Testking Cisco 642-832 formatted - GRATIS EXAM...2012/01/06 · Although the loopback interface is using a /24 subnet mask, EIGRP summarizes at network boundaries by default so the

Testking Cisco 642-832_formatted

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Cisco 642-832: Practice Exam

Exam A

QUESTION 1Which two statements about the Cisco Aironet Desktop Utility (ADU) are true? (Select two)

A. The Aironet Desktop Utility (ADU) profile manager feature can create and manage only one profile for thewireless client adapter.

B. The Aironet Desktop Utility (ADU) can support only one wireless client adapter installed and used at a time.C. The Aironet Desktop Utility (ADU) can be used to establish the association between the client adapter and

the access point, manage authentication to the wireless network, and enable encryption.D. The Aironet Desktop Utility (ADU) and the Microsoft Wireless Configuration Manager can be used at the

same time to configure the wireless client adapter.

Correct Answer: BCSection: (none)Explanation

Explanation/Reference:Explanation:You can configure your Cisco Aironet Wireless LAN Client Adapter through the Cisco ADU or a third-party tool,such as the Microsoft Wireless Configuration Manager. Because third-party tools may not provide all thefunctionality available in ADU, Cisco recommends that you use ADU. The Aironet Desktop Utility (ADU) cansupport only one wireless client adapter as well as Aironet Desktop Utility establish the association between theclient adapter and Access Point, allows to authenticate wireless client, allows to configure encryption by settingstatic WEP, WPA/WPA2 passphrase.

BeITCertified.comSection 3: Perform routine IOS device maintenance (0 Questions)

Section 4: Isolate sub-optimal internetwork operation at the correctly defined OSI Model layer (2 Questions)

QUESTION 2At which layer of the OSI model does the Spanning Tree Protocol (STP) operate at?

A. Layer 5"Pass Any Exam. Any Time." - Guaranteed 2Cisco 642-832: Practice Exam

B. Layer 4C. Layer 3D. Layer 2E. Layer 1

Correct Answer: DSection: (none)Explanation

Explanation/Reference:Explanation:Spanning-Tree Protocol (STP) is a Layer 2 (L2) protocol designed to run on bridges and switches. Thespecification for STP is called 802.1d. The main purpose of STP is to ensure that you do not run into a loopsituation when you have redundant paths in your network. Loops are deadly to a network.

QUESTION 3In computer networking a multicast address is an identifier for a group of hosts that have joined a multicastgroup. Multicast addressing can be used in the Link Layer (OSI Layer 2), such as Ethernet Multicast, as well asat the Internet Layer (OSI Layer 3) as IPv4 or IPv6 Multicast. Which two descriptions are correct regardingmulticast addressing?

A. The first 23 bits of the multicast MAC address are 0x01-00-5E. This is a reserved value that indicates amulticast application.

B. The last 3 bytes (24 bits) of the multicast MAC address are 0x01-00-5E. This is a reserved value thatindicates a multicast application.

C. To calculate the Layer 2 multicast address, the host maps the last 23 bits of the IP address into the last 24bits of the MAC address. The high-order bit is set to 0.

D. The first 3 bytes (24 bits) of the multicast MAC address are 0x01-00-5E. This is a reservedBeITCertified.comvalue that indicates a multicast application.

Correct Answer: CDSection: (none)Explanation

Explanation/Reference:Explanation:The point of this question is the form of multicast MAC address, and the conversion between the multicast MACaddress and IP address.

The multicast MAC address is 6 bytes(48 bits), the first 3 bytes (24 bits) of the multicast MAC address are0x01-00-5E, the last 3 bytes(24 bits) of the multicast MAC address =0 + 23 bit(the last 23 bit of the IP address)."0x01-00-5E" is a reserved value that indicates a multicast application.So option B and D are correct.

QUESTION 4"Pass Any Exam. Any Time." - Guaranteed 3Cisco 642-832: Practice Exam


EIGRP is being used as the routing protocol on the company network. While troubleshooting some networkconnectivity issues, you notice a large number of EIGRP SIA (Stuck in Active) messages.What causes these SIA routes? (Select two)

A. The neighboring router stops receiving ACK packets from this router.B. The neighboring router starts receiving route updates from this router.C. The neighboring router is too busy to answer the query (generally caused by high CPU utilization).D. The neighboring router is having memory problems and cannot allocate the memory to process the query or

build the reply packet.


Explanation/Reference:Explanation:SIA routes are due to the fact that reply packets are not received. This could be caused by a router which isunable to send reply packets. The router could have reached the limit of its capacity, or it could bemalfunctioning.Incorrect Answers:A: Missing replies, not missing ACKs, cause SIA.

B: Routes updates do not cause SIA.Notes: If a router does not receive a reply to all outstanding queries within3 minutes, the route goes to the stuck in active (SIA) state. The router then resets the neighbors that fail toreply by going active on all routes known through that neighbor, and it re- advertises all routes to thatneighbor.Reference: Enhanced Interior Gateway Routing Protocolhttp://www.cisco.com/warp/public/103/eigrp3.html

QUESTION 5BeITCertified.comPart of the routing table of router R1 is displayed below:

S 62.99.153.0/24 [1/0] via 209.177.64.130172.209.12.0/32 is subnetted, 1 subnetsD EX 172.209.1[170/2590720] via 209.179.2.114, 06:47:28, Serial0/0/0.1239 62.113.17.0/24 is variably subnetted, 2 subnets, 2masks D EX 99.3.215.0/24[170/27316] via 209.180.96.45, 09:52:10, FastEthernet11/0/0 [170/27316] via 209.180.96.44, 09:52:10,FastEthernet11/0/0 25.248.17.0/24[90/1512111] via 209.179.66.25, 10:33:13, Serial0/0/0.1400001 [90/1512111] via 209.179.66.41, 10:33:13,Serial0/0/0.1402001 62.113.1.0/24 is variably subnetted, 12 subnets, 2 masks D 62.113.1.227/32

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[90/2611727] via 209.180.96.45, 10:33:13, FastEthernet1/0/0 [90/2611727] via 209.180.96.44, 10:33:13,FastEthernet1/0/0 S* 0.0.0.0/0 [1/0] via 209.180.96.14

From analyzing the above command output, what is the administrative distance of the external EIGRP routes?

A. 24B. 32C. 90D. 170E. 27316F. None of the other alternatives apply


Explanation/Reference:Explanation:By default an external EIGRP route has a value of 170. By examining the exhibit we see that this default valueof the external EIGRP routes (see D-EX in exhibit) indeed is set to 170. The first value within the bracketsdisplay the AD, so with a value of [170/27316] the AD is 170 and the metric of the route is 27316.Incorrect Answers:A: This is the subnet mask used for some of the routes in the table.B: This is the subnet mask used for some of the routes in the table.C: This is the AD of the internal EIGRP routes, which is the defaultE: This is the EIGRP metric of the external EIGRP routes.Reference: What Is Administrative Distance?http://www.cisco.com/warp/public/105/admin_distance.html

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QUESTION 6The network is shown below, along with the relevant router configurations:

R1# show runinterface Loopback0ip address 10.10.10.1 255.255.255.0!interface Ethernet0ip address 172.29.1.1 255.255.255.0media-type 10BaseT"Pass Any Exam. Any Time." - Guaranteed 5Cisco 642-832: Practice Exam

!!router eigrp 999redistribute connectednetwork 172.29.0.0auto-summaryno eigrp log-neighbor-changes!ip classlessno ip http server

R2# show runinterface Ethernet0ip address 172.29.1.2 255.255.255.0media-type 10BaseT!interface Ethernet1ip address 172.19.2.2 255.255.255.0media-type 10BaseT!router eigrp 999network 172.19.0.0network 172.29.0.0!ip classlessno ip http server

BeITCertified.comR3# show runinterface Ethernet1/0ip address 172.19.2.3 255.255.255.0!router eigrp 999network 172.19.0.0auto-summaryno eigrp log-neighbor-changes!ip classlessip http server

With the topology found in the graphic, what will the R1 loopback 0 be in the R3 routing table?

A. It will show up in the routing table as D 10.0.0/8."Pass Any Exam. Any Time." - Guaranteed 6Cisco 642-832: Practice Exam

B. It will show up in the routing table as D EX 10.0.0.0/8.C. It will show up in the routing table as D 10.0.0./24.D. It will not show up in R3 routing table because there is no network command on R1.

