: EnabledRE mode. MasterProtocol Synchronization StatusOSPF CompleteRIP CompleteBGP CompleteMPLS CompleteLDP Complete

{master}[edit]


user@router-RE0# run show bgp summary | match 192.168.1.1192.168.1.1 65056 288 327 0 2 1:05 Establ

{backup}[edit]user@router-RE1# run show system switchoverGraceful switchover: OnConfiguration database. ReadyKernel database. ReadyPeer state. Steady State

{backup}[edit]user@router-RE1# run show bgp summary | find 192.168.1.1192.168.1.1 65056 592 737 3778 2 1:33 Establ

{backup}[edit]user@router-RE1# run show bgp replicationSynchronization master:Session state. Up, Since. 6d 20:42:51Flaps: 1, Last flap reason: Commit-sync errorProtocol state. Idle, Since. 5d 19:41:52Synchronization state. CompleteNumber of peers waiting. AckWait: 0, SoWait: 0, ScheduleD. 0rsync walk at: inet.0 - , queued 0Messages sent: Open 1, Establish 7415, Update 17, Error , Complete 48Messages received. Open 1, Request 1 wildcard 47 targeted, EstablishAck 2827, CompleteAck 4


Referring to the exhibit, which statement is correct?

A. An RE switchover is likely to result in BGP disruption, but no dataplane impact will be seen.B. An RE switchover is likely to result in BGP disruption which will also effect the dataplane.C. The system is not yet GRES ready, you need to wait for kernel synchronization to complete.D. The system is NSR ready and a switchover should be hitless to the BGP control and data plane.




Explanation:


{master}[edit]user@router-RE0# run show task replicationStateful Replication: EnabledRE mode. MasterProtocol Synchronization StatusOSPF CompleteRIP CompleteBGP CompleteMPLS CompleteLDP Complete

{master}[edit]user@router-RE0# run show bgp summary | find 192.168.1.1192.168.1.1 65056 0 0 11:14 Establinet.0: 0/0/0/0inet.2: 0/0/0/0bgp.l3vpn.0: 0/0/0/0...

{backup}[edit]user@router-RE1# run show system switchoverGraceful switchover: OnConfiguration database. ReadyKernel database. SynchronizingPeer state. Steady State

{backup}[edit]user@router-RE1# run show bgp summary | find 192.168.1.1192.168.1.1 65056 306 581 0 7 7 Idle


You have been asked to determine if an NSR switchover will be hitless for a given BGP peer.

Referring to the exhibit, which statement is true?

A. The BGP session is idle on the backup RE indicating that the session will flap at switchover.


B. The task replication process has completed on the master indicating a hitless switchover can be expected.C. The GRES synchronization process is underway and must complete before the protocol state can be checked.D. The BGP session is idle on the backup RE which is normal; it toggles to established at mastership change.




[edit]user@router> show bgp summary...Peer AS InPkt OutPkt OutQ Flaps Last Up/Dwn State...5.1.1.1 100 10 0 1 14:06 Established10.1.1.1 200 10 0 1 14:06 Active20.1.1.1 300 10 0 1 14:06 Idle


Referring to the BGP peering sessions shown in the exhibit, which two statements are true? (Choose two.)

A. The peering session with the 10.1.1.1 neighbor is fully operational.B. The peering session with the 5.1.1.1 neighbor is fully operational.C. The local router peering with the 20.1.1.1 neighbor is waiting for a start event.D. The local router peering with the 20.1.1.1 neighbor is waiting for a BGP refresh message.





user@router> show bgp summaryGroups: 2 Peers: 2 Down peers: 2Table Tot Paths Act Paths Suppressed History Damp State Pendinginet.00 0 0 0 0 0Peer AS InPkt OutPkt OutQ Flaps Last Up/Dwn State...5.1.1.1 100 1 0 0 14:06 OpenConfirm10.1.1.1 200 0 1 14:06 Active


Two newly configured BGP peers have remained in the states shown in the exhibit for several hours.


A. The TCP three-way handshake has completed successfully with the 10.1.1.1 peer.B. The TCP three-way handshake has completed successfully with the 5.1.1.1 peer.C. The local router has received a BGP keepalive message from the 5.1.1.1 peer.D. The local router is initiating a transport protocol connection with the 10.1.1.1 peer.

Correct Answer: BDSection: BGPExplanation



user@router# run show route advertising-protocol bgp 192.168.12.1

user@router# run show routeinet.0: 11 destinations, 12 routes (11 active, 0 holddown, 0 hidden)+ = Active Route, - = Last Active, * = Both2.2.2.2/32 *[Direct/0] 3w6d 03:57:51> via lo0.0192.168.12.0/24 *[Direct/0] 01:07:34> via xe-0/0/0.0192.168.12.2/32 *[Local/0] 01:07:34


Local via xe-0/0/0.0200.1.0.0/16 *[Aggregate/130] 00:00:58Reject[IS-IS/165] 00:10:57, metric 10> to 200.1.1.2 via xe-0/0/3.0200.1.1.0/24 *[Direct/0] 00:29:21> via xe-0/0/3.0200.1.1.1/32 *[Local/0] 00:29:21Local via xe-0/0/3.0iso.0: 1 destinations, 1 routes (1 active, 0 holddown, 0 hidden)+ = Active Route, - = Last Active, * = Both49.0000.0020.0200.2002/72*[Direct/0] 3w4d 21:07:32> via lo0.0inet6.0: 3 destinations, 4 routes (3 active, 0 holddown, 0 hidden)+ = Active Route, - = Last Active, * = Both2:2:2::2/128 *[Direct/0] 3w4d 21:22:24> via lo0.0

[edit]user@router# show policy-optionspolicy-statement adv-route {term t1 {from {protocol isis;route-filter 200.1.0.0/16 exact;}then accept;}term t2 {then reject;}}

[edit]user@router# show protocols bgpgroup ebgp {type external;export adv-route;neighbor 192.168.12.1 {peer-as 65000;}}



Referring to the exhibit, why is the 200.1.0.0/16 prefix failing to be advertised in BGP?

A. BGP needs a next-hop self policy.B. The aggregate route is set to reject.C. The policy works for internal BGP only.D. The IS-IS route is less preferred than the aggregate route.






You are asked to configure a new external BGP peering. You have configured BGP on R1 as shown in the exhibit, however the BGP peering remains in Activestate.

Which additional configuration is required on R1 to establish the BGP peering?

A. Configure the local-address.B. Configure the BGP type as external.C. Remove the local-as statement.D. Remove the autonomous-system statement.




user@R1> show route protocol bgpinet.0: 6 destinations, 6 routes (6 active, 0 holddown, 0 hidden)+ = Active Route, - = Last Active, * = Both200.200.0.0/24 *[BGP/170] 00:00:47, localpref 100AS path: 65001 I> to 192.168.100.1 via ge-1/1/5.435200.200.1.0/24 *[BGP/170] 00:00:47, localpref 100AS path: 65001 I> to 192.168.100.1 via ge-1/1/5.435200.200.2.0/24 *[BGP/170] 00:00:47, localpref 100AS path: 65001 I> to 192.168.100.1 via ge-1/1/5.435200.200.3.0/24 *[BGP/170] 00:00:47, localpref 100AS path: 65001 I> to 192.168.100.1 via ge-1/1/5.435

user@R2> show route 200.200/16inet.0: 36 destinations, 36 routes (36 active, 0 holddown, 0 hidden)Restart Complete


+ = Active Route, - = Last Active, * = Both200.200.0.0/24 *[Static/5] 00:09:12Reject200.200.1.0/24 *[Static/5] 00:09:12Reject200.200.2.0/24 *[Static/5] 00:09:12Reject200.200.3.0/24 *[Static/5] 00:09:12Reject200.200.4.0/24 *[Static/5] 00:09:12Reject

user@R2> show configuration protocols bgpexport export-200;group c5 {neighbor 192.168.100.2 {export export-200.200;peer-as 65002;}}

user@R2> show configuration policy-options policy-statement export-200.200

term 1 {from {route-filter 200.200.0.0/22 longer;}then accept;}

user@R2> show configuration policy-options policy-statement export-200term 1 {from {route-filter 200.200.0.0/21 longer;}then accept;}


R2 is exporting static routes to R1 using BGP. R1 is not receiving one of the five static routes that is configured on R2.

Referring to the exhibit, what should be changed under the BGP configuration to resolve this issue?


A. Delete the global export policy.B. Delete the neighbor export policy.C. Move policy export-200 to the group level.D. Move policy export-200.200 to the group level.




user@router> show configuration interfaces ge-1/0/0unit 0 {family inet {address 192.168.100.1/30;}}

user@router> show configuration routing-optionsautonomous-system 65001;

user@router> show configuration protocols bgpgroup 65002 {traceoptions {file bgp-trace;flag open detail;}neighbor 192.168.100.3 {peer-as 65002;}}

user@router> show log bgp-traceFeb 5 20:31:01 R4 clear-log[5510]: logfile clearedFeb 5 20:32:22.658155 bgp_connect_complete. error connecting to 192.168.100.3 (External AS 65002): Socket is not connected


user@router> run monitor traffic interface ge-1/0/0 extensiveAddress resolution is ON. Use to avoid any reverse lookup delay.Address resolution timeout is 4s.Listening on ge-1/0/0, capture size 1514 bytes20:45:44.212833 OutJuniper PCAP Flags [Ext], PCAP Extension(s) total length 22Device Media Type Extension TLV #3, length 1, valuE. Ethernet (1)Logical Interface Encapsulation Extension TLV #6, length 1, valuE. Ethernet (14)Device Interface Index Extension TLV #1, length 2, valuE. 35328Logical Interface Index Extension TLV #4, length 4, valuE. 70Logical Unit Number Extension TLV #5, length 4, valuE. 32767

-----original packet-----

80:71:1f:c7:f8:60 > 84:18:88:8e:3b:3f, ethertype 802.1Q (0x8100), length 82: vlan 435, p 6, ethertype IPv4, (tos 0xc0, ttl 255, id 19548, offset 0, flags [DF], proto:TCP (6), length: 64) 192.168.100.1.bgp > 192.168.100.2.49373: S 1088527795:1088527795(0) ack 214564428 win 1638420:45:44.213226 InJuniper PCAP Flags [Ext, no-L2, In], PCAP Extension(s) total length 22Device Media Type Extension TLV #3, length 1, valuE. Ethernet (1)Logical Interface Encapsulation Extension TLV #6, length 1, valuE. Ethernet (14)Device Interface Index Extension TLV #1, length 2, valuE. 35328Logical Interface Index Extension TLV #4, length 4, valuE. 70Logical Unit Number Extension TLV #5, length 4, valuE. 32767

-----original packet-----

PFE proto 2 (ipv4): (tos 0xc0, ttl 1, id 2367, offset 0, flags [none], proto: TCP (6), length: 52) 192.168.100.2.49373 > 192.168.100.1.bgp: . 1:1(0) ack 1 win 17376


You are asked to configure an EBGP peering to AS 65002. The EBGP peering is stuck in a Connect state.

