Network+ N10-005 NotesTable of Contents1.0: NETWORKING CONCEPTS61.1 Compare the layers of the OSI and TCP/IP models6OSI Model (Open Systems Interconnection Reference Model)6TCP/IP Model81.2 Classify how applications, devices, and protocols relate to the OSI model layers81.3 Explain the purpose and properties of IP addressing9Basic Binary Math9Subnetting9Classes of Addresses10IPv4 vs. IPv611MAC Addresses12APIPA (Automatic Private IP Addressing)12Multicast vs. Unicast vs. Broadcast121.4 Explain the purpose and properties of routing and switching13EIGRP (Enhanced Interior Gateway Routing Protocol)13OSPF (Open Shortest Path First)14RIP (Routing Information Protocol)14IS-IS14Link State vs. Distance-Vector vs. Hybrid15Static and Dynamic Routing15Routing Metrics16Next Hop16Spanning Tree Protocol (STP)17VLANs (Virtual LANs)17Port Mirroring18Broadcast Domain vs. Collision Domain18IGP vs. EGP19Routing Tables20Convergence20Types of Switches201.5 Identify common TCP and UDP default ports211.6 Explain the function of common networking protocols22TCP/IP Protocol Suite221.7 Summarize DNS concepts and its components251.8 Given a scenario, implement the following network troubleshooting methodology271.9 Identify virtual network components28Virtual Machine Manager (VMM)28Virtual Servers28Virtual Desktops28Server Consolidation29Virtual Switches29Network as a Service (NaaS)29Onsite vs. Offsite Virtualization29Virtual PBX302.0: NETWORK INSTALLATION & CONFIGURATION312.1 Given a scenario, install and configure routers and switches31Types of Routers31Routing Tables31NAT (Network Address Translation)32VLAN32Managed vs. Unmanaged Switches33Interface Configurations33PoE (Power Over Ethernet)33Traffic Filtering34Diagnostics34VTP Configuration (VLAN Trunking Protocol Configuration)34QoS (Quality of Service)34Port Mirroring352.2 Given a scenario, install and configure a wireless network35Wireless LANs35WAP Placement36Antenna Types37Interference37Frequencies and Channels37Wireless Standards38SSID Management402.3 Explain the purpose and properties of DHCP40DHCP40Reservations41Scopes41Leases41Options422.4 Given a scenario, troubleshoot common wireless problems422.5 Given a scenario, troubleshoot common router and switch problems43Switching Loops43Bad Cables/Improper Cable Types43Port Configuration44VLAN Assignment44Mismatched MTU/MUT Black Hole44Power Failure45Bad/Missing Routes45Bad Fiber Modules46Wrong Subnet Mask and Gateway46Duplicate IP Address46Wrong DNS462.6 Given a set of requirements, plan and implement a basic SOHO network47List of Requirements47SOHO Cabling47Device Types47Environmental Limitations47Equipment Limitations47Compatibility Requirements473.0 NETWORK MEDIA AND TOPOLOGIES483.1 Categorize standard media types and associated properties48Fiber48Copper49Cable Categories50Straight-Through cables50Crossover cables50Plenum Cables51Media Converters51Media Distance and Speed Limitations51Broadband over Powerline (BPL)523.2 Categorize standard connector types based on network media52Fiber52Copper533.3 Compare and contrast different wireless standards543.4 Categorize WAN technology types and properties54T-Carrier System54Synchronous Optical Networking55Satellite55ISDN (Integrated Services Digital Network)56DSL56Leased Lines56Cable56Dialup57Cellular57OCx Standard58DWDM (Dense Wavelength-Division Multiplexing)58PON (Passive Optical Network)58Frame Relay59ATM (Asynchronous Transfer Mode)59Properties593.5 Describe different network topologies61MPLS (Multiprotocol Label Switching)61Point-to-Point61Point-to-Multipoint61Ring, Star, Mesh, Bus and Hybrid Topologies61Client-Server62Peer-to-Peer623.6 Given a scenario, troubleshoot common physical connectivity problems62Bad Connectors and Wiring62Opens and Shorts63Split Cables63dB Loss63TXRX Reversed64Cable Placement64EMI/Interference64Crosstalk (XT)643.7 Compare and contrast different LAN technologies65Ethernet Frames65Types of LAN Technologies65CSMA/CD66CSMA/CA67Bonding/Link Aggregation673.8 Identify components of wiring distribution67Distribution frames67MDF (Main Distribution Frame)68IDF (Intermediate Distribution Frame)68Vertical / Horizontal Cross-Connects68Demarc68Smartjack68CSU/DSU (Channel Service Unit / Data Service Unit)694.0 NETWORK MANAGEMENT704.1 Explain the purpose of features of various network appliances70Load Balancer70Proxy Servers70Content Filter70VPN Concentrator714.2 Given a scenario, use appropriate hardware tools to troubleshoot connectivity issues71Crimpers71Linemans Handset71Toner Probe72Punch Down Tools72Protocol Analyzer72Loopback Plugs72TDR/OTDR72Multimeters73Environmental Monitors734.3 Given a scenario, use appropriate software tools to troubleshoot connectivity issues73Using Protocol Analyzers73Throughput Testers73Ping74Tracert74Nslookup/Dig74Ipconfig/Ifconfig74ARP (Address Resolution Protocol)75Nbtstat75Netstat75Route754.4 Given a scenario, use the appropriate network monitoring resource to analyze traffic75SNMP (Simple Network Management Protocol)75Syslog76Traffic Analysis764.5 Describe the purpose of configuration management documentation77Wiring Schemes77Network Maps77Documentation77Cable Management77Asset Management78Baselines78Change Management784.6 Explain different methods and rationales for network performance optimization78Methods78Reasons795.0: NETWORK SECURITY805.1 Given a scenario, implement appropriate wireless security measures80Encryption Protocols80MAC Address Filtering80Signal Strength81Device Placement815.2 Explain the methods of network access security81ACL (Access Control Lists)81Tunneling and Encryption81Remote Access835.3 Explain methods of user authentication83Hashing83PKI (Public Key Infrastructure)83Kerberos84AAA (Authentication, Authorization, and Accounting)85Network Access Control85CHAP86EAP (Extensible Authentication Protocol)86Multi factor Authentication86Singe Sign-On (SSO)875.4 Explain common threats, vulnerabilities, and mitigation techniques87Wireless87Attacks88Mitigation Techniques905.5 Given a scenario, install and configure a basic firewall91Types of Firewalls91Stateful Inspection vs. Packet Filtering91Firewall Rules91PAT (Port Address Translation)91DMZ (Demilitarized Zone)925.6 Categorize different types of network security appliances and methods92IDS and IPS92Vulnerability Scanners92Methods92