Correct Answer: BSection: (none)Explanation

Explanation/Reference:Explanation:Because router R1 is configured with route redistribution, it will redistribute the connected loopback network intoEIGRP. Because redistributed routes will show up as external EIGRP routes in the routing table, choice B iscorrect. Although the loopback interface is using a /24 subnet mask, EIGRP summarizes at network boundariesby default so the network will appear as the class A network of 10.0.0.0/8 in the routing table of the otherrouters.Incorrect Answers:A: The route will be external, since it was redistributed into EIGRP.C: It will be external because of redistribution, and it will also be summarized since that is the default behaviorof EIGRP.D: Although it was not configured under the EIGRP network command, it would be redistributed because it is aconnected route.

QUESTION 7The EIGRP network is displayed in the following topology diagram:

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You work as a network technician. Study the exhibits carefully. If the command "variance 3" was added to theEIGRP configuration of R5, which path or paths would be chosen to route traffic from R5 to network X?

A. R5-R2-R1B. R5-R2-R1 and R5-R3-R1.C. R5-R3-R1 and R5-R4-R1.


D. R5-R2-R1,R5-R3-R1, and R5-R4-R1.


Explanation/Reference:Explanation:Every routing protocol supports equal cost path load balancing. In addition, Interior Gateway Routing Protocol(IGRP) and EIGRP also support unequal cost path load balancing. Use the variance n command in order toinstruct the router to include routes with a metric of less than n times the minimum metric route for thatdestination. The variable n can take a value between 1 and 128. The default is 1, which means equal cost loadbalancing. Traffic is also distributed among the links with unequal costs, proportionately, with respect to themetric. In this question the variance 3 command is used . In this instance, R5 can get to Net X using the pathR5-R3 = metric of 10, and R3-R1 = 10 as well with the FD between R5 - R1 being 10 + 10 =20. Therefore, we can load balance on any route that had an FD of 3x the successor, or 3x20, which is 60Important Note: If a path does not meet the feasibility condition, the path is not used in load balancing. This iswhy chose D is wrong as this path has an Advertised Distance of 25 which is greater than the successors FD.The link below refers to an example that is nearly identical to the example in this question, except theirs used avariance of 2 and this question used a variance of 3.Reference:http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a008009437d.shtml

QUESTION 8The following command was issued on Router 2:

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Given the above output shown above, which statement is true?

A. 192.168.1.0 is a redistributed route into EIGRP.B. 192.168.1.0 is a summarized route.C. 192.168.1.0 is a static route.D. 192.168.1.0 is equal path load balancing with 172.16.1.0.E. None of the other alternatives apply

Correct Answer: ASection: (none)Explanation

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Explanation:

When EIGRP learns the routing information from the different routing protocol it uses D EX symbol to indicatethat this routing information has learned from other routing protocol.

QUESTION 9A network administrator is troubleshooting an EIGRP connection between RouterA, IP address 10.1.2.1, andRouterB, IP address 10.1.2.2. Given the debug output on RouterA, which two statements are true?

A. RouterA received a hello packet with mismatched metric-calculation mechanisms.B. RouterA received a hello packet with mismatched authentication parameters.C. RouterA will form an adjacency with RouterB.D. RouterA received a hello packet with mismatched autonomous system numbers.E. RouterA received a hello packet with mismatched hello timers.F. RouterA will not form an adjacency with RouterB.

Correct Answer: AFSection: (none)Explanation

Explanation/Reference:Explanation:Metrics are the mathematics used to select a route. The higher the metric associated with a route,BeITCertified.comthe less desirable it is. For EIGRP, the Bellman-Ford algorithm uses the following equation and creates theoverall 24-bit metric assigned to a route:

(reliability + K4)]The elements in this equation are as follows:* By default, K1 = K3 = 1, K2 = K4 = K5 = 0. Therefore, by default, the metric formula reduces to:

metric = bandwidth + delayK Values should be same to become the EIGRP neighbors.

QUESTION 10Study the exhibit below carefully:


If the configuration shown below is added to Router1, which three route entries will EIGRP advertise toneighboring routers? (Select three)

router eigrp 10network 10.0.0.0eigrp stub

A. 192.168.20.0/24B. 10.1.2.0/24C. 10.1.1.0/24D. 10.1.3.0/24E. 10.0.0.0/8

Correct Answer: CDESection: (none)Explanation

Explanation/Reference:Explanation:The Enhanced Interior Gateway Routing Protocol (EIGRP) Stub Routing feature improves network stability,reduces resource utilization, and simplifies stub router configuration. Stub routing is commonly used in a huband spoke network topology. In a hub and spoke network, BeITCertified.comone or more end (stub) networks are connected to a remote router (the spoke) that is connected to one or moredistribution routers (the hub). The remote router is adjacent only to one or more distribution routers. The onlyroute for IP traffic to follow into the remote router is through a distribution router. This type of configuration iscommonly used in WAN topologies where the distribution router is directly connected to a WAN. Thedistribution router can be connected to many more remote routers. Often, the distribution router will beconnected to 100 or more remote routers. In a hub and spoke topology, the remote router must forward allnonlocal traffic to a distribution router, so it becomes unnecessary for the remote router to hold a completerouting table. Generally, the distribution router need not send anything more than a default route to the remoterouter.When using the EIGRP Stub Routing feature, you need to configure the distribution and remote routers to useEIGRP, and to configure only the remote router as a stub. Only specified routes are propagated from theremote (stub) router. The router responds to queries for summaries, connected routes, redistributed staticroutes, external routes, and internal routes with the message "inaccessible." A router that is configured as astub will send a special peer information packet to all neighboring routers to report its status as a stub router."Pass Any Exam. Any Time." - Guaranteed 10Cisco 642-832: Practice Exam

Any neighbor that receives a packet informing it of the stub status will not query the stub router for any routes,and a router that has a stub peer will not query that peer. The stub router will depend on the distribution routerto send the proper updates to all peers.

QUESTION 11Refer to the exhibit. EIGRP has been configured on routers R1 and R2. However, R1 does not show R2 as aneighbor and does not accept routing updates from R2. What could be the cause of the problem?

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A. The no auto-summary command has not been issued under the EIGRP process on both routers.B. Interface E0 on router R1 has not been configured with a secondary IP address of 10.1.2.1/24.C. EIGRP cannot exchange routing updates with a neighbor's router interface that is configured with two IP

addresses.D. EIGRP cannot form neighbor relationship and exchange routing updates with a secondary address.


Explanation/Reference:Explanation:Remember that simple distance vector routers do not establish any relationship with their neighbors. RIP andIGRP routers merely broadcast or multicast updates on configured interfaces. In contrast, EIGRP routersactively establish relationships with their neighbors, much the same way that OSPF routers do.EIGRP routers establish adjacencies with neighbor routers by using small hello packets. Hellos "Pass AnyExam. Any Time." - Guaranteed 11Cisco 642-832: Practice Exam

are sent by default every five seconds. An EIGRP router assumes that as long as it is receiving hello packetsfrom known neighbors, those neighbors (and their routes) remain viable. By forming adjacencies, EIGRProuters do the following: Dynamically learn of new routes that join their network Identify routers that becomeeither unreachable or inoperable Rediscover routers that had previously been unreachable

QUESTION 12

While troubleshooting an EIGRP routing problem you notice that one of the company routers have generated alarge number of SIA messages. What are two possible causes for EIGRP Stuck-In- Active routes? (Select two)

A. Some query or reply packets are lost between the routers.B. The neighboring router starts receiving route updates from this router.C. A failure causes traffic on a link between two neighboring routers to flow in only one direction (unidirectional

link).D. The neighboring router stops receiving ACK packets from this router.

Correct Answer: ACSection: (none)Explanation

Explanation/Reference:Explanation:The acknowledgement does not reach the destination or they are too delayed. This is normally due to too manyrouting topology changes, or a router with insufficient memory. Note: In some circumstances, it takes a verylong time for a query to be answered. So long, in fact, that the router that issued the query gives up and clearsits connection to the router that isn't answering, effectively restarting the neighbor session. This is known as astuck in active (SIA) route. The most basic SIA routes occur when it simply takes too long for a query to reachthe other BeITCertified.comend of the network and for a reply to travel back.Incorrect Answers:B: Does not apply to SIA. This is the normal operation of EIGRP.D: Ack packets don't reply to Queries, only Replydo.Reference:http://www.cisco.com/warp/public/103/eigrp3.html

QUESTION 13EIGRP uses five generic packet types (hello, updates, queries, replies, acknowledgements). If you wished toview the statistics for these packets, which IOS command should you use?