Referring to the exhibit, what should be changed to the BGP configuration to bring up the peering?

A. Configure the neighbor to 192.168.100.2.B. Configure the local-as to 65001.C. Configure the peer-as to 65001.D. Configure the peering as passive.





user@router> show configuration routing-optionsautonomous-system 65001;

user@router> show configuration protocols bgpgroup 65002 { traceoptions { file bgp-trace; flag open detail; } neighbor 192.168.100.2 { peer-as 65002; }}

user@router> show log bgp-traceFeb 5 20:07:08 trace_on: Tracing to "/var/log/bgp-trace" startedFeb 5 20:08:23.477912 bgp_senD. sending 63 bytes to 192.168.100.2 (External AS 65002)Feb 5 20:08:23.478040Feb 5 20:08:23.478040 BGP SEND 192.168.100.1+62776 -> 192.168.100.2+179Feb 5 20:08:23.478077 BGP SEND message type 1 (Open) length 63Feb 5 20:08:23.478100 BGP SEND version 4 as 65001 holdtime 90 id 10.200.1.4 parmlen 34Feb 5 20:08:23.478119 BGP SEND MP capability AFI=1, SAFI=1Feb 5 20:08:23.478138 BGP SEND Refresh capability, code=128Feb 5 20:08:23.478155 BGP SEND Refresh capability, code=2Feb 5 20:08:23.478176 BGP SEND Restart capability, code=64, time=120, flags=Feb 5 20:08:23.478196 BGP SEND Restart capability AFI=1, SAF=1, Flags=ForwardingSavedFeb 5 20:08:23.478217 BGP SEND 4 Byte AS-Path capability (65), as_num 65001Feb 5 20:08:23.478820Feb 5 20:08:23.478820 BGP RECV 192.168.100.2+179 -> 192.168.100.1+62776Feb 5 20:08:23.478859 BGP RECV message type 1 (Open) length 59Feb 5 20:08:23.478880 BGP RECV version 4 as 65003 holdtime 90 id 192.168.1.1 parmlen 30Feb 5 20:08:23.478899 BGP RECV MP capability AFI=1, SAFI=1Feb 5 20:08:23.478918 BGP RECV Refresh capability, code=128Feb 5 20:08:23.478935 BGP RECV Refresh capability, code=2Feb 5 20:08:23.478955 BGP RECV Restart capability, code=64, time=120, flags=


Feb 5 20:08:23.478974 BGP RECV 4 Byte AS-Path capability (65), as_num 65003Feb 5 20:08:23.479057 bgp_process_open: : NOTIFICATION sent to 192.168.100.2 (External AS 65002): code 2 (Open Message Error) subcode 2 (bad peer ASnumber), Reason: peer 192.168.100.2 (External AS 65002) claims 65003, 65002 configuredFeb 5 20:08:23.479083 bgp_send. sending 21 bytes to 192.168.100.2 (External AS 65002)Feb 5 20:08:23.479104Feb 5 20:08:23.479104 BGP SEND 192.168.100.1+62776 -> 192.168.100.2+179Feb 5 20:08:23.479136 BGP SEND message type 3 (Notification) length 21Feb 5 20:08:23.479156 BGP SEND Notification code 2 (Open Message Error) subcode 2 (bad peer AS number)


You have been asked to configure an EBGP peering to AS 65002. The EBGP peering is stuck in an Active state.

Referring to the exhibit, what would be changed to bring up the peering?

A. Configure the local-as to 65003.B. Configure the autonomous-system to 65003.C. Configure the EBGP peering as passive.D. Configure the peer-as to 65003.




[edit]user@router# show protocols bgpgroup ibgp { type internal; local-address 3.3.3.3; family inet; neighbor 2.2.2.2;}

[edit]


user@router# show routing-instances

VRF { instance-type vrf; interface xe-0/0/1.0; route-distinguisher 3.3.3.3:100; vrf-target target:100:100; vrf-table-label;}

[edit]user@router# show protocols mplsinterface all;

[edit]user@router# show protocols rsvpinterface all;


Referring to the exhibit, what is missing in the configuration to make the Layer 3 VPN functional? (Choose two.)

A. a label-switched pathB. the LDP protocol configurationC. a virtual circuit IDD. an NLRI of family inet-vpn unicast

Correct Answer: ADSection: BGPExplanation


QUESTION 22Which role does the router ID (RID) have in the BGP route selection process?

A. The router ID is evaluated immediately after MED to determine route preferenceB. The router ID is evaluated last in the route selection processC. The router ID is evaluated after the cluster length and a lower router ID is chosen


D. The router ID is evaluated after analyzing the IGP metric cost


Explanation/Reference:Reference:

http://www.juniper.net/techpubs/en_US/junos10.0/information-products/topic-collections/nog- baseline/bgp-routes-and-selection-introduction.html

QUESTION 23Which BGP state denotes a fully operational session?

A. EstablishedB. ActiveC. OperationalD. Connect



A fully operational BGP session is in the Established state.

Other BGP states include:- Active: BGP is initiating a transport protocol connection in an attempt to connect to a peer. If the connection is successful, BGP sends an Open message.- Connect: BGP is waiting for the transport protocol connection to complete- Established: The BGP session has been established, and the peers are exchanging update messages.- Idle: Either the BGP license check failed, or this is the first stage of a connection and BGP is waiting for a start event.- OpenConfirm: BGP has acknowledge receipt of an open message from the peer and is waiting to receive a keepalive or notification message.- OpenSent: BGP has sent an open message and is waiting to receive an open message form the peer



You work for the regional Internet service provider shown in the exhibit You have a partial BGP table and are receiving a 10 100/16 route from your upstream ISPYou have been asked to configure a default route that can be sent to your downstream customer This route should forward customer traffic toward your upstreamTier 11SP as long as the 10.100/16 route is present.

What would accomplish this goal?

A. Create and announce an aggregate default routeB. Create and announce a static default route with a next-hop of discardC. Create and announce a static default route with a next-hop of rejectD. Create and announce a generated default routeE. Create an advertise-map with exist-map

Correct Answer: ESection: BGPExplanation

Explanation/Reference:Reference:

http://www.juniper.fr/techpubs/en_US/junose10.0/information-products/topic-collections/swconfig- bgp-mpls/advertising-a-default-route-only-when-another-route-is-present.html

QUESTION 25Using industry best practices, what is true regarding an external BGP session?

A. BGP neighbors belong to the same ASB. BGP neighbors belong to a different ASC. BGP sessions rely on a static route for reach abilityD. BGP sessions will be established between loopback interface addresses.




QUESTION 26Which two BGP attributes are modified by default when they are passed between external BGP peers? (Choose two)

A. MEDB. AS-PathC. CommunitiesD. Next Hop



As-path and next-hop values are modified by default when they are passed between external BGP peers. BGP attributes are included in the update messages anddescribe the BGP prefixes received from a peer.

QUESTION 27Which two statements about BGP are accurate? (Choose two.)

A. BGP uses UDP port 500 for connectivity.B. BGP uses TCP port 179 for connectivity.C. External peering sessions require an underlying IGP.D. Internal peering sessions require an underlying IGP.




BGP uses TCP as its transport protocol, using port 179. Because IBGP connections often exist between non-adjacent devices, an IGP must be used to providereachability.

QUESTION 28Using industry best practices, which two BGP attributes would you modify to influence how traffic enters your network? (Choose two)

A. AS PathB. Local PreferenceC. Next HopD. MED



Based on industry best practices, you can use the BGP attributes AS-path and MED to influence how traffic enters your network. The AS-path attribute ismandatory; thus, it must always be present for all BGP routes.

QUESTION 29In which two environments would BGP add value? (Choose two)

A. an enterprise environment with a single upstream connectionB. an enterprise environment with multiple upstream connectionsC. a service provider environmentD. a home office environment



Normally, a single-homed network uses addresses assigned by the provider from the provider's aggregate, while the customer typically creates a default staticroute toward its provider. This is the simplest method to obtain Internet connectivity and does not have the complexity of BGP. When an enterprise has multihomedconnections to one or more multiple ISPs, they can use BGP path attributes to control inbound and outbound traffic. Because providers are used primarily for transit


to Internet locations, they employ BGP and its attributes to control traffic.


[edit protocols bgp]user@Router-X# showimport policy-a;export policy-b;group external { export policy-c; peer-as 4; neighbor 172.18.7.7; neighbor 172.18.4.5; import policy-d; } neighbor 172.16.1.3;}

Referring to the exhibit, which policy(s) will be applied to neighbor 172.18.4.5?


A. Import policy-a and policy-d, export policy-b and policy-cB. Import policy-d, export policy-b and policy-cC. Import policy-d, export policy-c.D. Import policy-d only



Based on the scenario, "import policy-d, export policy-c", is correct. You can apply import and export policies to BGP sessions at the neighbor, group, or protocollevel of the configuration hierarchy. However, a Junos device applies only the most specific import or export policy. Import or export polices applied at higher levelsof the configuration hierarchy will be inherited at lower levels of the configuration if no policy is configured at that lower level. However, if a policy is configured at alower level, the device applies only that more specific policy.



In the exhibit Router A and Router B are operating on the LAN with Router B acting as the designated intermediate system (DIS).

When Router C and Router D are added to the LAN. Which statement is true?

A. Router C becomes the new DIS with no backup DIS.B. Router D becomes the new DIS with no backup DIS.C. Router C becomes the new DIS with Router B as the backup DIS.D. Router D becomes the new DIS with Router A as the backup DIS.



QUESTION 32You are logged into a Junos device and issue the command show route protocol bgp. You see that the device has received the route 10 0.4/24 from two differentIBGP peers. Local preference, MED, origin, and AS-path values are equal.

Which criterion is used to determine which path will be preferred?


A. cluster lengthB. router ID (RID)C. peer IDD. IGP cost



Based on the scenario, IGP cost will be used.

QUESTION 33Which action does the local router take after sending a Notification message to a remote peer?

A. It begins to send route update informationB. It tears down the TCP session and attempts to re-establish itC. It waits for the remote router to acknowledge that it is ready to receive routesD. It changes its local state to Established



After sending a notification message to a remote peer, the local device tears down the TCP session and attempts to reestablish it.

BGP uses notification messages to signal when something is wrong with the BGP session. A notification is sent when an unsupported option is sent in an openmessage and when a peer fails to send an update to keepalive message. When an error is detected, the BGP session is closed.



In the exhibit, all devices are sending routes to Router B

Which routes will be advertised from Router B to Router D?

A. BGP routes learned from Router A onlyB. BGP routes learned from Router E onlyC. BGP routes learned from Routers A and C onlyD. BGP routes learned from Routers A, C and E only



Router B will advertise BGP routes learned from Router A, C, and E

QUESTION 35Which three statements are true about BGP? (Choose three)

A. iBGP peering adds value in small networks with a single upstream connection


B. iBGP peering adds value in small networks with multiple upstream connectionsC. eBGP peering adds value in small networks with multiple upstream connectionsD. iBGP peering adds value in large enterprise environments with multiple upstream connectionsE. eBGP peering adds value in large enterprise environments with multiple upstream connections

Correct Answer: CDESection: BGPExplanation


QUESTION 36What are three valid BGP message types? (Choose three.)