1.0: NETWORKING CONCEPTS

1.1 Compare the layers of the OSI and TCP/IP modelsOSI Model (Open Systems Interconnection Reference Model) A vender-neutral basis for open system networks developed by ISO Acts as a guide for network protocol, not a be-all-end-all Developed to standardize networks, even before protocols were invented There are unique protocols at every layer The higher layers request services from other layers Application Support Layers: 7 (Application), 6 (Presentation), and 5 (Session) Network Support Layers: 4 (Transport), 3 (Network), 2 (Data Link), and 1 (Physical) All network technicians use this model Trick to remember layers from 7 to 1: All People Seem To Need Data ProcessingOSI Data Encapsulation

Layer 7: Application Layer The layer that we see on the screen1. Converts information suitable for transmission

This is the only layer that users interact with directly HTTP, FTP, DNS, SNMP, SMTP and POP3 are protocols associated with Layer 7 All operating systems have an API (Application Programming Interface) that is used by programmers to make their programs network aware Layer 6: Presentation Layer Responsible for putting information into a format readable by the OS Converts the representation of one system to that of another system Performs character encoding, application encryption, decryption, and data compression Often combined with Layer 7 SSL/TLS and ASN.1 reside at this layer Layer 5: Session Layer Communication management between devices. Establishes connections between devices and applications, maintaining the connection and termination/re-establishing them when required Where half-duplex or full-duplex and configured Synchronizes data transfer between devices with different transmission rates Sockets, control protocols and tunneling protocols like RADIUS and TACACS+ exist here Layer 4: Transport Layer2. Data is converted into segments

Sequences packets so that, upon arrival, they can be reassembled The post office layer Responsible for transporting information, end-to-end data transmission, and managing the connections between layers 5 and 3 TCP and UDP reside here Layer 3: Network Layer3. Segments are converted into packets