A. debug eigrp packetsB. show ip eigrp trafficC. show ip eigrp topology


D. show ip eigrp neighbors


Explanation/Reference:Explanation:The show ip eigrp traffic command displays the number of Enhanced IGRP (EIGRP) packets sent andreceived.Example:The following is sample output from the show ip eigrp traffic command:Router# show ip eigrp traffic

IP-EIGRP Traffic Statistics for process 77Hellos sent/received: 218/205Updates sent/received: 7/23Queries sent/received: 2/0Replies sent/received: 0/2Acks sent/received: 21/14

Reference

:http://www.cisco.com/en/US/products/sw/iosswrel/ps1828/products_command_reference_chapter09186a00800ca5a9.html#wp1018815

QUESTION 14While troubleshooting a routing problem on the company EIGRP network you discover that one of the routers isfailing to establish adjacencies with its neighbor. What is a likely cause of this problem between neighbors?(Select two)BeITCertified.com

A. The K-values do not match.B. The hold times do not match.C. The hello times do not match.D. The AS numbers do not match.

Correct Answer: ADSection: (none)Explanation

Explanation/Reference:Explanation:Peer relationships and adjacencies between routers will not be formed between EIGRP routers if the neighborresides in a different autonomous system or if the metric-calculation mechanism (K values) is misaligned forthat link.Incorrect Answers:B: It is possible for two routers to become EIGRP neighbors even though the hello and hold timers do notmatch.Section 2: Troubleshoot OSPF(9 Questions)C: It is possible for two routers to become EIGRP neighbors even though the hello and hold timers


do not match.Section 2: Troubleshoot OSPF(9 Questions)

QUESTION 15

A.B.C.D.

Correct Answer: Section: (none)Explanation

Explanation/Reference:

QUESTION 16Refer to the exhibit. On the basis of the information presented, which statement is true?

A. OSPF router 5.0.0.2 is an ABR.B. Network 6.0.0.0/8 was learned from an OSPF neighbor within the area.C. The default route is learned from an OSPF neighbor.D. A default route is configured on the local router.


Explanation/Reference:Explanation:In this example, the network 6.0.0.0/8 shows that it was leaned via IA, or Inter-area. Since this came from aneighbor in a different area, then the neighbor router at 5.0.0.2 must be an ABR.The various route types used by OSPF are:

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QUESTION 17DR (Designated Router) is for environments where many routers on the same network such as Ethernet. In thefollowing presented network, all routers are reloaded simultaneously, and DR is selected as expected. What isthe CK-RTC status?


A. 2WAY/BDRB. FULL/BDRC. 2WAY/DROTHERD. 2WAY/DRE. FULL/DROTHERF. FULL/DRG. None of the other alternatives apply

Correct Answer: ESection: (none)Explanation

Explanation/Reference:Explanation:BeITCertified.comHow OSPF Forms Its Neighbors :In this example topology, all routers are running Open Shortest Path First (OSPF) over the Ethernet network:


This is sample output of the show ip ospf neighbor command on R7 and R8:R7# show ip ospf neighbor

Neighbor ID Pri State Dead Time Address Interface170.170.3.4 1 2WAY/DROTHER 00:00:34 170.170.3.4 Ethernet0 170.170.3.3 1 2WAY/DROTHER 00:00:34170.170.3.3 Ethernet0 170.170.3.8 1 FULL/DR 00:00:32 170.170.3.8 Ethernet0170.170.3.2 1 FULL/BDR 00:00:39 170.170.3.2 Ethernet0

Notice that R7 establishes full adjacency only with the Designated Router (DR) and the Backup DesignatedRouter (BDR). All other routers have a two-way adjacency established. This is normal behavior for OSPF.

In this case, the "show ip ospf neighbor"is performed on R4. R4 is the DR (due to higher router ID)so it will haveFULL adjacency with all routers including R2. If the "show ip ospf neighbor" had been performed on R1, then itwould show 2way/drother with R2.

Router4# show ip ospf neighborNeighbor ID Pri State Dead Time Address Interface 192.168.1.1 1 FULL/DROTHER 00:00:31 192.168.1.1FastEthernet0/0 192.168.1.2 1 FULL/DROTHER 00:00:31 192.168.1.2 FastEthernet0/0 192.168.1.3 1 FULL/BDR 00:00:31 192.168.1.3 FastEthernet0/0 Router1# show ip ospf neighborNeighbor ID Pri State Dead Time Address Interface 192.168.1.2 1 2WAY/DROTHER 00:00:35 192.168.1.2FastEthernet0/0 192.168.1.3 1 FULL/BDR 00:00:35 192.168.1.3 FastEthernet0/0 192.168.1.4 1 FULL/DR00:00:35 192.168.1.4 FastEthernet0/0

Reference:BeITCertified.comwww.cisco.com/en/US/customer/tech/tk365/technologies_tech_note09186a0080094059.shtml

QUESTION 18While troubleshooting some connectivity issues, you issue the "show ip ospf database" in order to examine thelink state database. Which three of the statements below are true regarding the OSPF link state database?(Select three)

A. Each router has an identical link state database.B. External routes are imported into a separate link state database.C. Synchronization of link state databases is maintained via flooding of LSAs.D. Information in the link state database is used to build a routing table by calculating a shortestpath tree.E. By default, link state databases are refreshed every 10 minutes in the absence of topology changes.


Correct Answer: ACD

Section: (none)Explanation

Explanation/Reference:Explanation:The Link state database is a collection of link state advertisement for all routers and networks. Each router inthe OSPF network maintains an identical database. LSA flooding occurs whenever there is a change in theOSPF topology, ensuring that the databases are synchronized. OSPF also uses the SPF algorithm to build thedatabase tables.Incorrect Answers:B: Only one link state database is maintained, and it is used for all OSPF routes.E: The default refresh time is 30 minutes.Reference: Building Scalable Cisco Networks (Cisco Press) page178.

QUESTION 19Which command should you use to verify what networks are being routed by a given OSPF process?

A. show ip ospfB. show ip routeC. show ip protocolD. show ip ospf databaseE. None of the other alternatives apply

Correct Answer: CSection: (none)Explanation

Explanation/Reference:Explanation:The information displayed by the show ip protocols command is useful in debugging routing BeITCertified.comoperations. Information in the Routing Information Sources field of the show ip protocols output can help youidentify a router suspected of delivering bad routing information. For OSPF routers, this command will displaythe routed networks.Incorrect Answers:A: To display general information about Open Shortest Path First (OSPF) routing processes, use the show ipospf command in EXEC mode. This command will display the areas assigned and other useful information, butnot the networks being routed.Example:R1# show ip ospfRouting Process "ospf 201" with ID192.42.110.200Supports only single TOS(TOS0) routeIt is an area border and autonomous system boundaryrouterRedistributing External Routes from, igrp 200 with metric mapped to 2, includes subnets in redistributionrip with metric mapped to 2 igrp 2 with metric mapped to 100 igrp 32 with metric mapped to 1Number of areasin this router is 3Area 192.42.110.0 Number of interfaces in this area is 1 Area has simple passwordauthentication SPF algorithm executed 6 timesB: This will display the active routing table, but not the networks that are being routed.D: The OSPF database does not display the networks being routed.


QUESTION 20You have a multi-area OSPF network and you're concerned because one of the sites is having connectivityproblem to resources in a different area. Which IOS privileged mode command would you enter to confirm thatyour network: A) has a path to its ABR, B) has a path to its ASBR, and C) the SPF calculation is functional?

A. show ip protocolsB. show running-configC. show ip ospf neighborD. show ip ospf border-routers


Explanation/Reference:Explanation:The show ip ospf border-routers command displays the internal OSPF routing table entries to an area borderrouter (ABR) and autonomous system boundary router (ASBR). The SPF No in the output is the internalnumber of SPF calculation that installs this route.Example: Router R# show ip ospf border-routers

OSPF Process 109 internal Routing Table

Destination Next Hop Cost Type Rte Type Area SPF No

160.89.97.53 144.144.1.53 10 ABR INTRA 0.0.0.3 3160.89.103.51 160.89.96.51 10 ABR INTRA 0.0.0.3 3BeITCertified.com160.89.103.52 160.89.96.51 20 ASBR INTER 0.0.0.3 3160.89.103.52 144.144.1.53 22 ASBR INTER 0.0.0.3 3Incorrect Answers:A: The show ip protocols command only displays routing protocol parameters and current timer values.B: The show running-config command displays the currently used configuration mode. The required informationwill not be displayed.C: The show ip ospf neighbor command displays OSPF-neighbor information on a per-interface basis. It doesnot include ABR, ASBR or SPF information.