A. RefreshB. HelloC. RouteD. KeepaliveE. Open

Correct Answer: ADESection: BGPExplanation


BGP message types include:- open- update- keepalive- notification- refresh

QUESTION 37Your Junos device receives two similar route advertisements from different BGP peers.

What would cause a route to be selected in this scenario?


A. having a lower MED valueB. having a lower local preferenceC. learning a route from a peer with a higher peer IDD. learning a route from a peer with a higher IGP metric



When a Junos device receives two similar route advertisements from different BGP peers, it will select the route will the lowest MED value. BGP route selectionproceeds in this manner:

Prefer the highest local-preference valuePrefer the shortest AS-path lengthPrefer the lowest origin valuePrefer the lowest MED valuePrefer routes learned from an EBGP peer over an IBGP peerPrefer best exit from ASFor EBGP-receive routes, prefer the current active route:otherwise, prefer routes from the peer with the lowest RIDPrefer paths with the shortest cluster lengthPrefer routes from the peer with the lowest peer ID

QUESTION 38Your customer complains that their Layer 3 VPN is not passing traffic from one site to another. You assigned that customer to VPN-A. Which command on the PErouter will confirm the presence of customer routes?

A. show route VPN-AB. show route VPN-A table bgp.l2vpn.0C. show route table inet.3 VPN-AD. show route table VPN-A.inet.0




Explanation:

QUESTION 39You notice that a route from internal BGP peer 192.168.1.1 is missing from the local route table. Which two commands would be used to help identify the source ofthe problem? (Choose two.)

A. show route bgpB. show route protocol bgp hiddenC. show route receive-protocol bgp 192.168.1.1D. show route advertising-protocol bgp 192.168.1.1



Based on the scenario, you would use the show route protocol bgp hidden command to display routes that are hidden because of an import policy. You would usethe show route receive-protocol bgp 192.168.1.1 command to determine whether the route was sent by the advertising peer.



In the exhibit, all routers are sending routes to Router B.

Which routes will be advertised from Router B to Router E?

A. BGP routes learned from Router A onlyB. BGP routes learned from Router D onlyC. BGP routes learned from Routers A and C onlyD. BGP routes learned from Routers A, C, and D only



Router B will advertise BGP routes learned from Routers A, C, and D.

QUESTION 41Which two events could cause the BGP Active state to appear? (Choose two.)

A. The local device does not have a route to the peer device.B. The local device failed to establish a TCP connection with the peer device.C. A firewall is stopping all UDP packets.D. The BGP configuration is incomplete.



In the Active state, BGP is trying to acquire a peer by initiating a transport protocol connection. If the transport protocol connection succeeds, the local systemsends an open message to its peer and transitions to the OpenSent state. If the local system's BGP state remains in the Active state, you should check physicalconnectivity as well as the configuration of both peers.

QUESTION 42By default, which BGP attribute is only compared when two route advertisements are received from the same neighboring AS?


A. MEDB. AS-PathC. CommunitiesD. Next Hop



By default, BGP uses the multiple exit discriminator (MED) value only when the local AS has two or more connections to the same upstream AS.

QUESTION 43What are two uses of the AS-path attribute? (Choose two.)

A. It is used in BGP route selection.B. It is used to ensure that a packet traverses the least number of routers.C. It is used by IGPs to avoid loops within an autonomous system.D. It is used to avoid routing loops between autonomous systems.



The AS-path attribute is used as part of the BGP route selection process. It is also used to avoid routing loops between autonomous systems.

The AS-path attribute describes the path of autonomous systems that a prefix has passed through since it was sourced into BGP. By deafult, the AS-path lengthexpands as a prefix is shared between autonomous systems.

QUESTION 44How are BGP routes grouped when being sent in an update message?

A. by grouping aggregated address ranges togetherB. by using a complete set of matching attributes


C. by the originating autonomous systemD. by the originating router



When BGP routes are sent in an update message they are grouped by using a complete set of matching attributes. BGP uses update messages to transportrouting information between BGP peers. Depending on receiving device's routing polciy, this routing information is either added to the routing table or ignored.

QUESTION 45How are BGP routes originated?

A. BGP routes are created using policies associated with BGP peering sessions.B. BGP routes are created using IP subnet definitions at each defined BGP peer.C. BGP routes are created based on interface subnets used for peering sessions.D. BGP routes are created based on all interface subnets on all BGP routers.



QUESTION 46Which three statements are true about BGP default operations? (Choose three.)

A. IBGP peers advertise routes received from EBGP peers to other IBGP peers.B. IBGP peers do not advertise routes received from IBGP peers to other IBGP peers.C. IBGP peers do not advertise routes received from EBGP peers to other IBGP peers.D. IBGP peers change the next hop for routes received from EBGP peers.E. EBGP peers advertise routes learned from IBGP or EBGP peers to other EBGP peers.

Correct Answer: ABESection: BGP


Explanation




Which two statements are correct according to the output shown in the exhibit? (Choose two.)

A. The peering session is enabled for graceful restart.


B. The peering session uses the default route preference.C. The peering session is in a state in which routes can be exchanged.D. The peering session uses a 4-byte AS number.





Which two statements are correct according to the output shown in the exhibit? (Choose two.)

A. The peering session can pass inet-vpn routes.


B. The peering session uses an altered route preference.C. The peering session is enabled for multihop support.D. The peering session is enabled for multipath support.




[edit protocols bgp]user@host# showexport my-statics;group my-group { type external; export my-aggregates; neighbor 176.241.12.4 { peer-as 396; } neighbor 75.217.12.10 { export my-specifics; peer-as 3275; }}

Referring to the exhibit, which policy would be applied to the 75.217.12.10 neighbor?

A. The my-statics policy would be applied.B. The my-aggregates policy would be applied.C. The my-specifics policy would be applied.D. The my-statics, my-aggregates, and my-specifics policies would be applied.





In the exhibit, R1, R2, and R3 are all IBGP peers within AS 65505. R1 receives a BGP advertisement from an external BGP peer in AS 65555, and BGPadvertisement from R3. The default BGP advertisement behavior is in effect in this environment.

In this scenario, which two statements are true? (Choose two.)

A. R1 will advertise the route received from R3 to R2 and its external BGP peer.B. R1 will advertise the route received from R3 only to its external BGP peer.C. R1 will advertise the route received from its external peer to R2 and R3.D. R1 will not advertise the route received from its external peer to R2 or R3.



QUESTION 51Which two BGP attributes are mandatory? (Choose two.)

A. next hopB. aggregatorC. AS pathD. community

Correct Answer: ACSection: BGP


Explanation


QUESTION 52Which two elements are valid in the BGP path selection algorithm? (Choose two.)

A. lowest local preference valueB. lowest multi-exit discriminatorC. highest multi-exit discriminatorD. highest local preference value





Referring to the exhibit, MED is being used in your BGP network. All other BGP configurations use the default settings.

Which statement is correct regarding traffic destined to the 151.213.0.0/16 prefix in AS 358?

A. A traffic black hole will be created at Router A and Router B.B. Traffic will load-balance across both the A-to-C and B-to-D paths.C. Traffic will prefer the A-to-C path.D. Traffic will prefer the B-to-D path.



QUESTION 54



In the exhibit, R1 is sending the 172.16.100.0/24 route to R2 through EBGP. R2 has IBGP sessions to R3 and R4, but they are not installing the route. All BGPsessions are established.

A. Advertise the R1-R2 link into the IGP.B. Configure the cluster-id parameter under the R2 IBGP group.C. Configure a BGP export policy with a next-hop self action on R2.


D. Configure an IGP export policy with a next-hop self action on R2.

Correct Answer: ACSection: BGPExplanation


QUESTION 55You are logged in to an MX80 and issue the command "show route protocol bgp" You see that you have received the route 10.0.4/24 from two different peers. Onepeer is an external peer and the other is an internal peer. The route received from the internal peer is active.

By the rules of BGP preference, what would cause the internal path for this prefix to be preferred over the external one?

A. Internally learned prefix is preferred over an externally learned prefixB. The local-preference value of the internally learned prefix is higher than the externally learned peerC. The peer ID of the internally learned prefix is lower than that of the externally learned peerD. The internally learned prefix has a shorted cluster length



Based on the scenario, the prefix from the internal peer would be preferred if it has a higher local-preference value than the default value.

QUESTION 56Which two statements are true about the BGP MED attribute? (Choose two.)

A. It has a default value of 100B. It has an assumed value of 0C. It is designed for use when multiple connections exist between the same two autonomous systemsD. It is designed for use when a BGP router is peering with at least two different autonomous systems




MED is used to help influence the preferred path back into the autonomous system when multiple links exist between the same two autonomous systems. BGProutes do not require the MED attribute. If it is missing, BGP assumes the MED value is 0.

QUESTION 57What are three BGP attributes used in the route-selection process? (Choose three.)

A. local preferenceB. communitiesC. MEDD. originE. atomic aggregate

Correct Answer: ACDSection: BGPExplanation


- local preference- MED- Origin

QUESTION 58Which two commands would you use to see the export policy that has been applied to a BGP neighbor? (choose two.)

A. show bgp neighborB. show bgp summaryC. show bgp groupD. show bgp policy

Correct Answer: ACSection: BGPExplanation



Explanation:

The "show bgp neighbor" and "show bgp group" commands display polices applied at the neighbor and group levels

QUESTION 59Which method can be used to reduce the size of the upstream BGP routing table?

A. confederationsB. prefix aggregationC. atomic aggregateD. route reflection



Prefix aggregation is a method that can be used to reduce the size of upstream BGP routing tables. This method is commonly used in ISP deployments of BGP.

QUESTION 60Once the initial route exchange has been completed, how frequently does BGP automatically sent route updates?

A. every hourB. when the configured timer expiresC. whenever a routing policy is updatedD. as needed





Once the initial route exchange has been completed BGP automatically sends route updates as needed. BGP uses TCP to provide reliable communication, whichensures that BGP neighbors never miss an update. A system of keepalives also allows each BGP peer to ensure that its neighbors are still function properly. If aneighbor goes down, the BGP speaker deletes all routes learned from that peer and updates its other peers accordingly.


In the exhibit, all devices are sending routes to Router B.

Which routes will be advertised from Router B to Router C?

A. BGP routes learned from Router A onlyB. BGP routes learned from Router E onlyC. BGP routes learned from Routers D and E onlyD. BGP routes learned from Routers A, D, and E




Explanation:

Router B will advertise BGP routes learned from Routers D and E to Routers A and C (EBGP to IBGP). A BGP router never readvertises IBGP learned routes toother IBGP peers.

QUESTION 62Which three statements area true regarding BGP local preference? (Choose three.)

A. A higher value is preferred over a lower valueB. A lower value is preferred over a higher valueC. Local preference is not shared between autonomous systemsD. Local preference can be altered by policy or configurationE. Local preference has a default value of 128

Correct Answer: ACDSection: BGPExplanation


A higher local preference value is preferred over a lower value. These values are not shared between autonomous systems, and can be altered by policy orconfiguration. you can use the local preference attribute to direct outbound traffic through a specific peer.