The routing layer Protocols for reliability, establishing and maintaining connections, and routing live here IP, IGMP, ICMP, ARP, and RIP Also responsible for IP Fragmentation, the splitting of one frame into several different frames/fragments A fragment contains:1. DLC Header2. IP Header3. TCP Header4. TCP Data Everything below the IP Header will be split up and the IP Header and DLC Header will be duplicated Fragments are always in multiples of 8 because the number of fragmentation offset bits in the IP header Packets at this layer are encapsulated into a frame Layer 2: Data Link Layer4. Packets are converted into frames

The switching layer Transfers data between adjacent network nodes without errors The basic network language and foundation for communication Contains Data Link Control (DLC) protocols MAC address on Ethernet Two sublayers: LLC (Logical Link Control) Encapsulates protocols in upper layers so multiple upper layer protocols can share the same media Includes PPP, SLIP, SONET, and Frame Relay MAC (Media Access Control) Defines how packets are transferred onto media Includes the CSMA/CD contention scheme Attaches MAC addresses to frames Frames at this layer can be 1500 bytes of data each Layer 1: Physical Layer5. Frames are converted into bits

Signaling, cabling, connectors You have a physical layer problem Answer: Fix cabling, punch-downs, etc. Ethernet, Fast Ethernet, FDDI, and ATM/Token Ring exist at this layerTCP/IP Model Commonly called the Internet Protocol (IP) suite or model Similar to the OSI model, but more simple with 4 layers Built around the idea of TCP/IP Designed with protocols in mind and to support Internet related tasks PDU (Protocol Data Units) Units of transmission in a network Also known as data, frames, packets, and bits Peer-to-peer communication occurs at the Application and Transport layers1. Link Layer (OSI 1 and 2)TCP/IP Encapsulation

Also called the Network Interface Layer Provides services to send and receive data packets 1. Information is assembled into frames

Moves data frames between adjacent nodes Handles ARP (OSI Layer 2) protocol Responsible for finding (encodes and transmits) the MAC address of a system The first thing that has to happen before a system can communicate 2. Frames go into an IP packet

2. Internet Layer (OSI 3) Transfers data from a source to a destination network Handles IPv4, IPv6, ICMP, and IGMP protocols Packages data into datagrams3. Transport Layer (OSI 4)3. TCP Segments/UDP datagrams

Provides connection establishment and communication services Handles communication between hosts Defines protocols for end-to-end transfer of data along with error and flow controls Uses TCP and UDP protocols4. Applications Layer (OSI 5, 6, 7) Encodes data, controls sessions, and defines socket services over TCP/IP4. Data starts and ends here

Handles communication between processes Contains all other protocols we use For example: FTP, BOOTP, TFTP, DNS, HTTPS, HTTP, IMAP, Telnet, SMTP, SNMP, etc.

1.2 Classify how applications, devices, and protocols relate to the OSI model layers SSL/TLS does not allow external applications to execute. Encryption devices use HSM (Hardware Security Modules), a basic cryptographic device

Layer 1Layer 2Layer 3Layer 4Layer 5Layer 6Layer 7

CablesNICsHubsFramesMAC-addressEUI-48/64SwitchesIP-addressesRoutersPacketsTCP-segmentsUDP-datagramsControl and tunnelingprotocolsEncryption devices (SSL/TLS)Decrypted information on screen

Protocol Binding is the process of assigning a protocol to NIC 1.3 Explain the purpose and properties of IP addressingBasic Binary Math A bit is 0 or 1 8 bits = 1 byte Also referred to an octet A binary-to-decimal conversion chart is good way to calculate a binary numberPlaceholder:1286432168421

Binary #:10000010

Value = 130:128 +0 +0 +0 +0 +0 +2 +0

So 11111111 = 255 Anywhere where there is a 0 in a subnet mask means is part of the host IDSubnetting A subnet mask is used to identify the host ID, subnet ID, and network ID of an IPv4 address The formula 2x 2 is used to determine the number of host addresses A computer uses a subnet mask to determine if the sending address is local to the network or located in a different network. If the subnet masks match, the destination is local Anywhere a 255 exists in an address is the mask, and the client addresses are just zeros There are 256 possible addresses per octet Only 254 possible clients/hosts because the subnet address and broadcast address are subtracted How to calculate subnet address and broadcast address:Given IP Address is 192.168.1.165:With subnet mask of 255.255.255.0:11000000.10101000.00000001.0000000011111111.11111111.11111111.00000000