QUESTION 21An OSPF link can be in multiple states at any given moment (ie. Exstart, exchange, full). Which two IOScommands let you view the state of the link? (Select two)


A. show ip ospfB. show ip protocolsC. show ip ospf neighborD. show ip ospf interface


Explanation/Reference:Explanation:The link state exstart is an OSPF link state (see note below). We need retrieve OSPF link state information.C: The output of the show ip ospf neighbor command is used To display OSPF-neighbor information on a per-interface basis. It includes link state information.D: The show ip ospf interface command is used to display OSPF-related interface information for a particularinterface. This includes the link state of the specified interface.

Note: exstart state: After two OSPF neighboring routers establish bi-directional communication and completeDR/BDR election (on multi-access networks), the routers transition to the exstart state.Incorrect Answers:A: The show ip ospf command is used to display general information about OSPF routing processes. However,it does not include any link state information.B: The command "show ip protocols" displays the parameters andcurrent state of the active routing protocol process. It does not show any link state information.

QUESTION 22Which command would display OSPF parameters such as filters, default metric, maximum paths,BeITCertified.comand number of areas configured on a router?

A. show ip protocolB. show ip routeC. show ip ospf interfaceD. show ip ospfE. show ip interfaceF. None of the other alternatives apply


Explanation/Reference:Explanation:The "show ip protocol" command displays values about routing timers and network information associated withthe entire router . This includes, the AS number associated with the routing process, number of areasconfigured on the router, the metric, and the maximum paths.


QUESTION 23Exhibit:

You work as a network technician. You trainee shows you the IOS command output displayed in the exhibit.What command did Tess use to produce this output?

A. show ip RIPB. show ipv6 ospfC. show ip ospf

D. show ip ospf interfaceE. show ipv6 ospf interface

BeITCertified.comF. show ipv4 ospfG. None of the other alternatives apply


Explanation/Reference:Explanation:In this case we can see that OSPFv3 is being used, and since OSPFv3 is used exclusively for IPv6 networkswe know that the correct answer must be "show ipv6 ospf." To display general information about Open ShortestPath First (OSPF) routing processes, use the show ipv6 ospf command in user EXEC or privileged EXECmode.Example:The following is sample output from the show ipv6 ospf command:Router# show ipv6 ospf

Routing Process "ospfv3 1" with ID 10.10.10.1SPF schedule delay 5 secs, Hold time between two SPFs 10 secs


Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs LSA group pacing timer 240 secsInterface flood pacing timer 33 msecsRetransmission pacing timer 66 msecsNumber of external LSA 0. Checksum Sum 0x000000Number of areas in this router is 1. 1 normal 0 stub 0 nssa Area BACKBONE(0)Number of interfaces in this area is 1MD5 Authentication, SPI 1000SPF algorithm executed 2 timesNumber of LSA 5. Checksum Sum 0x02A005Number of DCbitless LSA 0Number of indication LSA 0Number of DoNotAge LSA 0Flood list length 0

Reference: http://www.cisco.com/en/US/docs/ios/12_3t/ipv6/ipv6_15g.html#wp2139460

QUESTION 24Which IOS command would you use to find out which networks are routed by a particular OSPF process?

A. show ospfB. show ip routeC. show ip protocols

BeITCertified.comD. show ip ospf databaseE. None of the other alternatives apply


Explanation/Reference:

Explanation:The show ip protocols command display current routing protocols. It displays the parameters and current stateof the active routing protocol process. The output includes a list of the networks routing for individual ospfprocesses.

Sample output:Rt Router # show ip protocolsRouting Protocol is "ospf 200"Sending updates every 0 secondsInvalid after 0 seconds, hold down 0, flushed after 0Outgoing update filter list for all interfaces is not set


Incoming update filter list for all interfaces is not set Redistributing: ospf 200Routing for Networks:172.6.31.5/32Routing Information Sources:Gateway Distance Last UpdateDistance: (default is 110)Incorrect Answers:A: The show ospf command displays summary information regarding the global OSPF configuration.B: The show ip route command displays the IP routing table.D: The show ip ospf database command displays the contents of the topological database maintained by therouter. The command also shows the router ID and the OSPF process ID. However, the output does notinclude the networks routing for individual ospf processes.Section 3:Troubleshoot eBGP(21 Questions)

QUESTION 25A problem was reported that the 10.10.10.0/24 prefix was not injected into the local BGP table on a Companyrouter named R1. The following information is available from this router:

R1 Configuration:

router bgp 65001network 10.0.0.0neighbor 172.16.1.1 remote-as 65002BeITCertified.comno auto-summary

Routing table information:

show ip route | include 10O 10.10.10.0/24 [110/11] via 192.168.1.1, 2d00h, Ethernet0/0

Why is this prefix not in the local BGP table of the R1?

A. The 172.16.1.1 neighbor is down.B. The prefix 10.10.10.0/24 is not a 'connected' route.C. This route is not a BGP learned route.D. The network command is wrong.E. None of the other alternatives apply



Explanation/Reference:Explanation:The network command is used with IGPs, such as RIP, to determine the interfaces on which to send andreceive updates. The command also indicates which directly connected networks to advertise. However, whenconfiguring BGP, the network command does not affect what interfaces BGP runs on. Therefore, configuringjust a network statement will not establish a BGP neighbor relationship. This is a major difference betweenBGP and IGPs. The network statement follows this syntax:Router(config-router)# network network-number [ mask network-mask ]

In BGP, the network command tells the BGP process what locally learned networks to advertise. The networkscan be connected routes, static routes, or routes learned by way of a dynamic routing protocol, such as RIP.These networks must also exist in the routing table of the local router or they will not be sent out in updates.The mask keyword can be used with the network command to specify individual subnets. Routes learned by theBGP process are propagated by default but are often filtered by a routing policy. In this example, the correctsyntax should be "network 10.10.10.0 mask 255.255.255.0" under the BGP routing process. Without the correctsubnet mask specified, the route will not get injected into the BGP routing table, even if it is learned via an IGP.In this case, the route is known via OSPF.

QUESTION 26Which IOS command would you enter if you wanted to view a list of IBGP and EBGP neighbor relationshipsthat are configured?

A. show ip bgpBeITCertified.com

B. show ip bgp pathsC. show ip bgp peersD. show ip bgp summaryE. show ip bgp protocols


Explanation/Reference:Explanation:The show ip bgp summary command displays the status of all BGP connections. Neighbors with correspondingAS values will be listed; both interior and external.Incorrect Answers:A: The show ip bgp command displays routes in the BGP routing table, not the neighbors.B: The show ip bgp paths command is used to display all the BGP paths in the database.However, it does not list the neighbors.C: There is no suchcommand.Reference:http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/12cgcr/np1


_r/1rprt1/1rbgp.htmE: There is no suchcommand.Reference:http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/12cgcr/np1_r/1rprt1/1rbgp.htm

QUESTION 27Which two of the following descriptions are correct according to the displayed output of the command show ipbgp summary? (Choose two.)

A. The BGP session to the 10.1.1.1 neighbor is established.B. The router is trying to create a BGP peering session with the 10.1.1.1 neighbor.C. The BGP session to the 10.3.3.3 neighbor is created, but the router received no BGP routing updates from

the 10.3.3.3 neighbor.D. The router is attempting to establish a BGP peering session with the 10.2.2.2 neighbor.


Explanation/Reference:Explanation:BeITCertified.comShow ip bgp summary command displays the summary of all BGP connections. The six states of the BGP FSMare described as follows:* Idle - Idle is the first state of a BGP connection. BGP is waiting for a start event. It is normally initiated by anadministrator or a network event. At the start event, BGP initializes its resources and resets a connect retrytimer. Then it starts listening for a TCP notice that BGP can transition back to Idle from any other state in caseof errors.* Connect - In the Connect state, BGP is waiting for the TCP connection to be completed. If the TCPconnection is successful, the state transitions to OpenSent. If the TCP connection fails, the state transitions tothe Active state, and the router tries to connect again. If the connect retry timer expires, the state remains in theConnect state, the timer is reset, and a TCP connection is initiated. In case of any other event, initiated by thesystem or the administrator, the state returns to Idle.* Active - In the Active state, BGP is trying to acquire a peer by initiating a TCP connection. If it is successful, ittransitions to OpenSent. If the connect retry timer expires, BGP restarts the connect timer and returns to theConnect state. While active, BGP is still listening for a connection


that may be initiated from another peer. The state may go back to Idle in case of other events, such as a stopevent initiated by the system or the operator. In general, a neighbor state that is switching between "Connect"and "Active" is an indication that something is wrong and that there are problems with the TCP connection. Itcould be because of many TCP retransmissions, or the incapability of a neighbor to reach the IP address of itspeer.* OpenSent - In the OpenSent state, BGP is waiting for an open message from its peer. The open message ischecked for correctness. In case of errors, such as an incompatible version number or an unacceptable AS, thesystem sends an error notification message and goes back to idle. If there are no errors, BGP starts sendingkeepalive messages and resets the keepalive timer. At this stage, the hold time is negotiated and the smallervalue is taken. If the negotiated hold time is zero (0), the hold timer and the keepalive timer are not restarted. Atthe OpenSent state, BGP recognizes whether the peer belongs to the same AS or to a different AS. BGP doesthis by comparing its AS number to the AS number of its peer. A same AS is an IBGP peer and a different AS isan EBGP peer.