QUESTION 63Using industry best practices, which BGP attribute would you modify to influence how traffic leaves your network?

A. MEDB. local preferenceC. AS-pathD. communities



The BGP local-preference attribute can be used to influence how traffic leaves your network. BGP uses the local-preference attribute only within an AS. Local


preference values are not transmitted across EBGP links.

QUESTION 64What are the differences between EBGP and IBGP?

A. EBGP peering requires a full mesh because EBGP speakers cannot readvertise EBGP-learned routesB. IBGP peering requires a full mesh because IBGP speakers cannot readvertise IBGP-learned routesC. Both EBGP and IBGP require a full mesh because BGP speakers cannot readvertise BGP-learned routesD. EBGP speakers can use route reflectors or confederations to avoid the full-mesh requirement



IBGP peering generally requires a full mesh because IBGP speakers cannot readvertise IBGP-learned routes. IBGP sessions are usually established betweenloopback addresses, whereas EBGP sessions are usually established using the IP addresses of the physically connected interfaces.

QUESTION 65Which criterion is evaluated first when selecting a BGP route?

A. MEDB. originC. local preferenceD. AS-path



The highest local-preference value is the fist criterion used in selecting a BGP route. There are nine selection criteria that can be used when selecting BGP routepreference:

The highest local-preference valueThe shortest AS-path length


The lowest origin valueThe lowest MED valueRouters learned from an EBGP peer over an IBGP peerBest exit from ASFor EBGP-received routes, the current active route:otherwise, routes from the peer with the lowest RIDPaths with the shortest cluster lengthRoutes from the peer with the lowest peer ID


[edit protocols bgp]user@router# showgroup external { neighbor 10.0.21.2;}

The exhibit shows a partial configuration for an external BGP session.

What must be added to complete the configuration?

A. the type external statementB. the peer-as statementC. the multi-hop statementD. the next-hop-self statement



Based on the exhibit, you need to add the peer-as statement. Adding this statement is necessary to indicate that the peer's AS value is different from that of thelocal device.

QUESTION 67Which type of BGP message is used to perform a soft clearing of a BGP session?

A. refresh


B. updateC. notificationD. open



A refresh message is used to perform a soft clearing of a BGP session. Normally a BGP speaker cannot be made to readvertise routes that have already been sentand acknowledged. The route refresh message supports soft clearing of BGP sessions by allowing a peer to readvertise routes that have already been sent.


[edit protocols bgp]user@router# showgroup internal { neighbor 10.0.16.2;}

The exhibit shows a partial configuration fo an internal BGP session.

Which two statements must be added to complete the configuration (Choose two.)

A. a local-address statementB. a type ibgp statementC. a next-hop-self statementD. a type internal statement



Based on the scenario, you would need to add the local-address and type internal statements. A configuration error will occur if these statements are not added.



In the exhibit, all devices are sending routes to Router B.

Which routes will be advertised from Router B to Router A?

A. BGP routes learned from Router C onlyB. BGP routes leaned from Router E onlyC. BGP routes learned from Routers D and E onlyD. BGP routes learned from Routers C, D, and E



Router B will advertise BGP routes learned from Routers D and E only



-- Exhibit --

[edit]user@Router-X# show policy-options policy-statement nhs term 1 { from { protocol bgp; neighbor 10.0.21.2; } then next-hop self; }}

A Junos device has an external peering session to 10.0.21.2 and several internal peers.

How can the policy reference in the exhibit be used to ensure routes are usable?


A. Apply it as an import policy to internal BGP peersB. Apply it as an export policy to internal BGP peersC. Apply it as an import policy to external BGP peersD. Apply it as an export policy to external BGP peers



As a best practice, always apply a next-hop self policy as an export policy to internal peers or to the BGP group to wich those peers belong. Improper application ofa next-hop-self policy can cause suboptimal routing or result in hidden routes.


Layer 2 Switching VLAN's


-- Exhibit --


In the exhibit, A1 sends a broadcast frame with destination MAC address FFFF.FFFF.FFFF, and all other stations have sent a response .

What would be the correct MAC address table on the MX240?

ge-0/0/0 0140.5501.1111

A. ge-0/0/0 FFFF.FFFF.FFFFB. ge-0/0/0 FFFF.FFFF.FFFFC. ge-0/0/0 0140.5501.2222

ge-0/0/1 0140.5501.3333ge-0/0/1 0140.5501.4444ge-0/0/0 0140.5501.1111

D. ge-0/0/0 0140.5501.2222ge-0/0/1 0140.5501.3333ge-0/0/1 0140.5501.4444



Correct Answer: DSection: Layer 2 Switching VLAN'sExplanation



user@router# show interfacesxe-0/0/0 { unit 0 { family inet { address 192.168.12.1/24; } family mpls; }}xe-0/0/1 { encapsulation ethernet-ccc; unit 0 { family ccc; } }lo0 { unit 0 { family inet { address 1.1.1.1/32; } }}

[edit]user@router# show protocolsmpls { interface all; } ospf { traffic-engineering;


area 0.0.0.0 { interface all; }}ldp { interface all;}l2circuit { neighbor 2.2.2.2 { interface xe-0/0/1.0 { } }}

-- Exhibit --


In the exhibit, which configuration element is missing to bring up the Layer 2 circuit?

A. the route targetB. the virtual circuit IDC. a targeted LDP sessionD. an MPLS LSP

Correct Answer: BSection: Layer 2 Switching VLAN'sExplanation


QUESTION 3What are two valid actions that can be applied to a frame by a Layer 2 firewall filter? (Choose two)

A. LogB. loss-priorityC. sampleD. count


Correct Answer: BDSection: Layer 2 Switching VLAN'sExplanation

Explanation/Reference:Explanation: The correct answers are B, D.Reference:

You can specify the following filter actions:

* accept* count counter-name* discard* dscp code-point (family inet only)* forwarding-class class-name* ipsec-sa ipsec-sa (family inet only)* load-balance group-name (family inet only)* log (family inet and inet6 only)* logical-system logical-system-name (family inet and inet6 only)* loss-priority (high | medium-high | medium-low | low)* next term* next-hop-group group-name (family inet only)* policer policer-name* port-mirror (family bridge, ccc, inet, inet6, and vpls only)* prefix-action action-name (family inet only)* reject <message-type> (family inet and inet6 only)* routing-instance routing-instance-name (family inet and inet6 only)* sample (family inet, inet6, and mpls only)* service-accounting (service filters and family inet or inet6 only)* service-filter-hit (service filters and family inet or inet6 only)* syslog (family inet and inet6 only)* three-color-policer policer-name* topology topology-name (family inet and inet6 only)* traffic-class code-point (family inet6) only

QUESTION 4Which protocol is used by wired Ethernet to manage frame collisions?

A. IEEE 802.3 active monitoringB. IEEE 802.5 active monitoringC. carrier-sense multiple access with collision avoidance


D. carrier-sense multiple access with collision detection



In a shared Ethernet LAN, node transmissions are managed using a mechanism known as carrier-sense multiple access with collision detection, or CSMA/CD.

QUESTION 5A customer configures a bridge domain using a VLAN ID of 222.

Which configuration will allow for the switch to potentially look at the IP header of incoming frames tagged with a VLAN ID of 222?

A. [edit]user@switch# show bridge-domainsvlan-222 vlan-id 222; layer3-interface irb.0;}

B. [edit]user@switch# show bridge-domainsvlan-222 vlan-id 222; layer3-interface lt.0;}

C. [edit]user@switch# show bridge-domainsvlan-222 vlan-id 222; routing-interface lt.0;}

D. [edit]user@switch# show bridge-domainsvlan-222 vlan-id 222; routing-interface irb.0;}




QUESTION 6Which configuration can be applied to ensure that no more than 600 MAC addresses are learned by a virtual switch?

A. protocols { l2-learning { global-mac-limit { 600; } }}

B. switch-options { mac-table-size { 600; }}

C. bridge-domains { vlan_100 { vlan-id 100; bridge-options { mac-table-size { 600; } } }}

D. bridge-domains { bridge-options { mac-table-size { 600; } } vlan_100 { vlan-id 100; }


}



To limit the number of MAC addresses that can be learned by a switch at a global level, use the global-mac-limit statement under the [edit protocols l2-learning]hierarchy. To limit at the virtual switch level, use the mac-table-size statement under the [edit switch-options] hierarchy.

QUESTION 7Which two problems occur when increasing numbers of users are added to an Ethernet LAN with no switches present? (Choose two.)

A. There is a greater chance for collisions to occurB. The MAC table sizes increaseC. Some devices will not see certain trafficD. There is unnecessary consumption of network bandwidth "Pass Any Exam. Any Time." - www.actualtests.com 108 Juniper JN0-360 Exam

Correct Answer: ADSection: Layer 2 Switching VLAN'sExplanation



firewall { family bridge { filter filterA { term 10 { then count countA; } } filter filterB term 10 then count countB }


}interfaces ge-1/0/3 { unit 0 { family bridge { filter { input filterA; } interface-mode trunk; vlan-id-list 121; } } }}bridge-domains { customer { vlan-id 121; forwarding-options { filter { input filterB; } } }}

Which firewall filter action(s) will be applied to incoming frames to ge-1/0/3?

A. Frames will be counted initially by filterB and then counted by filterA.B. Frames will be counted initially by filterA and then counted by filterB.C. Frames will be counted by filterA only.D. Frames will be counted by filterB only.





[edit]user@switch# show bridge-domainsvlan_100 { vlan-id 100; interface ge-1/0/3.100;}vlan_200 { vlan-id 200; interface ge-1/0/3.200;}

Two bridge domains are configured as shown in the exhibit.

What must be configured as part of the ge-1/0/3 interface configuration to accept tagged frames of VLANs 100 and 200?

A. encapsulation vlan-bridgeB. encapsulation ethernet-bridgeC. interface-mode trunkD. vlan-id-range [100 200]

Correct Answer: CSection: Layer 2 Switching VLAN'sExplanation


QUESTION 10What are two characteristics of a traditional Ethernet LAN? (Choose two.)

A. Nodes share a physical medium.B. Nodes can successfully transmit simultaneously.C. It consists of a single broadcast domain.D. Nodes use a step-up algorithm when collisions are detected.

Correct Answer: ACSection: Layer 2 Switching VLAN'sExplanation



In a shared Ethernet LAN, all nodes are in the same broadcast domain and collision domain

QUESTION 11What is the size of the unique address used to identify each node on an Ethernet LAN?

A. 3 bytesB. 6 bytesC. 9 bytesD. 12 bytes



An Ethernet MAC address is 6 bytes, or 48 bits, long.


bridge-domains { bd { vlan-id 100; bridge-options { mac-table-size { 3000; } } }}

After the MAC learning limit of 3000 is reached for the bd bridge domain as shown in the exhibit, what happens to frames that arrive that contain unknown unicastdestination addresses?