Perform bitwise AND:11000000.10101000.00000001.00000000

Subnet Address: 192 .168 .1 .0

Change zeros to 1s in last octet:11000000.10101000.00000001.11111111

Broadcast Address: 192 .168 .1 .255

So thus, you figure out the subnet address by converting the IP address and subnet mask to binary and then using something called a bitwise AND to write out a new address in which you place a 1 where ever there is a 1 in the same place in both IP address and subnet mask. Then the broadcast address is obtained converting the subnet address to binary and changing an octet with all zeros to all ones and then reconverting the binary to decimal. Common CIDR notations are /8, /16, /24, /32, or multiples of 8. However, we are not limited to this To modify the subnet, keep adding 1s to the remaining zeros in the subnet mask and increment each CIDR notation by one each time you do that This can leave subnet masks looking like 255.255.255.194 Afterwards, 2^x where x = the amount of zeros that exist in the subnet mask after subnetting is equal to the amount of available hosts (0 - y) Supernetting is to aggregate multiple contiguous IP addresses into a larger address spaceClasses of Addresses Every device needs a unique address Every device needs a subnet mask Every device needs to go through a default gateway (router) The IP address isnt really a single address, but a combination of a network ID and a host ID Classful Subnetting Not used since 1993 Class A: 1.0.0.0 127.255.255.255 (excluding loopback address 127.0.0.1) 255.0.0.0 subnet 1 - 126 leading bit address 128 possible networks Class B: 128.0.0.0 191.255.255.255 255.255.0.0 subnet 128 - 191 leading bit address 16,384 possible networks Class C: 192.0.0.0 223.255.255.255 255.255.255.0 subnet 192 - 223 leading bit addresses 2,097,152 possible networks Class D: 224.0.0.0 239.255.255.255 Multicast servers take on these for all members in a multicast session A router must be configured to handle Class D multicast sessions Class E: 240.0.0.0 255.255.255.255 These addresses are reserved for research Public addresses vs. private addresses RFC 1918 is the standard allowing private addresses Private addresses can be used more than once because they can only be used internally (unregistered) For example: 192.168.0.1 is the IP address for millions of home users When designating private addresses: Class A: 10.0.0.0 - 10.255.255.255 (10.0.0.0/8) Default subnet mask: 255.0.0.0 Single Class A Largest CIDR block = 10.0.0/8 Host ID is 24 bits Class B: 172.16.0.0 - 172.31.255.255 (172.16.0.0/12) Default subnet mask: 255.240.0.0 16 contiguous Class Bs Largest CIDR block = 172.16.0.0/12, Host ID is 20 bits Class C: 192.168.0.0 - 196.168.255.255 (192.168.0.0/16) Default subnet mask: 255.255.0.0 256 contiguous Class Cs Largest CIDR block = 192.168.0.0/16 Host ID is 16 bits Classless Interdomain Routing (CIDR) Useful for further dividing subnets beyond their preconfigured Class A, B, or C standards to make more efficient use of allocated subnets and to perhaps have more control over the exact amount of hosts you need in a network without wasting a ton of IP addresses in the process. Bits are borrowed from the host address for an extended subnet mask VLSM (Variable Length Subnet Masking) is used in this process of creating a custom subnet mask For example: 192.168.1.1/24 is the CIDR notation for really saying that your IP address is 192.168.1.1 and your subnet mask is 255.255.255.0 because the three octets of 255 equal 24-bits (8x3=24), so thus you can just say 192.168.1.1 to mean the same thing. So to further divide beyond the preconfigured subnets of Class A, you will use the IP address of 10.1.0.1/26. This really means you have an IP address of 10.1.0.1 with a corresponding subnet mask of 255.255.255.192. The 26 means that, starting from the left, there are 26 bits that make up the network ID and the remaining 6 bits make up the host ID. This means that the first three octets of 255 were used (8x3=24) along with two additional bits from the last octet are part of the network ID. The octet of 192 in the subnet mask comes from the fact that the two additional bits taken from the last octet of the IP address have the binary definitions of 128 and 64 respectively. 128 + 64 = 192, thus forming the last octet.IPv4 vs. IPv6 IPv4 OSI layer 3 address Series of 4 octets/32-bits IPv6 OSI layer 3 address 128-bits long, four 16-bit groups separated by colons instead of dots Hexadecimal Two or more groups of zeros are abbreviated with a double colon :: This can happen only once per address Leading zeros are optional, can be removed up to the fourth zero in a group DNS becomes very important due to the complexity of the IPv6 compared to the IPv4 IPv6 Multicast addresses FF02::1 = All nodes FF02::2 = All routers FF02::1:FFXX:XXXX = Solicited-node address Subnet masks are simple: just append the CIDR-like /64 at the end of the address Subnet masks in IPv6 cannot be larger than 64-bits Every computer will have two IPv6 addresses: Link-local: FE80::/64 APIPA-like, only can communicate to the local network with this address Global-address: Always starts with the number 2 Allows you to communicate with the Internet To get a global address, the router gives the client a prefix and the client attaches its EUI-64 address to the end of it IPv6 can only do unicast, multicast, or anycast Anycast: Used by DNS servers for multiple servers around the world to act as one, sharing one IP address IPv6 Tunnels Useful for using IPv6 in networks that do not yet support it Types: 6to4 6in4 (NAT traversal) Teredo (NAT traversal) Built into Windows ISATAP Appends an IPv4 address on a IPv6 prefixMAC Addresses MAC stands for Media Access Control OSI layer 2 The physical address of the network adapter card assigned by the manufacturer Referred to as an Extended Unique Identifier (EUI) Trademarked by IEEE as EUI-48 and EUI-64 Can be locally assigned, but this is not common EUI-48 The traditional Ethernet MAC address Six bytes, usually represented in hexadecimal First three bytes are assigned as the OUI (Organizationally Unique Identifier) Last three bytes are usually assigned sequentially to prevent duplicates Dell_6f:06:f2, [00:21:70]:[6f:06:f2] and 00-21-70-6f-06-f2 are all equivalent