When a TCP disconnect is detected, the state falls back to Active. For any other errors, such as an expirationof the hold timer, BGP sends a notification message with the corresponding error code. Then it returns to theIdle state.* OpenConfirm - While in OpenConfirm state, BGP is waiting for a keepalive or notification message. If akeepalive message is received, the state goes to the Established state, and the neighbor negotiation iscomplete. If the system receives an update or keepalive message, it restarts the hold time, assuming that thenegotiated hold time is not zero. If a notification message is received, the state falls back to Idle. The systemsends periodic keepalive messages at the rate set by the keepalive timer. In the case of any TCP disconnect orin response to any stop event, initiated by the system or the administrator, the state returns to Idle. In responseto any other event, the system sends a notification message with an FSM error code and returns to the Idlestate.* Established - Established is the final state in the neighbor negotiation. BGP starts exchangingBeITCertified.comupdate packets with its peers. If it is non-zero, the hold timer is restarted at the receipt of an update orkeepalive message.

QUESTION 28The "show ip bgp" command was issued on a Router as shown below:

Based on the Router2 output, which statement is true?


A. The best path to reach the 192.168.11.0 prefix is via 10.200.200.11.B. The 192.168.11.0 and 192.168.12.0 prefixes were learned via EBGP from the 10.200.200.11 and

10.200.200.12 EBGP neighbors.C. The best path to reach the 192.168.11.0 prefix is via both 10.200.200.11 and 10.200.200.12; BGP will

automatically load balance between the two.D. The best path to reach the 192.168.11.0 prefix is via 10.200.200.12.E. None of the other alternatives apply.


Explanation/Reference:Explanation:The best path to any given destination is noted by the ">" in the IP BGP table. In this case, the best path to192.168.11.0 is via next hop 10.200.200.12 due to the fact that the weight is higher (101) than the path via thealternative next hop. Weight is a Cisco proprietary method for path determination and the weight value is usedabove all other values. Within a router, the path with the highest weight will be preferred.

QUESTION 29While verifying BGP operation on the Company router, you issue the "show ip bgp" command as shown below:

routerR>show ip bgpBGP table version is 1046033, local router ID is 198.32.162.100 Status codes: s suppressed, d damped, hhistory, * valid, > best, i - internal Origin codes: i - IGP, e EGP, ? -incomplete

BeITCertified.comNetwork Next Hop Metric LocPrf Weight Path* > 143.16.0.0 128.214.63.2 0 400 0 200 1* 143.16.0.0 192.208.10.5 0 300 0 300 1* 143.16.0.0 143.16.63.5 0 100 0 200 1* 143.16.0.0 203.250.13.41 0 100 0 500 1

From the information above, which path will the network 143.16.0.0 prefer to take to exit the AS?

A. 128.214.63.2B. 192.208.10.5C. 128.213.63.5D. 203.250.13.41E. All of the above will be used in a round robin fashion.



Explanation:Local preference (LocPref) is a well-known discretionary attribute that provides an indication to routers in theAS about which path is preferred to exit the AS. A path with a higher local preference is more preferred. In thisscenario the following entry has the highest local preference value of 400.Network Next Hop Metric LocPrf Weight Path* > 128.213.0.0 128.214.63.2 0 400 0 200 1

The preferred exit path of the AS is therefore 128.214.63.2, as noted by the">" which refers to the best path forthis destination.

QUESTION 30Refer to the exhibit. Router RTR is attempting to establish BGP neighbor relationships with routers RT1 andRT3. On the basis of the information that is presented in the exhibit, which two statements are true? (Choosetwo.)

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A. RTR has a BGP password set but neighbor 10.0.0.1 does not.B. Neighbor 10.0.0.5 has a BGP password set but RTR does not.C. RTR has a BGP password set but neighbor 10.0.0.5 does not.D. RTR has a BGP password set but neighbor 10.0.0.1 has an incorrect password set.E. Neighbor 10.0.0.1 has a BGP password set but RTR does not.F. RTR has a BGP password set but neighbor 10.0.0.5 has an incorrect password set.

Correct Answer: AFSection: (none)Explanation


Explanation:The above log message means that there is an invalid MD5 password on one neighbor, where the otherneighbor is configured for authentication while the other is not. If both sides were configured and there was apassword mismatch, the error message would indicated "Bad MD5 digest" not "No MD5 digest."

Only one configuration step is required to use BGP password authentication; that step is enabling passwordauthentication on a peer-by-peer basis using the neighbor ip-address password password command.

neighbor {ip-address | peer-group} password [0-7] password-string

QUESTION 31A company has a BGP network and a BGP route of 196.27.125.0/24 that should be propagated to all of thedevices. The route is not now in any of the routing tables. The administrator determines that an access list isthe cause of the problem. The administrator changes the access list to allow this route, but the route still doesnot appear in any of the routing tables. What should be done to propagate this route?

A. Clear the BGP session.B. Change both the inbound and outbound policy related to this route.C. Use the service-policy command to adjust the QOS policy to allow the route to propagate.D. Use the release BGP routing command.


Explanation/Reference:BeITCertified.comExplanation:When configuring BGP, changes made to an existing configuration may not appear immediately. In order toforce BGP to clear its table and reset BGP sessions, use the clear ip bgp * command :Router# clear ip bgp *The asterisk (*) is a wildcard that matches all table entries. Therefore, all BGP routes are lost while theneighbor relationships are reset. This is expedient and very useful in a lab situation, but caution should beexercised when issuing this command on a production router. On an Internet backbone router, it may be moreappropriate to use this command with a specific IP address, as shown in the following:Router# clear ip bgp 192.168.0.0

QUESTION 32Refer to the exhibit. Routers RTA and RTB are running BGP but the session is active. What command needs tobe added to establish the BGP session? "Pass Any Exam. Any Time." - Guaranteed 28Cisco 642-832: Practice Exam

A. ip route 10.10.10.1 255.255.255.255 s0/0ip route 10.10.10.1 255.255.255.255 s0/1

B. network 10.10.10.0C. no synchronizationD. neighbor 10.10.10.1 next-hop-self


Explanation/Reference:BeITCertified.comExplanation:When BGP is running between routers in different autonomous systems, it is called External BGP (EBGP).When BGP is running between routers in the same AS, it is called Internal BGP (IBGP). BGP allows the paththat packets take to be manipulated by the AS, as described in this module. It is important to understand howBGP works to avoid creating problems for your AS as a result of running BGP. A static route can be used toform an adjacency between EBGP neighbors.

QUESTION 33Refer to the exhibit. Router RT3 discovers network 202.176.56.0 via BGP. Which one of these statements istrue?


A. RT1 advertised network 202.176.50.0/24 with a metric of 782.B. RT3 is directly connected to RT1 using subnet 192.168.1.0.C. RT3 has an IGP metric of 782 to reach 192.168.1.1.D. RT3 has a BGP metric of 782 to reach 192.168.1.1.E. RT1 advertised network 202.176.50.0/24 with a metric of 1000.F. RT3 has an IGP metric of 1782 to reach 202.176.56.0/24.


Explanation/Reference:Explanation:BeITCertified.com

QUESTION 34Refer to the exhibit. On the basis of the information in the exhibit, which two statements are true? (Choose two.)


A. When traffic is sent from the ISP to autonomous system 64512, the traffic will be forwarded to SanJose2because of the higher MED value of SanJose2.

B. The serial 0/0/1 interface on the ISP router has been configured with the set metric 50 command.C. The output was generated by entering the show ip bgp command on the SanJose1 router.D. The output was generated by entering the show ip bgp command on the ISP router.E. The serial 0/0/1 interface on the ISP router has been configured with the set metric 75 BeITCertified.com

command.F. When traffic is sent from the ISP to autonomous system 64512, the traffic will be forwarded to SanJose1

because of the lower MED value of SanJose1.