A. They are flooded.B. The are forwarded to the default gateway.


C. They are dropped.D. They are forwarded to the IRB interface.

Correct Answer: ASection: Layer 2 Switching VLAN'sExplanation


The default behavior when the bridge table reaches the maximum number of MAC addresses is to flood all packets containing unknown destination MACaddresses. This default behavior can be changed by adding the packet-option drop statement to the existing configuration.

QUESTION 13An Ethernet bridge is configured such that all interfaces are in a single broadcast domain. Which two tasks does an Ethernet bridge perform in response toreceiving a frame with an unknown unicast destination MAC address? (Choose two.)

A. It drops the frame.B. It floods the frame out of all interfaces except the one on which is was received.C. It learns the destination MAC address when it sees return traffic from the device.D. It learns the source MAC address when it sees return traffic from that device.

Correct Answer: BCSection: Layer 2 Switching VLAN'sExplanation


When a bridge receives a data frame with an unknown destination MAC address, the frame is flooded out all other ports in the same broadcast domain. Once thebridge sess return traffic from this MAC address, it adds the address to the bridge table.

QUESTION 14You are configuring a trunk interface on an MX Series device and want to ensure that any outgoing frames associated with VLAN 100 are transmitted as untaggedframes.

Which configuration will achieve this objective?

A. routing-interface irb.0B. vlan-id-list [100]


C. native-vlan-id 100D. vlan-id 100




Referring to the exhibit, all interswitch links are configured as trunks supporting all VLANs. Host A sends a frame with an unknown destination MAC address to S2.

Which switches will receive this frame?

A. S1, S3 and S4B. S1 onlyC. S1 and S3 onlyD. S1 and S4 only



QUESTION 16Which Layer 2 mechanism logically groups network nodes into separate broadcast domains?


A. IS-IS levelsB. OSPF areasC. VLAND. IP subnets



QUESTION 17You have multiple Layer 2 interfaces associated with different VLANs configured on an MX Series router. You have been asked to ensure Layer 3 reachabilitythrough the MX Series router for the subnets associated with the different VLANs.

How would you meet this objective?

A. Use gateway IRB interfaces to forward traffic between VLANs.B. Use the BPDU protect feature to direct traffic between VLANs.C. Use a Layer 2 routing policy to forward traffic between VLANs.D. Use filter-based forwarding to direct traffic between VLANs.



QUESTION 18What are two valid statements for virtual switches on MX Series devices? (Choose two.)

A. Integrating routing and bridging (IRB) interfaces are supported.B. Layer 2 interfaces are supported.C. Interfaces are inherently loop free.D. Trunk interfaces are not supported.

Correct Answer: AB


Section: Layer 2 Switching VLAN'sExplanation


QUESTION 19Which two problems occur when increasing numbers of users are added to traditional hub-based Ethernet LAN? (Choose two.)

A. There is a greater chance for collisions to occurB. The MAC table sizes increaseC. Some devices will not see certain trafficD. There is unnecessary consumption of network bandwidth

Correct Answer: ADSection: Layer 2 Switching VLAN'sExplanation


As nodes are added to a shared Ethernet LAN, the likelihood of collisions increases, which in turn consumes more network bandwidth, adversely effectingperformance.

QUESTION 20On an MX Series device, which parameter is used to configure the timeout interval fo entries in the MAC table?

A. global-mac-table-aging-timeB. global-mac-limitC. switch-mac-table-aging-timeD. switch-mac-limit



Switches have an efficient method of managing stale MAC addresses, which is an aging timer. For MX Series devices, the aging timer defaults to a value of 300


seconds. This value can be changed using the global-mac-table-aging-time parameter under the [edit protocols l2-learning] hierarchy.

QUESTION 21Which bridging mechanism is used to ensure that only active entries are in the bridge table?

A. learning B. forwardingC. floodingD. filteringE. aging

Correct Answer: ESection: Layer 2 Switching VLAN'sExplanation


Aging is used to ensure that the bridge table remains current.

QUESTION 22What are two benefits of using MVRP? (Choose two.)

A. It reduces network administration and overheadB. It dynamically creates and prunes VLANsC. It provides redundancy for Layer 2 interfacesD. It dynamically translates Layer 2 addresses to Layer 3 addresses

Correct Answer: ABSection: Layer 2 Switching VLAN'sExplanation


The Multiple VLAN Registration Protocol (MVRP) simplifies VLAN management by dynamically managing VLAN registration in a LAN. MVRP helps reduceadministration and network overhead by dynamically pruning VLAN information when a switch no longer has active access ports, and by dynamically creating newlyconfigured VLANs.

QUESTION 23


By default, which two tasks does an Ethernet bridge perform in response to receiving a multicast frame? (Choose two.)

A. It learns the MAC address of any responding nodes and updates its bridge table with the source MAC address and ingress portB. It drops the frameC. It floods the frame out of all interfaces except the one on which it was receivedD. It floods the frame out of particular interfaces based on its multicast MAC table.



Multicast packets are flooded out all ports except for the port on which it was received. When an unknown destination responds to traffic that has been floodedthrough a switch, the switch learns the MAC address fo that node and updates its bridge table with the source MAC address and ingress port.

QUESTION 24Where would you configure MVRP in a multiswitch environment?

A. on all interfacesB. on access portsC. on trunk portsD. within the bridge domain



The implementation of MVRP, which is used to dynamically learn and delete VLANs, is configured at the [edit protocols mvrp] hierarchy level. Only trunk pointsshould be included; access ports are configured normally.

QUESTION 25Which command is used to display the Layer 2 forwarding table on an MX Series device?

A. show bridge-switching tableB. show ethernet-switching table


C. show bridge-mac tableD. show bridge table



On an MX Series device, the command to display the forwarding table is show bridge-mac table.

QUESTION 26What are three functions of a provider edge bridge when implementing provider bridging? (Choose three.)

A. to forward frames based only on the S-VLAN tagB. to encapsulate customer frames and append a C-VLAN tagC. to forward IEEE 802.1Q frames to customersD. to encapsulate customer frames using the IEEE 802.1ad formatE. to forward customer frames across a provider bridged network

Correct Answer: CDESection: Layer 2 Switching VLAN'sExplanation


A provider network can provide Layer 2 forwarding services for customers wishing to connect their remote sites together. The provider uses 802.1ad double-taggedframes across their network and delivers the 802.1Q frames to the customer network at the remote end.

QUESTION 27Which configuration correctly enables an IRB interface on an MX Series device?

A. [edit]user@switch# show bridge-domainsvlan-222 vlan-id 222; layer3-interface irb.0;}


B. [edit]user@switch# show bridge-domainsvlan-222 vlan-id 222; layer3-interface lt.0;}

C. [edit]user@switch# show bridge-domainsvlan-222 vlan-id 222; routing-interface lt.0;}

D. [edit]user@switch# show bridge-domainsvlan-222 vlan-id 222; routing-interface irb.0;}



The following configuration (show above in xml format) is the correct answer as it correctly includes the routing-interface irb

set bridge-domains vlan-222 vlan-id 222set bridge-domains vlan-222 routing-interface ibr.0

QUESTION 28As frames are processed by a switch, which statement is true about how the switch builds its MAC table?

A. The source addresses fo the frames are associated with the inbound interfaceB. The source addresses fo the frames are associated with the outbound interfaceC. The destination addresses fo the frames are associated with the inbound interfaceD. The destination addresses fo the frames are associated with the outbound interface

Correct Answer: ASection: Layer 2 Switching VLAN's


Explanation


The initial function a bridge performs when it receives a frame is to update the bridge table with the source MAC address and the port it came in on if the MACaddress was not previously known.

QUESTION 29What are two port modes for a Layer 2 interface? (Choose two.)

A. access modeB. dual modeC. trunk modeD. tag mod



Access ports typically connect to end systems such as PCs and printers, while trunk ports typically connect to other switches.

QUESTION 30Which command is used to configure an IRB interface?

A. set family inet interface irb unit 0 address 192.168.1.1/24B. set interface irb unit 0 family inet address 192.168.1.1/24

http://www.gratisexam.com/C. set interface unit 0 family irb address 192.168.1.1/24D. set bridge-domain 0 interface irb address 192.168.1.1/24

Correct Answer: BSection: Layer 2 Switching VLAN's


Explanation


An IRB interface is configured similar to a physical Layer 3 interface, by specifying an interface type irb, a logical unit, a protocol family, and an IP address (usingCIDR notation).


IPv6

QUESTION 1What are two valid IPv6 addresses? (Choose two.)

A. 2bfc::02:0:0:fec:5c

http://www.gratisexam.com/B. 2bfc::2::fec:5cC. 2bfc:2:0:0:fec:5cD. 2bfc:0:0:2::fe c:5c

Correct Answer: ADSection: IPv6Explanation


QUESTION 2Which new field is added to the IPv6 header when compared to IPv4?

A. versionB. fragment offsetC. checksumD. flow label

Correct Answer: DSection: IPv6Explanation


From the viewpoint of the network layer, a flow is a sequence of packets sent from a particular source to a particular unicast, anycast, or multicast destination that a node desires to label as a


flow. From an upper-layer viewpoint, a flow could consist of all packets in one direction of a specific transport connection or media stream. However, a flow is not necessarily 1:1 mapped to a transport connection.

Traditionally, flow classifiers have been based on the 5-tuple of the source address, destination address, source port, destination port, and the transport protocol type. However, some of these fields may be unavailable due to either fragmentation or encryption, or locating them past a chain of IPv6 extension headers may be inefficient. Additionally, if classifiers depend only on IP-layer headers, later introduction of alternative transport-layer protocols will be easier.

The usage of the 3-tuple of the Flow Label, Source Address, and Destination Address fields enables efficient IPv6 flow classification, where only IPv6 main header fields in fixed positions are used.

The flow label could be used in both stateless and stateful scenarios. A stateless scenario is one where any node that processes the flow label in any way does not need to store any information about a flow before or after a packet has been processed. A stateful scenario is one where a node that processes the flow label value needs to store information about the flow, including the flow label value.

https://tools.ietf.org/html/rfc6437

QUESTION 3Which three are valid IPv6 extension headers? (Choose three.)

A. multicast headerB. authentication headerC. autoconfiguration optionsD. fragmentE. hop-by-hop options

Correct Answer: BDESection: IPv6Explanation



QUESTION 4What are two components of an IPv6 router advertisement message? (Choose two.)

A. DHCPv6 requestB. Layer 2 address of advertising routerC. duplicate address detection notificationD. link MTU

Correct Answer: BDSection: IPv6Explanation


QUESTION 5Which two statements are correct about neighbor discovery in IPv6? (Choose two.)

A. Neighbor discovery relies on ARP to find neighbors on a local link.B. A neighbor is considered reachable when the neighboring device responds to a neighbor solicitation message.C. A neighbor is considered reachable when the neighboring device responds to a router solicitation message.D. Neighbor discovery does not use ARP to find neighbors on a local link.

Correct Answer: BDSection: IPv6Explanation


QUESTION 6You want to configure an interface on your router to use an IPv6 global IP address.

Which three methods accomplish this task? (Choose three.)