LAN Identifier/Device IDOUI/Block ID

EUI-64 Used in newer technologies Used by FireWire and IPv6 link-local auto configuration Eight bytes in hexadecimal First three bytes are the OUI Last five bytes are also assigned sequentially and look the same as EUI-48, just longer Useful for IPv6 hosts Converting to EUI-64 from EUI-48 Split the EUI-48 address into two pieces, 24 bits each Insert FFFE in the middle of the EUI-48 address The 7th bit in the OUI is set to 1 for locally created addresses and set to 0 for globally unique addresses After this 7th bit in the OUI is set, you end up with the EUI-64 addressAPIPA (Automatic Private IP Addressing) A link-local address Not routable: It can be used on a local subnet, but is not an address a router will forward to other subnets IETF has reserved 169.254.1.0 though 169.254.255.254 for APIPA These addresses are automatically assigned Uses ARP to confirm the addresses are not already in use Always has a subnet mask of 255.255.0.0Multicast vs. Unicast vs. Broadcast vs. Anycast Unicast One station sends information to only one other system Private information is sent between systems Used in web surfing and file transfers Not good for streaming media Broadcast Sends information to everyone at once One packet is sent out, but everyone receives it Only allows a limited scope in what is called a broadcast domain Kept only on a small subnet of a network Used in routing updates, ARP requests, etc. Multicast Delivery of information to interested systems The end station must be configured to accept multicast Used for local type of multimedia delivery Stock exchanges are done over multicast, for example Very specialized and difficult to scale across large networks Anycast Used by IPv6 Selects one out of many nodes based on which one is the closest1.4 Explain the purpose and properties of routing and switching