Correct Answer: DFSection: (none)Explanation

Explanation/Reference:Explanation:The "show ip route bgp" command will display any BGP-learned routes that make it into the IP routing table, thecommand "show ip bgp" is required to display the contents of the actual BGP routing table. This output wasseen on ISP because the local router ID is 192.168.100.1 (ISP). Since we know that this output must have beenseen by ISP, we know the serial 0/0/1 interface has been configured with a metric of 75, as this is the metric tothe peer with IP address 192.168.1.2 (the other side of the serial 0/0/1 interface).


QUESTION 35Refer to the exhibit. All routers are configured for BGP. EBGP routes received on router R2 show up in the BGPtable on routers R1 and R3 but not in their IP routing tables. What would cause this?

A. EBGP multihop is not configured on routers R1 and R3.B. Routers R1 and R3 do not receive the same routes via an IGP.C. Synchronization in autonomous system 100 is turned is on.D. The BGP routers in autonomous system 100 are not logically fully-meshed.E. Synchronization in autonomous system 100 is turned is off.

Correct Answer: BCSection: (none)Explanation

Explanation/Reference:Explanation:If your AS passes traffic from another AS to a third AS, BGP should not advertise a route before allBeITCertified.comrouters in your AS learn about the route via IGP. BGP waits until IGP propagates the route within the AS andthen advertises it to external peers. A BGP router with synchronization enabled does not install iBGP learnedroutes into its routing table if it is not able to validate those routes in its IGP. Issue the no synchronizationcommand under router bgp in order to disable synchronization. This prevents BGP from validating iBGP routesin IGP. In this scenario, the routers must learn of the same route via an IGP, or synchronization should beturned off. Since this AS does not appear to be a transit AS, the best solution would be to disablesynchronization.Reference: BGP Case Studies,http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a00800c95bb.shtml#synch

QUESTION 36The network consists of two separate autonomous systems as shown below:


You need to configure Router R2 as a BGP route reflector and Router R1 as the client. Assuming that RouterR3 isn't running BGP, which two of the commands below would you enter on R2 to satisfy your goals? (Selecttwo)

A. neighbor 165.50.12.1 remote-as 65100B. neighbor 165.50.12.2 remote-as 64000C. neighbor 165.50.12.1 route-reflector-clientD. neighbor 165.50.12.2 route reflector-client

Correct Answer: BDSection: (none)Explanation

Explanation/Reference:Explanation:B: RouterR2(config-router)# neighbor 165.50.12.2 remote-as 64000 We configure router R1 (165.50.12.2) as aneighbor in AS 64000.D: RouterR2(config-router)# neighbor 165.50.12.2 route-reflector-client Configures the router R2 as a BGProute reflector and configures the specified neighbor R1 (165.50.12.2) as its client.Incorrect Answers:A: We must specify router R1 as neighbor, not R2 itself (165.50.12.1). Furthermore, we should use the local AS(64000), not the remote AS 65100.BeITCertified.comC: We must specify router R1 as route reflector client, not R2 itself (165.50.12.1).

QUESTION 37The network consists of a series of routers that are all configured for IBGP. Which one of the following IBGPcharacteristics is true?

A. The IBGP routers must always be fully meshed.B. The IBGP routers can be in a different AS.C. The IBGP routers must be directly connected.D. The IBGP routers do not need to be directly connected.E. None of the other alternatives apply are true.



Explanation:The IBGP routers do not have to be directly connected. The remote IBGP peers need only be reachable via aTCP connection. For example, if the network is also running an interior routing protocol such as EIGRP orOSPF, the remote IBGP router could be many hops away, as long as it is reachable via the IGP that is beingused.Incorrect Answers:A: Using route reflectors or confederations a full mesh topology is not necessary.B: The IBGP routers must be placed in the same AS. Peers that are in different autonomous systems are usingEBGP, not IBGP.C: The IBGP routers do not have to be directly connected.

QUESTION 38A BGP router is configured as shown below:

interface ethernet 0ip address 10.10.10.1 255.255.0.0!int serial 0ip address 172.16.1.1 255.255.255.252!router bgp 65001neighbor 192.168.1.1 remote-as 65002

Based on the above configuration, which of the following BGP statements would inject the BeITCertified.com10.10.0.0/16 prefix into the BGP routing table?

A. network 10.0.0.0B. network 10.10.0.0 mask 255.255.0.0C. network 10.10.10.1 mask 255.255.255.255D. network 10.10.10.0 mask 255.255.255.0E. network 10.0.0.0 mask 255.255.0.0


Explanation/Reference:Explanation:The /16 mask is equal to 255.255.0.0, so answer choice B matches the address and the mask. To specify theroute as classless, the mask keyword should be included or the network will be summarized at the networkboundary.


QUESTION 39Router R-1 is configured for BGP routing as shown below:

router bgp 65300network 27.0.0.0neighbor 192.23.1.1 remote-as 65300


From the perspective of router R-1, what kind of router is the router with IP address 192.23.1.1?

A. A peer router running IBGPB. A peer router running EBGPC. A community member running IBGPD. A peer group member running IBGPE. A peer group member running EBGP


Explanation/Reference:Explanation:Both the local and remote router is configured with the same autonomous system number so they are peerrouters running IBGP.

QUESTION 40The BGP routing table consists of the following network routes:

BeITCertified.com

What is the correct command to summarize these prefixes into a single summary prefix of 192.168.12.0/22while also allowing for the advertisement of the more specific prefixes?

A. network 192.168.12.0 mask 255.255.252.0B. network 192.168.12.0 mask 0.0.3.255C. network 192.168.12.0D. aggregate-address 192.168.12.0 255.255.252.0E. aggregate-address 192.168.12.0 255.255.252.0 summary-onlyF. aggregate-address 192.168.12.0 255.255.252.0 as-set



Explanation/Reference:Explanation:

To summarize BGP prefixes into one aggregated route, use the "aggregate-address" command. When usedalone, this will advertise the aggregate route, along with the individual specific routing entries. To advertise onlythe aggregated route, use the "summary-only" keyword, as specified in choice E.

QUESTION 41Router R1 needs to be configured to advertise a specific network. Which of the following commands would youuse if you wanted to advertise the subnet 154.2.1.0 255.255.255.0 to the EBGP neighbors on your subnet?

A. Router (config-router)#network 154.2.1.0B. Router (config-router)#network 164.2.1.0C. Router (config-router)#network-advertise 154.2.1.0D. Router (config-router)#network 154.2.1.0 mask 255.255.255.0E. None of the other alternatives apply


Explanation/Reference:Explanation:The network command is used to specify the networks to be advertised by the Border Gateway Protocol (BGP)and multiprotocol BGP routing processes. Syntax: network network-number [ mask network-mask ] [ route-mapmap-name ] Mask and route-map are optional. If the mask keyword is configured, then an exact match mustBeITCertified.comexist in the routing table.Incorrect Answers:A: If we do not specify the subnet mask then additional networks are allowed to be advertised. The classfulsubnet mask of 154.2.1.0 is 255.255.0.0 - a Class B network.B: This is using the incorrect IP address, as well as a missing subnet mask.C: The network-advertise is an invalid command.

QUESTION 42You are the administrator of a company with BGP connections to multiple ISP's. How could you configure BGPto make it favor one particular ISP for outbound traffic?

A. Configure weightB. Enable route reflector


C. Create a distribute listD. Enable the Longer Autonomous System path option.E. All of the above.


Explanation/Reference:Explanation:If the router learns about more than one route to the same destination, the route with the highest weight will bepreferred. Weight is a Cisco BGP parameter that is local to the router. When terminating multiple ISPconnections into the same router, weight can be used to affect which path is chosen for outbound traffic.Incorrect Answers:B: A route reflector cannot be used to influence outbound traffic. A route reflector modifies the BGP splithorizon rule by allowing the router configured as the route reflector to propagate routes learned by IBGP toother IBGP peers. This saves on the number of BGP TCP sessions that must be maintained, and also reducesthe BGP routing traffic.

C: Distribute lists restrict the routing information that the router learns or advertises. By itself a distribute listcannot make routes from one ISP be preferred to routers from another ISP.D: This choice describes ASD path pre-pending, which would be used to influence the path that incoming traffictakes, not outgoing.

QUESTION 43An ISP is running a large IBPG network with 25 routers. The full mesh topology that is currently in place isinefficiently using up bandwidth from all of the BGP traffic. What can the administrator configure to reduce thenumber of BGP neighbor relationships within the AS?