A. Use stateless autoconfiguration to assign only the 64 bit interface ID.B. Use stateful autoconfiguration to assign only the 64 bit interface ID.


C. Use stateful autoconfiguration to assign the entire global IPv6 address.D. Use a statically assigned global IPv6 address.E. Use stateless autoconfiguration to assign the entire global IPv6 address

Correct Answer: ACDSection: IPv6Explanation


QUESTION 7Which two statements describe differences between IPv4 and IPv6? (Choose two)

A. IPsec is built into IPv6B. IPv6 uses a 32-bit (4-byte) address and can support up to 4,294,967,296 addressesC. IPv4 supports extension headers whereas IPv6 options are integrated into the baseD. IPv6 eliminates the need for NAT



A few of the benefits fo IPv6 include more efficient routing, CoS, no need for NAT, stateless address autoconfiguration, reduced header size, and built-in NetworkLayer security using IPSec.

QUESTION 8You have been asked to configure an IPv6 address for a group of interfaces that could belong on different devices. If a packet is sent to that address, it should bereceived by all routers in the group.

Which address type would be suited for these requirements?

A. UnicastB. MulticastC. AnycastD. Broadcast


Correct Answer: BSection: IPv6Explanation


There are three types fo IPv6 address: unicast, multicast, and anycast.

A unicast address is a unique address that identifies an interface or node. A packet with a unicast address travels only to the interface identified.

A multicast address is an identifier for a group fo IPv6 interfaces that might belong to different nodes. An IPv6 packet with the multicast address as the destinationtravels to all interfaces in the group.

An anycast address is an identifier for a group of IPv6 interfaces that might belong to different nodes. However, unlink multicast addresses, an IPv6 packet with theanycast address as the destination travels to only one of the nodes identified in the group - typically the nearest node.

QUESTION 9What is the function of the hop limit field in the IPv6 header?

A. It limits the diameter of the network to 20 hopsB. It sets the number of hops in the network to be equal to the MPLS header time-to-live (TTL)C. It replaces the time-to-live (TTL) field in IPv4D. It represents future extensibility to the protocol

Correct Answer: CSection: IPv6Explanation


The 8-bit hop limit field replaces the time-to-live (TTL) field in an IPv4 header.

QUESTION 10You own a home network connecting through an always-on connection and need to assign IPv6 addresses to your routers because you want to follow theguidelines spelled out in RFC 3177. You want to design your network with the correct prefixes.

Which prefix would your ISP likely allocate to your network?


A. 47-bit prefixB. 48-bit prefixC. 64-bit prefixD. 128-bit prefix



From RFC 3177: This document provides recommendations to the addressing registries (APNIC, ARIN and RIPE-NCC) on policies for assigning IPv6 addressblocks to end sites. In particular, it recommends the assignment of /48 in the general case, /64 when it is known that one and only one subnet is needed and /128when it is absolutely known that one and only one device is connecting.

QUESTION 11You have been asked to configure and assign addresses for your IPv6 routers in your network using dynamic assignment of DNS servers. You do not want theMAC address included as part of the IPv6 address.

Which method of address assignment would accomplish these requirements?

A. DHCPB. stateless auto configurationC. DHCPv6D. stateful auto configuration



Stateless autoconfiguration uses the interfaces MAC address by default to generate the unique interface address. Standard DHCP supports only IPv4 addressing.DHCPv6 should be used to automatically assign IPv6 addresses based on scenarios requirements.

QUESTION 12You have just configured IPv6 in your network. A packet arrives on your router that exceeds the MTU size. How does the device respond?


A. The fragment offset is referenced and the packet is fragmented.B. The packet is kept intact and not fragmented.C. The packet is dropped.D. The packet is fragmented based on extension headers.



In IPv6 fragmentation must be handled by the source device. If a packet is received on an IPv6 interface that requires fragmentation because of the MTU, thepacket is dropped.

QUESTION 13You have been asked to use a convention that allows for auto configuration of interface addresses. You are not allowed to use DHCPv6. What do you do?

A. Use IPv4 with the autoconfig parameter under the family inet statement.B. Use IPv6 in the network to configure hosts.C. Use a program (e.g. Vector-Wiz) to auto configure IP addresses.D. Use an IPv6 static configuration.



One of the enhancements to IPv6 is the implementation of stateless autoconfiguration, which allows IPv6 nodes to effectively eliminate the need for static addressassignment and DHCP

QUESTION 14What are three ways to configure IPv6 addresses in your network? (Choose three.)

A. Statically configure your IPv6 addresses.B. Configure your IPv6 addresses using stateless auto configuration.C. Configure your IPv6 addresses by setting up a DHCPv6 server.


D. Configure your IPv6 addresses by assigning your router a prefix list.E. Configure your IPv6 addresses by configuring support for unicast-arp-negotiation.

Correct Answer: ABCSection: IPv6Explanation


QUESTION 15You own a small company and need to assign IPv6 addresses to your routers. Because you want to follow the guidelines spelled out in RFC 3177, you want todesign your network with the correct prefixes. Which prefix would your ISP likely allocate to your company?

A. 47-bit prefixB. 48-bit prefixC. 64-bit prefixD. 128-bit prefix



QUESTION 16Your network consists of multiple remote locations using both IPv4 and IPv6. You have an IPv4- based Internet connection at each site provided by different, localservice providers. You are asked to ensure that the remote IPv6 networks are able to communicate.

What should you do?

A. Create GRE tunnels between the remote locations to connect the IPv6 networks.B. Create IPsec tunnels between the remote locations to connect the IPv6 networks.C. Create IP-IP tunnels between the remote locations to connect the IPv6 networks.D. Create MPLS tunnels between the remote locations to connect the IPv6 networks.




QUESTION 17Which three IPv6 addresses are valid equivalents for the address 2001:0000:0000:0000:0134:fc0e:cc8b:458a? (Choose three?)

A. 2001:134:fc0e:cc8b:458aB. 2001:0:0:0:0134:fc0e:cc8b:458aC. 2001:0:0:0134:fc0e:cc8b:458aD. 2001::134:fc0e:cc8b:458aE. 2001:0::0:134:fc0e:cc8b:458a

Correct Answer: BDESection: IPv6Explanation



[edit]user@host# show protocols ospf3area 28.32.69.49 { interface all;}


Which statement is true regarding the output shown in the exhibit?

A. The configuration supports IPv4 multicast routes.B. The configuration supports IPv4 unicast routes.C. The configuration supports IPv6 unicast routes.D. The configuration supports IPv6 multicast routes.

Correct Answer: CSection: IPv6


Explanation


QUESTION 19What are two ways to assign an IPv6 to an interface? (Choose two.)

A. Use static addressing.B. Use neighbor discovery.C. Use an auto-configuration based on the interface MAC address.D. Use an IPv6 routing protocol.

Correct Answer: ACSection: IPv6Explanation


QUESTION 20What is the correct format for an IPv4 address mapped into IPv6?

A. ::192:168:0:1B. ::FFFF:192.168.0.1C. ::FFFE:192:168:0:1D. ::192.168.0.1:FFFF



QUESTION 21Which routing table is used to store known IPv6 routes?

A. inet0


B. inet.6C. inet6.0D. inet.2



IPv6 routes are stored in the inet6.0 routing table on Junos devices.

QUESTION 22What are three ways to configure IPv6 addresses in your network? (Choose three.)

A. static configurationB. stateless autoconfigurationC. using a DHCPv6 serverD. by assigning your device a prefix listE. by configuring support for unicast ARP negotiation

Correct Answer: ABCSection: IPv6Explanation


IPv6 addresses can be assigned to an interface in three methods. Similarly to IPv6, an address can be statically assigned. IPv6 addresses also can be assignedusing DHCPv6 server to assign the addresses dynamically. A third method, stateless autoconfiguration, is unique to IPv6 and facilitates automatic assignment ofIPv6 address to neighbor devices.

QUESTION 23An IPv6 address consists of how many bits?

A. 256B. 128C. 64


D. 32



IPv6 addresses are 128 bits long.

QUESTION 24You have been asked to configure your Junos device for IPv6. Your addressing must be unique and the packets can travel only to the interface defined in yourconfiguration.

Which address type would be suited for these requirements?

A. UnicastB. MulticastC. AnycastD. Broadcast

Correct Answer: ASection: IPv6Explanation


There are three types fo IPv6 address: unicast, multicast, and anycast.

A unicast address is a unique address that identifies an interface or node. A packet with a unicast address travels only to the interface identified.

A multicast address is an identifier for a group fo IPv6 interfaces that might belong to different nodes. An IPv6 packet with the multicast address as the destinationtravels to all interfaces in the group.

An anycast address is an identifier for a group of IPv6 interfaces that might belong to different nodes. However, unlink multicast addresses, an IPv6 packet with theanycast address as the destination travels to only one of the nodes identified in the group - typically the nearest node.

QUESTION 25Which two extension headers are supported in IPv6 (Choose two.)


A. fragment headerB. traffic class headerC. encapsulation headerD. authentication header



IPv6 uses six extension headers:- hop-by-hop options- routing- fragment- destination options- authentication- encrypted security payload

QUESTION 26You have been asked to configure the interfaces on your Junos device with the IPv6 addresses. You are aware that some IPv6 addresses are reserved. Based onRFC 4291, which IPv6 address is available for public use?

A. ::/128B. fe80::/10C. ff00::/8D. 2bfc::0/64



Just like the reserved IPv4 prefixes in RFC 1918, certain IPv6 prefixes are reserved and should be used only for specific types of traffic. RFC 4291 defines thelatest rules regarding these prefixes, which include ::/128, ::1/128, FF00::/8, FE80::/10.


QUESTION 27Which two statements are true regarding MAC address resolution for IPv6? (Choose two.)

A. IPv6 uses ARP to resolve the MAC address of a remote hostB. IPv6 MAC addresses are learned in router solicitation messagesC. IPv6 uses multicast packets to resolve the MAC addressD. To view the link-layer address of IPv6 neighbors, use the show ipv6 neighbors command

Correct Answer: CDSection: IPv6Explanation


IPv4 uses ARP to resolve Layer 2 addresses; however, ARP relies on the use of broadcast packets. IPv6 does not have the concept of broadcasts. Therefore, IPv6uses the solicited-node multicast method to resolve Layer 2 addresses. IPv6 uses five types of ICMP messages to perform neighbor discovery functions, includingrouter advertisement, router solicitation, neighbor solicitation, neighbor advertisement, and redirects. You can use the show ipv6 neighbors command to reviewinformation about known IPv6 neighbors.

QUESTION 28Which multicast address is used for sending neighbor solicitation messages?

A. solicited-node multicastB. all-nodes multicastC. solicited-router multicastD. all-routers multicast

Correct Answer: ASection: IPv6Explanation


Neighbor discovery uses three common multicast addresses for sending messages to neighbors:

- Neighbor solicitation messages use the solicited -node multicast address.- Router advertisements use the all-nodes multicast address.- Router solicitation messages use the all-routers multicast address.


QUESTION 29Which multicast address is used for sending router solicitation messages?