EIGRP (Enhanced Interior Gateway Routing Protocol) An interior gateway protocol Based on the earlier IGRP Max hop count is 255 This protocol is proprietary to Cisco Hybrid routing protocol that incorporates link state and distance-vector Does not interoperate with other routers EIGRP metrics: Shortest Largest bandwidth Reliability Load Highest Minimum path Maximum Transmission Unit (MTU) It is a hybrid routing protocol A little link state Looks at whether a link is up or down A little distance-vector Looks at how far away a link is Supports multiple protocols (IP, IPX, AppleTalk) Cleanly manages topology changes Speed of convergence is always a significant concern in routing protocols Loop free operation Uses DUAL (Diffusing Update Algorithm) which chooses the best path for traffic Supports minimum bandwidth use Efficient discovery of neighbor routers Uses proprietary Reliable Transport Protocol (RTP) to communicate with different routers RTP is also proprietary to CiscoOSPF (Open Shortest Path First) The most commonly used IGP on the Internet Used internally by most enterprise networks An interior gateway protocol Used within a single autonomous system A link-state protocol Routing is based on the connectivity between routers Each link has a cost Throughput, reliability and round-trip time to make decisions about which direction to send a packet The lowest cost and the fastest path make this determination Identical costs are load balanced Dynamic routing protocol Detects changes in network link state and modifies the routing structure very quickly This happens within seconds Uses Dijkstras algorithm known as SPF (Shortest Path First) Known for low convergence times OSPF routers and links are grouped logically into areas The default area is area 0, which contains the backbone routers of the system Each area has its own database of link states Provides a flexible environment to work with OSPF is used in large organizations/enterprise networks because it is flexible, has fast convergence and has load sharing support (load balancing) Supports authentication and prevents looping by using SPF No IPv6 support until recentlyRIP (Routing Information Protocol) Used in private networks Versions include: RIP, RIPv2, RIPng (IPv6) Been around since 1988 Interior gateway protocol Distance-vector protocol Determines how far away a network is based on number of hops A dynamic routing protocol Max hops of 15 RIPv1 had not authentication and no support for VLSMs RIPv2 is for IPv4 Updated for CIDR and includes built-in authentication to verify the source Maximum hops is 15 before adding information routing table is disabled One of the most popular routing protocols Good for communicating between different routersIS-IS A link state protocol Has a backbone structure and used in backbone routing by ISPs Not intended for use with IP The version that uses IP is called Integrated IS-ISLink State vs. Distance-Vector vs. Hybrid Link state routing protocols Most interested in the quality of the link between point A and point B More complex than distance-vector protocols Allows routers to calculate the best route based on information provided Information passed between routers is related to the current connectivity (quality, bandwidth, availability, etc.) Only shares information about individual route changes (instead of passing on the entire routing table) Not prone to routing loops Considers the speed of the link Very scalable protocol to send traffic This is most often used in large networks Found in OSPF and IS-IS because they are large and scalable Distance-vector routing protocols Most interested in the distance between point A and point B Hops are the only metric used Information passed between routers contains their entire routing tables A copy of a routers routing table is passed to the routers neighbors where additional information is then added If all routers have completed sending their routing tables to each other, the routers are in convergence, or steady-state Usually automatic, requiring very little configuration Good for smaller networks Doesnt scale well in very large networks RIP, RIPv2, or BGP utilize this protocol Path vector routing protocols Designed for very large networks Treats an entire AS as a single node Border and exterior routers pass routing information to the next AS in the chain Uses BGP (Border Gateway Protocol) Hybrid routing protocols Combines link state and distance-vector Not many examples of a hybrid routing protocol EIGRP uses this because of all its different metrics utilize elements from link state and distance-vectorStatic and Dynamic Routing Dynamic Routing Routing protocols that make decisions on their own More reliable, automatically detects problems All automatic and no human configurations are required Builds and updates routing tables themselves Minimal configuration on the router Convergence is handled automatically by the routing protocol The time to converge is based on the protocol Many options for dynamic routing, including RIP, OSPF, or EIGRP Static Routing The human configures the routes manually Can range from being very simple to very complex Every network is different Very common, even in large environments Simple to configure Gives you complete control that dynamic routing does not give you