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A. Route reflectorsB. Route mapsC. Route redistributionD. Peer groupsE. Aggregate addresses


Explanation/Reference:Explanation:In general, all IBGP peers must be configured to be fully meshed. If they are not, then all of the IBGP routerswill not have the updated information from the external BGP routers. There are two ways to overcome thescalability issues of a full IBGP mesh: route reflectors and confederations. With route reflectors, internal BGProuters peer only with the route reflector, and then the route reflectors connect with each other. This canconsiderably reduce the number of IBGP sessions. Another solution to the scalability problem of IBGP is theuse of confederations. With confederations, the AS is broken up into smaller, more manageable subautonomous systems.


QUESTION 44What are the two reasons for the appearance of 0.0.0.0 as the next hop for a network when using the "show ipbgp" command? (Choose two)

A. The network was originated via redistribution of an interior gateway protocol into BGP.B. The network was defined by a static route.C. The network was learned via IBGP.D. The network was learned via EBGP.E. The network was originated via a network or aggregate command.

Correct Answer: AESection: (none)Explanation

Explanation/Reference:Explanation:From BGP FAQ on www.cisco.com :

Q. What does a next hop of 0.0.0.0 mean in the show ip bgp command output?

A. A network in the BGP table with a next hop address of 0.0.0.0 means that the network is locally originatedvia redistribution of Interior Gateway Protocol (IGP) into BGP, or via a network or aggregate command in the

BGP configuration.

Reference:http://www.cisco.com/en/US/tech/tk365/technologies_q_and_a_item09186a00800949e8.shtml#tw o

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QUESTION 45Refer to the exhibit diagram and configuration. RTB is summarizing its networks from AS 64100 with theaggregate-address command. However, the show ip route command on RTA reveals the RTB individualnetworks as well as its summary route. Which option would ensure that only the summary route would appearin the routing table of RTA?


A. Add a static route with a prefix of 192.168.24.0 255.255.252.0 pointing to the null0 interface.B. Create a route map permitting only the summary address.C. Delete the four network statements and leave only the aggregate-address statement in the BGP

configuration.D. Add the keyword summary-only to the aggregate-address command.


Explanation/Reference:Explanation:The aggregate-address <address> <netmask> command advertises the summary address as well astheadvertisement of the more specific routes.

The purpose of aggregate-address <network> <netmask> summary-only command is to suppress the

advertisement of more specific routes.BeITCertified.com

QUESTION 46Refer to the exhibit. BGP has been configured on the routers in the network. However, the IBGP peers inautonomous system 65200 have not converged. In addition, this console message was generated on router R2:

*Mar 1 03:09:07.729: %TCP-6-BADAUTH No MD5 digest from 10.10.23.2(179) to 10.10.23.3(11002)

On the basis of the information that is provided, what is the cause of the problem?


A. OSPF must be configured with the same MD5 authentication.B. BGP authentication can be used on iBGP peers when the connection is configured between the loopback

interfaces.C. BGP authentication can be used on eBGP peers only.D. The password that is used for BGP authentication on both BGP peers in autonomous system 65200 must

be the same.


Explanation/Reference:Explanation:The above log message is relating the invalid MD5 password on neighbor. Both peers need to use the samepassword for MD5 authentication.

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QUESTION 47Refer to the exhibit. Which two statements are correct? (Choose two.)

A. All the routes were redistributed into BGP from an IGP.B. All the routes were originated by BGP with the network command.C. All six routes will be installed in the routing table.


D. Four routes will be installed in the routing table.E. Two routes will be installed in the routing table.


Explanation/Reference:Explanation:Because the AS paths shown all end with a ? we know that all of the routes had beed redistributed into BGP.The four best paths, as noted with the > sign, will all be inserted into the routing table.

Section 4: Troubleshoot routing redistribution solution (5 Questions)

QUESTION 48During a redistribution of routes from OSPF into EIGRP, the administrator notices that none of the OSPF routesare showing up in EIGRP. What are two possible causes? (Choose two.)

A. Incorrect distribute lists have been configuredB. Missing ip classless commandC. CEF not enabledD. No default metric configured for EIGRP


Explanation/Reference:BeITCertified.comExplanation:Possible reasons for OSPF routes not showing up include the use of distribute lists to control routing and nometric is configured either with the redistribute command or with default-metric. Remember while redistributinginto RIP or EIGRP, you should provide the metric. Here are the default seed metrics for various protocols:

RIP : InfinityEIGRP : InfinityOSPF : 20IS-IS: 0

QUESTION 49"Pass Any Exam. Any Time." - Guaranteed 41Cisco 642-832: Practice Exam

Refer to the exhibit and the partial configuration on router R2. On router R4 all RIP routes are redistributed intothe OSPF domain. A second redistribution is configured on router R2 using a route map. Based on theconfiguration on router R2, which EIGRP external routes will be present in the routing table of R1? Select thebest response.

A. There will be no EIGRP external routes in the routing table of R1.B. The routes originating from the RIP routing domain.C. Only routes originating in the OSPF routing domain.

BeITCertified.comD. All routes originating from RIP and OSPF routing domains.E. None of the other alternatives apply.


Explanation/Reference:Explanation:The route-map command is used to configure policy routing, which is often a complicated task. A route map isdefined using the syntax shown in the figure.Syntax:RouterA(Config)#route-map map-tag [permit | deny ] <Sequence Number> RouterA(Config-map-router)#The map-tag is the name, or ID, of the route map. This map-tag can be set to something easily recognizablename. The route-map command changes the mode on the router to the route-map configuration mode, fromthere conditions can be configured for the route map. Route maps operate similar to access lists, by examiningone line at a time and when a match is found, action is taken. Route maps are different from numbered accesslists because they can be modified without changing the entire list. Each route map statement is given anumber. If a "Pass Any Exam. Any Time." - Guaranteed 42Cisco 642-832: Practice Exam

sequence number is not specified, the first route map condition will automatically be numbered as ten (10). Thesecond condition will automatically be numbered as 20, and so on. The optional sequence number can be usedto indicate the position that a new route map is to have in the list of route maps already configured with thesame name.In this exhibit an access-list is created to deny from 100.10.0.0 and 200.10.10.0 (RIP Domain) and that is calledby route-map ABC. While redistributing OSPF routes into EIGRP the RED rout-map is used; and it deniesadvertising the RIP domain network into EIGRP.

QUESTION 50Refer to the exhibit. The routing protocols EIGRP and OSPF have been configured as indicated in the exhibit.Given the partial configuration of router R2, which network will be present in the routing table of R4?

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A. Network BB. Network A and Network BC. Network A

D. neither Network A nor Network B"Pass Any Exam. Any Time." - Guaranteed 43Cisco 642-832: Practice Exam


Explanation/Reference:Explanation:In this exhibit the OSPF domain is redistributed into the EIGRP 100 domain so Network B will present intoRouter R4. However, the Network A network will not be seen on router R4 (The bottom router which isimproperly labeled Network B) because EIGRP 50 was not redistributed into EIGRP 100.

QUESTION 51Refer to the network shown below:

R1 and R2 belong to the RIP routing domain that includes the networks 10.20.0.0/16 and 10.21.0.0/16. R3 andR4 are performing two-way route redistribution between OSPF and RIP. A network administrator hasdiscovered that R2 is receiving OSPF routes for the networks 10.20.0.0/16 and 10.21.0.0/16 and a routing loophas occurred. Which action will correct this problem?

A. Set the OSPF default metric to 20.B. Apply an inbound ACL to the R2 serial interface.

BeITCertified.comC. Configure distribute-lists on R3 and R4.D. Change the RIP administrative distance on R3 to 110.E. Change the OSPF administrative distance on R3 to 110.F. None of the other alternatives apply


Explanation/Reference:Explanation:Use the distribute-list command to pick and choose which routing updates a router will send or receive. Byreferencing an access list, the distribute-list creates a route filter. This is a set of rules that precisely controlswhat routes a router will send or receive in a routing update. This command is available for all IP routingprotocols and can be applied to either inbound or outbound routing updates. When applied to inbound updates,the syntax for configuring a route filter is as follows:

Router(config-router)# distribute-list access-list-number in [ interface-name ] When applied to outboundupdates, the syntax can be more complicated as shown in the following:


Router(config-router)# distribute-list access-list-number out [ interface-name | routing-process | as-number ]The routing-process and as-number options are invoked when exchanging routes between different routingprotocols.

QUESTION 52RIP and OSPF are configured on the routers as shown in the exhibit. R2 is configured with a two- wayredistribution between RIP and OSPF domains. All routers can ping each other, but R1 cannot see any of theOSPF routes in its routing table. What could the problem be?