A. solicited-node multicastB. all-nodes multicastC. solicited-router multicastD. all-routers multicast



Neighbor discovery uses three common multicast addresses for sending messages to neighbors:

- Neighbor solicitation messages use the solicited -node multicast address.- Router advertisements use the all-nodes multicast address.- Router solicitation messages use the all-routers multicast address.

QUESTION 30You are analyzing traffic on an IPv6-speaking device and notice periodic and regular ARP and ICMP transmissions.

Why might these transmissions be occurring?


A. A device in the network is suffering from a broadcast storm attackB. A device in the network has been configured to automatically assign IPv6 addresses to downstream devicesC. Neighbor discovery is configured on your device and ICMP is being used to determine whether a neighbor is reachableD. DHCPv6 has been configured on a downstream device and it is requesting an address assignment




Neighbor discovery (ND) uses ICMP messages to detect whether neighbors are reachable. A device views a neighbor as reachable when the device receivesrecent confirmation that the neighbor receives and processed IP traffic or neighbor solicitation requests. Otherwise, the device considers the neighbor unreachable.An IPv6 router with ND enabled can send ND information to downstream nodes. ND is optional on IPv6 devices.


Tunnels

QUESTION 1Which two support tunneling for non-IP protocols on Junos devices? (Choose two.)

A. ATM AAL2B. GRE

http://www.gratisexam.com/C. IP-IPD. ATM AAL1

Correct Answer: BCSection: TunnelsExplanation


QUESTION 2Which two support the tunneling of IP traffic on Junos devices? (Choose two.)

A. ATM AAL2B. GREC. IP-IPD. ATM AAL1

Correct Answer: BCSection: TunnelsExplanation


QUESTION 3Which two statements are true regarding GRE tunnels? (Choose two.)


A. GRE can be used to tunnel IP packets only.B. A GRE tunnel can be applied only at the physical interface level.C. GRE tunnels can be used to send non-routable packets over a public IP network.D. GRE tunnels can be used as backup links.

Correct Answer: CDSection: TunnelsExplanation


QUESTION 4Which two statements are true regarding GRE tunnel overhead? (Choose two.)

A. If the host sends a packet larger than the MTU, that packet must be dropped.B. Packets are not dropped because the router clears the DF bit for GRE traffic by default.C. Packets larger than the MTU are fragmented or dropped depending on the DF bit setting.D. You can change the tunnel MTU to avoid packet fragmentation or drops.





-- Exhibit --


Based on the exhibit, which configuration will permit end-to-end routing through the GRE tunnel for R1?

A. [edit]user@R1# show routing-options staticroute 192.168.2.1/32 next-hop gr-0/0/0.0;route 172.20.111.0/24 next-hop 192.168.1.1;

B. [edit]user@R1# show routing-options staticroute 192.168.2.1/32 next-hop gr-0/0/0.0;route 172.20.111.0/24 next-hop 172.18.1.1;

C. [edit]user@R1# show routing-options staticroute 192.168.2.1/32 next-hop 172.18.1.1;route 172.20.111.0/24 next-hop gr-0/0/0.0;

D. [edit]user@R1# show routing-options staticroute 192.168.2.1/32 next-hop 172.18.2.2;route 172.20.111.0/24 next-hop 172.18.1.1;

Correct Answer: CSection: TunnelsExplanation



Topic 2, Volume B

QUESTION 6You have configured an IP-IP tunnel between Router A and Router B

Which Junos operational mode command is used to verify that the tunnel interface is up and operational?

A. show chassis tunnel statusB. show tunnel interfaceC. show interfaces terseD. show interfaces tunnel



The "show interface terse" command displays the status fo the tunnel interface.


Click the Exhibit button

Given the network topology shown in the exhibit, you are configuring a GRE tunnel from Router A to Router C

Which interface configuration on Router A will successfully allow the tunnel to pass IPv4 traffic to Router C?


A. gr-0/0/0 { unit 0 { tunnel { source 192.168.1.1; destination 192.168.2.1; } }}

B. gr-0/0/0 { unit 0 { tunnel { source 192.168.1.1; destination 192.168.2.1; } family inet; }}

C. gr-0/0/0 { unit 0 { tunnel { source 192.168.2.1; destination 192.168.1.1; } }}

D. gr-0/0/0 { unit 0 { tunnel { source 192.168.2.1; destination 192.168.1.1; } family inet; }}

Correct Answer: BSection: TunnelsExplanation



The tunnel source and destination are specified, along with the family inet statement to enable support for IPv4 traffic.

QUESTION 8To prevent fragmentation issues across a GRE tunnel, which MTU value is recommended for the tunnel to accommodate most IP packets?

A. 1476B. 1492C. 1500D. 1524

Correct Answer: DSection: TunnelsExplanation


An MTU size of 1524 allows for packets up to 1500 bytes, along with the 4-byte GRE header and 20-byte IP header.

QUESTION 9You have configured multiple IP-IP tunnels across your network to provide connectivity to remote sites.

Which technique is used to help the IP endpoints in your network determine the optimal packet size to send across your tunnels?

A. path MTU discoveryB. fragmentation discoveryC. end-to-end MTU discoveryD. packet throughput discovery

Correct Answer: ASection: TunnelsExplanation


Path MTU discovery (PMTUD) is a technique used to determine the MTU size on a path between two endpoints. If an intermediary device on the path has an MTUsmaller than the packet sent by the tunnel endpoint, that device drops the packet and sends back an ICMP Fragmentation Needed (type 3, Code 4) messagecontaining its MTU. The received message allows the tunnel endpoint to reduce its path MTU. The tunnel endpoint repeats this discovery process until the MTU is


small enough that packets can pass through the entire path without fragmentation.

QUESTION 10Which three statements are true about GRE and IP-IP tunnels? (Choose three.)

A. All intermediary devices must have reachability to the tunnel endpoints.B. Tunnel endpoints must use the loopback interface for reachability.C. Tunnel endpoints must have a route that directs traffic into the tunnel.D. Tunnel endpoints must have a route to the remote endpoint learned by a dynamic routing protocol.E. Tunnel endpoints require a tunnel interface.

Correct Answer: ACESection: TunnelsExplanation


QUESTION 11You are asked to configure a GRE tunnel between two remote sites to support the exchange of IPv6 traffic. The two sites are separated by an IPv4 network.

Which two configuration elements are required? (Choose two.)

A. You must enable the GRE interface for IPv6 operations.B. You must increase the MTU to no less than 2500.C. You must add a static route for the remote IPv6 destination subnet with the remote tunnel endpoint as the next hop at each site.D. You must enable the GRE interface for IPv4 operations.



QUESTION 12Which three statements are true about tunneling IPv6 traffic over IPv4 networks? (Choose three.)

A. The source tunnel endpoint encapsulates the native IPv6 packet inside IPv4


B. The source tunnel endpoint disassembles the IPv6 packet and reassembles it as IPv4C. The intermediary hops are responsible for de-encapsulating and re-encapsulating the IPv4 packet to process the IPv6 payloadD. The source tunnel endpoint forwards the IPv4 network with the encapsulated IPv6 payload through the IPv4 networkE. The destination tunnel endpoint de-encapsulates the IPv6 packet and forwards/processes the packet natively

Correct Answer: ADESection: TunnelsExplanation


Tunneling requires encapsulation of the IPv6 packet within an IPv4 header. The new IPv4 packet is then forwarded across the IPv4 network to the other end of thetunnel, where the IPv4 header is removed and the IPv6 packet is either processed or forwarded.

QUESTION 13Which three protocols can be encapsulated within a GRE tunnel on a Junos device? (Choose three.)

A. AppleTalkB. Aggregated EthernetC. IPv6D. MPLSE. Ethernet

Correct Answer: ACDSection: TunnelsExplanation


GRE can encapsulate a wide variety of Network Layer protocol packet types inside IP tunnels.

QUESTION 14Which two interface names can be used within the Junos OS to reference GRE or IP-IP tunnels? (Choose two.)

A. gr-1/2/0.0B. gre-1/2/0.0C. ip-2/3/0.0


D. ipip-2/3/0.0

Correct Answer: ACSection: TunnelsExplanation


GRE interfaces are notated as gr; IP-IP interfaces are notated as ip.


Click on the exhibit

In the network shown in the exhibit, you want to configure a GRE tunnel on Router B that is destined for Router C.

Which route should be used on Router B to provide reachability to the tunnel destinations?

A. static route to the loopback address of Router AB. static route to the loopback address of Router BC. static route to the loopback address of Router CD. static route to the loopback address of Router D




A tunnel must have a valid route to the remote tunnel endpoint. In this case, Router B must have a route to Router C

QUESTION 16The gr-0/0/0.0 interface on your Junos device has a link state of up/up and you have correctly added static routes to reach the remote subnets. However, you arenot seeing traffic pass over the tunnel. What might be causing the issue?

A. The tunnel interfaces are disabledB. You have not configured keepalives on the endpointsC. The endpoints do not have valid routes to the remote tunnel endpointsD. The intermediary devices do not have valid routes to the route tunnel endpoints

Correct Answer: DSection: TunnelsExplanation


For proper tunnel operation, the intermediary devices, located in the forwarding path between the tunnel endpoints, must be able to route to each of the tunnelendpoints.

QUESTION 17Which two statements are true about IP-IP tunnels on Junos devices? (Choose two.)

A. They support only IP trafficB. Tunnel endpoints use the interface iptC. They add no additional overhead to packetsD. Each tunnel interface is point-to-point

Correct Answer: ADSection: TunnelsExplanation


IP-IP tunnels support only IP traffic, and add an additional 20-byte header to a packet. They use the interface name ip, and each interface is point-to-point

QUESTION 18Which two statements about GRE tunnels are true? (Choose two.)


A. GRE can be used to tunnel non-IP protocols, such as IPXB. GRE can provide encrypted communication C. GRE adds overhead of 16 bytes per packetD. GRE can be used to tunnel IPv6 traffic

Correct Answer: ADSection: TunnelsExplanation


GRE is a tunneling protocol that can encapsulate a wide variety of Network Layer protocol packet types inside IP tunnels, such as IPX and AppleTalk. GRE tunnelsare also commonly used to tunnel IPv6 and MPLS protocol traffic over an IP transport network.

QUESTION 19How much overhead does the IP-IP tunnel header add to an IPv4 packet?

A. 20 bytesB. 32 bytesC. 48 bytesD. 64 bytes

Correct Answer: ASection: TunnelsExplanation


IP-IP is a tunneling protocol used to encapsulate on IP packet in another IP packet. To encapsulate an IP packet using IP-IP encapsulation, an outer IP header isinserted before the packet's existing IP header. The additional IP header adds 20 bytes of overhead to the packet.

QUESTION 20Which three statements are true of GRE tunnels? (Choose three.)

A. The local tunnel endpoint must have a valid route to the remote endpointB. GRE tunnels must authenticate at both ends fo the tunnel


C. Tunnel endpoints must have a route that directs traffic into a tunnel

http://www.gratisexam.com/D. The gr interface can only route packets that are IP protocol packetsE. All intermediary devices must have a route to the tunnel endpoints

Correct Answer: ACESection: TunnelsExplanation


For proper tunnel operations, this route must resolve to the physical next hop in the end-to-end communications path and should never use a recursive route. Thetunnel endpoints also need a route with the tunnel interface as the next hop to direct traffic destined to the remote subnet into the tunnel. The intermediary devices,located in the forwarding path between the tunnel endpoints, must also be able to route each of the tunnel endpoints.