Routing Metrics Routing metrics will help you decide which direction the traffic will take Different routing protocols use different metrics RIP uses hop counts EIGRP uses a metric between 0 and 4,294,967,295 Windows uses a metric between 1 and 9999 Common routing metrics: Hop-count Speed of the network Throughput Bandwidth Throughput of a network route measured in bits/sec Cost The efficiency of a route. Calculated by Load The amount of bandwidth currently being used. Calculated by Link utilization MTU (Maximum Transmission Unit Size) Determines the largest size of packets that can fit across networks that a route can carry Avoids/reduces the fragmentation of IP packets Path reliability The percentage of time a path is available Packet loss Latency Delay The time it takes for a data packet to reach its destination Next Hop The next hop is useful to determine for troubleshooting or building networks A hop is when a packet passes through a router The next hop is the destination address of the next gateway A router only needs to know how to get to the next router, not every router in the world Time-to-live in IPv4 or hop limit in IPv6 are ways to avoid packet looping Packet looping is when routers send information back-and-forth to each other and the packet does not get anywhere The router determines information about the next hop automatically (dynamic routing) or manually configured (static routing) Looking at a routing table is a good way to determine the next hop A router sees the destination IP address of the packet and looks through the routes in its routing table to find the next best route to send the packetSpanning Tree Protocol (STP) Part of the IEEE 802.1D standard that was designed to prevent loops in bridged (switched) networks Works for switches AND bridges OSI Layer 2 protocol Used everywhere Creates a single loop free path with STA (Spanning Tree Algorithm) Useful for networks to recognize themselves during an outage to prevent looping Switches that are connected to each other via different ports are prone to looping A newer version of this called Rapid Spanning Tree Protocol (RSTP) of the IEEE 802.1w standard Bridges are always talking to each other using MAC-layer multicasts Uses the Bridge Protocol Data Unit (BPDU) to determine which links to block Sends configuration and any topology changes A link will check to see if another link is there every two seconds In a Spanning Tree Protocol: The Root Bridge will be the bridge in which all other bridges are connected to The Root Port is the port on each bridge that the bridge uses to connect back to the Root Bridge The Designated Port is a port on a bridge that sends out traffic The Blocked Port is used to block traffic when there are errors communicating The network will notice that a port is not sending back the two second confirmation and after three attempts to communicate, the network will automatically reconfigure itself without any loops occurring. States of STP enabled bridges/switches Blocking: No forwarding packets at startup Listening: Listens to BPDUs to make sure no loops are occurring Learning: Develops paths in a network and populates MAC address table Forwarding: Ports enter this state if it is a designated port or root port after the learning state Disabled: Administratively disabled ports that are not part of the STP processVLANs (Virtual LANs) Part of the IEEE 802.1q standard Logically separates your switch ports into subnets VLANs cannot communicate to each other without a router Divides network so nodes on the same VLAN communicate as if they were in the same broadcast domain The router/firewall will become the gatekeeper to control the networks traffic from within Switches use VLAN identification: frame tagging to add info to each frame about which VLAN it belongs Groups users together by function based on what the users do on that VLAN VLANs are not limited by distance like LANs on regular switches are They dont need to be physically connected to the same switch Often integrated with NAC (Network Access Control) Multiple VLANs can share the same network wire called a trunk Types of VLANs: Static VLANs: VLANs based on ports The most common type The person will be in the VLAN of the port they plugged into Dynamic VLANs: VLANs based on MAC address No matter where the person plugs in, they will be in the same VLAN To setup a VLAN:1. Designate each port that you want to be a trunk port with 802.1q encapsulation 2. Assign each port a VLAN ID to identify to which VLAN it becomes3. All data frames are tagged with VLAN ID4. Frame tag is removed when the frame reaches it destinationPort Mirroring Replicates traffic passing through a switch Copies packets to a secondary port Built into the switch Useful for many reasons: Protocol analysis Security filtering (IDS) Stream-to-disk Not easy to implement sometimes This is due to switch limitations Some switches simply do not support this Works by plugging a protocol analyzer into a switch and configuring it to duplicate traffic to and from specific devices to the protocol analyzer and the receiving deviceBroadcast Domain vs. Collision Domain Collision domain: A historical footnote A network where a group of nodes can compete with each other for media access The word collision is misleading because collisions were normal in the process of transferring information over Ethernet networks The network was one big segment and everyone heard everyone else signals Similar to ad-hoc networks or NetBIOS networks Think bus topologies Only one station can send data at a time Accomplished through CSMA (Carrier Sense Multiple Access) Stations will listen and send traffic when no communication is occurring A collision occurs when two devices communicated at the same time A difference in signal on the wire occurs when a collision happens and a Collision Detection (CD)(hence CSMA/CD) system picks up on this and sends a signal When networks on collision domains got larger, bridges separated the network into different parts to reduce collisions Very large networks eliminated collision domains by having all devices connect to a single bridge and communicate in full duplex On collision domains, which used hubs, communication could obviously only be half duplex Switches define the size of a collision domain Broadcast domain: A logical area in a network where any node connected to a computer network can directly transmit to any other node without going through a central routing device Deals with the type of packets going across the network rather than the signal like in collision domains Traffic will pass right through the switch/bridge and will only stop once it reaches a Layer 3 device like a router Everyone on the subnet on one side of a router will see the broadcast Like in collision domains, multiple routers are placed in a network to further specialize which systems received the broadcast Only routers can determine the size of a broadcast domain Multiple collision domains can make up a broadcast domain, but multiple broadcast domains can only be one collision domainIGP vs. EGP AS (Autonomous System) Important for understanding IGP and EGP A group of IP routes under common control (clearly defined routing policy) You will configure a network to act as a singe autonomous system IANA assigns an ASN number between 0 and 65,535 IGP (Interior Gateway Protocols) Used within a single AS Not intended to route between different AS OSPF, IS-IS, EIGRP, RIP, and RIPv2 can use this EGP (Exterior Gateway Protocols) Used to route between AS Leverages the IGP at the AS to handle local routing BGP (Border Gateway Protocol) Connects all AS on the Internet Known as the glue of the Internet) Used by ISPs because it supports the implementation of policies and can restrict access This is the standard to make EGP possible Advertises route information about the networks in each AS and the ASNsRouting Tables A list of directions for your packets Every router has a router table Any IP device that needs to send packets out to the network has routing tables This includes printers, workstations, tablets, etc. A routing table will have a destination address, gateway address, interface address and metric (costs associated with that particular route) A packet with a destination/gateway/interface with a loopback address 127.0.0.1 will not leave the device and not enter the network An incorrect address in a routing table will cause a packet to not get anywhere and the end user will not receive any response