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A. OSPF and RIP use the same major network 172.16.0.0. Therefore, the keyword subnets is not required toredistribute protocols into OSPF.

B. Because OSPF has a longer mask for the same major network than RIP and because RIP version 1 isbeing used, none of the routes learned from OSPF will be advertised into RIP.

C. The metric for the OSPF routes that are redistributed into RIP is too low, a fact that prevents OSPF routesfrom being advertised into RIP.

D. The process of redistribution of RIP into OSPF does not require any metric conversion, so there is no needto define the metric using the default-metric command during the redistribution.

Correct Answer: BSection: (none)

Explanation

Explanation/Reference:Explanation:The subnets keyword tells OSPF to redistribute all subnet routes. Without the subnets keyword, only networksthat are not subnetted are redistributed by OSPF.Example:Router A(config)# router ospf 109 Router A(config-router)# redistribute rip subnets Router


A(config-router)# network 130.10.62.0 0.0.0.255 area 0 Router A(config-router)# network 130.10.63.0 0.0.0.255area 0

Section 5: Troubleshoot a DHCP client and server solution (13 Questions)

QUESTION 53What is the purpose of configuring router R1 with the "IP Helper address" command?

A. IP Helper is used to direct BOOTP clients to a BOOTP server.B. IP Helper is used to prevent the router form forwarding IP broadcasts.C. IP Helper is used to allow IPX clients to communicate with IP-based servers.D. IP Helper is used to accommodate compatibility routers using different IP routing protocols.E. None of the other alternatives apply


Explanation/Reference:Explanation:The ip helper-address command is used to have the Cisco IOS software forward User Datagram Protocol(UDP) broadcasts, including BOOTP, received on an interface. DHCP protocol information is carried inside ofBOOTP packets. To enable BOOTP broadcast forwarding for a set of clients, configure a helper address on therouter interface closest to the client. The helper address should specify the address of the DHCP server. Note:A DHCP server can be considered to be a BOOTP server, even though a DHCP server is more advanced.BeITCertified.comIncorrect Answers:B: Combined with the ip forward-protocol global configuration command, the ip helper-address commandallows you to control which broadcast packets and which protocols are forwarded. However, the main purposeof the IP helper feature is not to prevent the router from forwarding IP broadcasts.C: IP helper does not use IPX.D: This is false.

QUESTION 54When you execute the "ip helper-address" command on a router, which three UDP ports get enabledautomatically by default? (Select three)

A. 53 (DNS)"Pass Any Exam. Any Time." - Guaranteed 46Cisco 642-832: Practice Exam

B. 69 (TFTP)C. 515 (LPR)D. 161 (SNMP)E. 49 (TACACS)

Correct Answer: ABESection: (none)Explanation

Explanation/Reference:Explanation:To forward the BootP/DHCP request from the client to the DHCP server, the ip helper-address interfacecommand is used. The IP helper-address can be configured to forward any UDP broadcast based on UDP portnumber. By default, the IP helper-address will forward the following UDP broadcasts: DNS (port 53), timeservice (port 37) Trivial File Transfer Protocol (TFTP) (port69) Terminal Access Control Access Control System (TACACS) service (port 49) NetBIOS name server (port137) NetBIOS datagram server (port 138) Boot Protocol (DHCP/BootP) client and server datagrams (ports 67and 68) IEN-116 name service (port 42) Reference: Understanding and Troubleshooting DHCP in CatalystSwitch or Enterprise Networks http://www.cisco.com/warp/public/473/100.html

QUESTION 55Refer to the exhibit. Router RTA has been configured as a DHCP server. The two debug commands willgenerate output on RTA when Host A requests an IP address. Which set of DHCPD debug messages is in thecorrect sequence?

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A. DHCPD: Sending DHCPOFFER to clientDHCPD: DHCPDISCOVER received from clientDHCPD: DHCPREQUEST received from clientDHCPD: Sending DHCPACK to client

B. DHCPD: DHCPDISCOVER received from clientDHCPD: DHCPREQUEST received from clientDHCPD: Sending DHCPOFFER to client

DHCPD: Sending DHCPACK to clientC. DHCPD: DHCPDISCOVER received from client

DHCPD: Sending DHCPOFFER to clientDHCPD: DHCPREQUEST received from clientDHCPD: Sending DHCPACK to client

D. DHCPD: DHCPREQUEST received from clientDHCPD: Sending DHCPOFFER to clientDHCPD: DHCPDISCOVER received from clientDHCPD: Sending DHCPACK to client

E. DHCPD: Sending DHCPACK to clientDHCPD: DHCPDISCOVER received from clientDHCPD: Sending DHCPOFFER to clientDHCPD: DHCPREQUEST received from client

F. DHCPD: DHCPDISCOVER received from clientDHCPD: Sending DHCPACK to clientDHCPD: Sending DHCPOFFER to clientDHCPD: DHCPREQUEST received from client


Explanation/Reference:BeITCertified.comExplanation:The following example shows a combination of DHCP server events and decoded receptions andtransmissions:Router# debug ip dhcp server eventsRouter# debug ip dhcp server packets

DHCPD:DHCPDISCOVER received from client 0b07.1134.a029 through relay 10.1.0.253. DHCPD:assigned IPaddress 10.1.0.3 to client 0b07.1134.a029. DHCPD:Sending DHCPOFFER to client 0b07.1134.a029 (10.1.0.3).DHCPD:unicasting BOOTREPLY for client 0b07.1134.a029 to relay 10.1.0.253. DHCPD:DHCPREQUESTreceived from client 0b07.1134.a029. DHCPD:Sending DHCPACK to client 0b07.1134.a029 (10.1.0.3).DHCPD:unicasting BOOTREPLY for client 0b07.1134.a029 to relay 10.1.0.253.DHCPD:checking for expired leases.

Note that for this question, the correct order of events are highlighted above.


Reference:http://www.cisco.com/en/US/docs/ios/debug/command/reference/db_h1.html#wp1020307

QUESTION 56Refer to the exhibit. Router RTA has been configured as a DHCP server for router RTC. On the basis of theinformation that is provided, which statement about DHCP is true?

A. The VLAN1-POOL argument must be issued for the Fa0/1 interface on router RTA.BeITCertified.com

B. Router RTA must be configured with the default-router 192.168.3.2 DHCP command.C. The ip address dhcp interface configuration command must be issued for the Fa0/1 interface of router RTA.D. The ip helper-address 192.168.1.2 interface configuration command must be issued for the Fa0/1 interface

on router RTA.E. Router RTC must be configured with the ip address dhcp global configuration command.F. The lease 2 0 0 DHCP configuration command would change the default DHCP lease time to 48 hours on

router RTA.

Correct Answer: FSection: (none)Explanation

Explanation/Reference:Explanation:Configuring the Address Lease Time:By default, each IP address assigned by a DHCP server comes with a one-day lease, which is the amount oftime that the address is valid. To change the lease value for an IP address, use the following command inDHCP pool configuration mode:


Reference:http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/120t/120t1/easyip2.ht m#22915

QUESTION 57Refer to the exhibit. Which statement is true about the information that is given?

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A. Router R2 will distribute incorrect default router option information to DHCP clients because it is importingthis information from R1.

B. As configured, router R2 will retrieve domain name and other option information from R1.C. For the import all command to work on router R2, its Fa0/1 interface must be configured as a DHCP client.D. The DHCP clients of router R2 will receive the same option information that the clients of R1 receive.



Explanation/Reference:Explanation:DHCP Server Options Import and Autoconfiguration Example:The following example shows a remote and central server configured to support DHCP options import andautoconfiguration. The central server is configured to automatically update DHCP options, such as DNS andWINs addresses, within the DHCP pools. In response to a DHCP request from a local client behind CPEequipment, the remote server can request or "import" these option parameters from the centralized server. Seebelow for a diagram of the network topology.

Central Router!do not assign this range to DHCP clientsip dhcp-excluded address 10.0.0.1 10.0.0.5!ip dhcp pool central! Specifies network number and mask for DHCP clientsBeITCertified.comnetwork 10.0.0.0 255.255.255.0! Specifes the domain name for the clientdomain-name central! Specifies DNS server that will respond to DHCP clients when they need to correlate host ! name to ip addressdns-server 10.0.0.2!Specifies the NETBIOS WINS servernetbios-name-server 10.0.0.2!interface FastEthernet0/0ip address 10.0.0.1 255.255.255.0duplex autospeed auto

Remote Router!

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Documents

Testking Cisco 642-832 formatted - GRATIS EXAM...2012/01/06 · Although the loopback interface is using a /24 subnet mask, EIGRP summarizes at network boundaries by default so the