High Availability


user@R1> show configuration interfaces ge-1/1/0unit 0 { family inet { address 10.100.1.1/24 { vrrp-group 1 { virtual-address 10.200.12.254; priority 150; accept-data; track { interface ge-1/0/0 { priority-cost 40; } } } } }}

user@R2> show configuration interfaces ge-1/1/0unit 0 { family inet { address 10.100.1.2/24 { vrrp-group 1 { virtual-address 10.200.12.254; accept-data; } } }}


R1 and R2 are using VRRP for high availability.

Referring to the exhibit, which two statements are correct about the configuration? (Choose two.)



A. R2 is the backup router and will become the master router if ge-1/0/0 on R1 goes down.B. R2 is the backup router and will remain the backup router if ge-1/0/0 on R1 goes down.C. If R1 goes down, R2 will become the master and will relinquish mastership once R1 comes back online.D. If R1 goes down, R2 will become the master and will remain the master once R1 comes back online.

Correct Answer: ADSection: High AvailabilityExplanation


QUESTION 2You have recently implemented a graceful Routing-Engine switchover (GRES) and want to further reduce down time if a Routing Engine (RE) failure occurs.

Which two features can be configured on this device to reduce its downtime in this situation? (Choose two)

A. VRRPB. graceful restart (GR)C. BFDD. NSR

Correct Answer: BDSection: High AvailabilityExplanation


GRES enables a routing platform with redundant RE's to continue forwarding packets even if one RE fails; however, it does not preserve the control plane. Gracefulrestart helps to prevent disruption to the control plane. NSR saves routing protocol information by running the routing protocol process (rpd) on the backup RE.Note that NSR and graceful restart cannot be used together on a Junos device.

QUESTION 3


On a Junos device with dual Routing Engine (RE), which two statements correctly describe the expected behavior if the primary RE fails? (Choose two.)

A. The backup RE will assume the master role once the packet forwarding engine (PFE) restartsB. The backup RE will immediately assume the master roleC. The new master RE restarts the routing protocol process (rpd) and establishes any required adjacencies based on the configuration.D. The new master RE maintains the existing protocol adjacencies initially established by the previous master RE

Correct Answer: ACSection: High AvailabilityExplanation


When a Junos device has redundant RE's but no HA features enabled, and the master RE fails, the PFE restarts and all hardware and interfaces are discovered bythe new master RE. The new master RE starts rpd so that all adjacencies are aware fo the topological changes.

QUESTION 4Which three statements are true regarding the show system switchover operational mode command? (Choose three.)

A. This command can only be issued on the master Routing Engine.B. This command displays the status of graceful switchover.C. This command can only be issued on the backup Routing Engine.D. This command displays the status of the interface and process databases.E. This command displays the status of the kernel database.

Correct Answer: BCESection: High AvailabilityExplanation


QUESTION 5Which statement is true about routing instances on Junos devices?

A. Routing information cannot be shared between routing instances.B. Each routing protocol runs in a separate routing instance.C. Junos devices support only one routing instance.


D. Each routing instance is a unique grouping of routing tables, interfaces, and routing protocol parameters.

Correct Answer: DSection: High AvailabilityExplanation


QUESTION 6Which three statements are correct about VRRP? (Choose three.)

A. It requires speakers to be configured with BFD.B. It uses a virtual router MAC address for LAN communications.C. It uses multicast address 224.0.0.18.D. It is confined to the local network with a TTL of 255.E. It uses the virtual router's lo0 address for LAN communications.

Correct Answer: BCDSection: High AvailabilityExplanation


QUESTION 7On an MX Series device with dual Routing Engines, which two conditions cause a unified ISSU to fail? (Choose two.)

A. Graceful restart is disabled.B. BFD is enabled.C. GRES is disabled.D. NSR is disabled.

Correct Answer: CDSection: High AvailabilityExplanation



QUESTION 8Which standards-based election protocol facilitates redundancy in a LAN environment by eliminating a single point of failure through the use of master and backuprouters.

A. VRRPB. BFDC. graceful restartD. ISSU

Correct Answer: ASection: High AvailabilityExplanation


QUESTION 9Which high availability feature allows uninterrupted packet forwarding and temporary suppression of all routing protocol updates?

A. Virtual Router Redundancy Protocol (VRRP)B. graceful Routing Engine switchover (GRES)C. graceful restart (GR)D. nonstop active routing (NSR)

Correct Answer: BSection: High AvailabilityExplanation


QUESTION 10You have an OSPF network. On certain applications and links, you need OSPF recovery to be faster than can be provided by OSPF timers.

Which protocol would meet this requirement?



A. BFDB. OSPFv3C. GRESD. NSR



Bidirectional Forwarding Detection (BFD) accomplishes this task for a number of protocols, including OSPF.

QUESTION 11What is a requirement for link aggregation?

A. Member links must be on contiguous portsB. Member links must be on the same switch in a Virtual ChassisC. The speed of the member links must be the sameD. LACP must be configured

Correct Answer: CSection: High AvailabilityExplanation


Both the duplex and the speed of the member interfaces must match. Member links need not be contiguous nor on the same chassis. LACP does not have to beconfigured for a LAG to operate.

QUESTION 12Which two statements are true about nonstop active routing (NSR)? (Choose two.)


A. Graceful Routing Engine Switchover (GRES) must be configured for NSR to function properlyB. NSR and graceful restart can be enabled at the same timeC. NSR relies on helper support on neighboring devicesD. When NSR is enabled, the rpd process runs on the backup Routing Engine



In addition to maintaining interface and kernel information, NSR also saves routing protocol information by running the rpd process on the backup RE. By savingthis additional information, NSR is self-contained and does not rely on helper routers to assist the routing platform in restoring routing protocol information. Inaddition to enabling NSR and GRES, you should also ensure that the commit operation synchronizes the configuration file by adding the commit synchronizestatement under the [edit system] hierarchy.

QUESTION 13Which three statements are true regarding the show system switchover operational mode command? (Choose three.)

A. It must be issued on the master Routing EngineB. It displays the status of the configuration databaseC. It displays the status of peersD. It displays the status of the interface and process databasesE. It displays the status of the kernel database

Correct Answer: BCESection: High AvailabilityExplanation


The show system switchover command can be issued only on the backup RE. It displays information such as configuration database status, peer state, and kerneldatabase readiness.

QUESTION 14You have recently installed a second Routing Engine (RE) in your Junos device and implemented Graceful Routing Engine Switchover (GRES).


Which two statements correctly describe the expected behavior if the primary RE fails? (Choose two.)

A. The backup RE will assume the master role once the packet forwarding engine (PFE) restartsB. The backup RE will immediately assume the master roleC. The new master RE restarts the routing protocol process (rpd) and establishes any required adjacencies based on the configuration.D. The new master RE maintains the existing protocol adjacencies initially established by the previous master RE

Correct Answer: BCSection: High AvailabilityExplanation


Once the RE's are synchronized, the y exchange keepalives. If the backup RE does not receive a keepalive from the master RE after a specified timeout (typically 2seconds), it determines that the master RE has failed and takes mastership. When a mastership change occurs, the PFE seamlessly disconnects from the oldmaster RE and reconnects to the new master RE. The PFE does not reboot and continues forwarding traffic based on the existing forwarding table entries.

QUESTION 15What is the default value of the TTL in a VRRP advertisement?

A. 0B. 1C. 64D. 255

Correct Answer: DSection: High AvailabilityExplanation


The VRRP advertisement packet uses a time-to-live (TTL) value of 255 and cannot be forwarded beyond the local subnet on which it is sent. This value cannot beadjusted, and any packet that has a TTL value other than 255 is discarded.

QUESTION 16Which statement is true about link aggregation?

A. It facilitates control plane redundancy through link aggregation


B. It provides an active-passive failover mechanism for redundant Layer 2 linksC. It combines multiple Ethernet interfaces into a single link-layer interfaceD. It combines multiple Ethernet interfaces into a multilink-layer interface.

Correct Answer: CSection: High AvailabilityExplanation


The IEEE 802.3ad link aggregation specification enables multiple Ethernet interfaces to be grouped together and form a single link layer interface, also known as alink aggregation group (LAG) or bundle. The physical links participating in a LAG are known as member links. LAGs are commonly used to aggregate trunk linksbetween access and aggregation switches.

QUESTION 17Which two statements are true about unified in-service software upgrade (ISSU)? (Choose two.)

A. Unified ISSU is supported only on dual Routing Engine (RE) platformsB. To perform a unified ISSU, it is not necessary for the master RE and backup RE to be running the same version of the Junos OSC. Unified ISSUE causes minimal disruption on both the control and forwarding planesD. Graceful Routing Engine Switchover (GRES) and nonstop active routing (NSR) must be enabled to perform a unified ISSU



Unified ISSU enables you to upgrade between two different Junos OS releases with no disruption on the control plane and with minimal disruption of traffic. UnifiedISSUE is supported only on dual RE platforms. In addition, GRES and NSR must be enabled. The RE's must be running the same software release before you canperform a unified ISSU.

QUESTION 18Which command verifies that graceful Routing Engine Switchover (GRES) is operational?

A. show system switchover on the master REB. show system switchover on the backup REC. show task replication on the master RE


D. show task replication on the backup RE

Correct Answer: BSection: High AvailabilityExplanation


The show system switchover command, which is used to verify whether graceful Routing Engine switchover is enabled and that the databases are synchronized,must be issued on the backup RE to get the desired output.

QUESTION 19Which three statements about nonstop active routing (NSR) are correct? (Choose three.)

A. NSR uses the graceful Routing Engine switchover infrastructureB. NSR and graceful restart work together to reduce downtime during a Routing Engine failureC. NSR preservers routing information and protocol sessions on both Routing EnginesD. NSR requires that both Routing Engines run the same version of softwareE. NSR enables chassisd on both Routing Engines to allow for a smooth transition during a failure

Correct Answer: ACDSection: High AvailabilityExplanation


- NSR uses the graceful Routing Engine switchover infrastructure.- NSR preservers routing information and protocol sessions on both Routing Engines- NSR requires that both Routing Engines run the same version of software

NSR and graceful restart cannot be configured or used together

QUESTION 20What is the default interval for a VRRP advertisement?

A. 1 secondB. 2 secondsC. 10 seconds


D. 30 seconds


Explanation/Reference:Explanations

The default interval for VRRP advertisements is 1 second. You can modify this interval to a value in the range of 1-255 seconds. If subsecond VRRPadvertisements are required, configure the fast-interval parameter with a range of 100-999 milliseconds. Note that to use this feature, all participating VRRP routersmust support the option.


Documents

JN0-360 juniper - GRATIS EXAM · Whenever switch updates an entry in the MAC address table, the switch resets the timer for that entry. Timers are used in aging process of old entries