Convergence The time of the period between a network change and when the routers respond to this change by updating their routing tables Describes a Zen state where a network is working perfectly When a network changes due to, for example, router reboot, network outage, scheduled maintenance, or denial of service, the time it takes for a network to recover is called convergence time Depending on the routing protocol, convergence time may be small and not visible to the end user Dynamic routing protocols recognize when there is errors in the network and they thus will have different convergence protocols OSPF is fast while RIP is slow Routing protocols are always checking on things and when a change is detected, the network will go into convergence mode to figure out what to do nextTypes of Switches Cut-through switch Forwards data packets as soon as it receives them and does not check for any errors. Uses only the header bits to determine the packets MAC address Fragment-free switch Waits for the first 64 bytes before forwarding in order to check for corruption Store-and-forward switch Calculates the CRC value and compares it to the packets value before forwarding. This is the slowest kind of switch because it inspects a packets entire frame [FCS (Frame Check Sequence)] before forwarding it Multi-layer switch A layer 2 router/layer 3 switch/IP switch. New technology/not standardized Content switch Analyzes content of packets in real-time. Used for load balancing, web caching, and application redirection. Also known as a 4-7 switch because they operate at OSI Layers 4 and 7

1.5 Identify common TCP and UDP default ports

IP is connectionless does not guarantee packet delivery on its own Non-ephemeral ports are permanent ports on a server or service Ephemeral ports are temporary ports determined in real-time on the client workstation TCP and UDP ports are 16-bits in length and can be any number between 0 and 65,535 Well-known: 0 1,023 Established port numbers that are well-known Registered: 1,024 49,151 Available to reserve, but this is not required Used by a responding system to get data back to the client Dynamic: 49,152 65,535 Only used temporarily by systems Port numbers are for communication, not security TCP port numbers are not the same as UDP port numbers Sockets are communication end-points that define a particular protocol, address, and port number Each socket is bound to a particular port number A socket is an end-point for data packets in a network TCP Ports FTP (File Transfer Protocol) TCP/20 (data transfers), TCP/21 (control commands) SSH (Secure Shell) TCP/22 Telnet (Non-encrypted terminal access) TCP/23 SMTP (Simple Mail Transfer Protocol) TCP/25 DNS (Domain Name Services) TCP/53 (zone transfers) HTTP (Hypertext Transfer Protocol) TCP/80 POP3 (Post Office Protocol version 3) TCP/110 IMAP4 (Hypertext Transfer Protocol Secure) TCP/443 UDP Ports DNS (Domain Name Services) UDP/53 (queries) BOOTP/DHCP (Bootstrap Protocol / Dynamic Host Configuration Protocol) UDP/67 TFTP (Trivial File Transfer Protocol) UDP/69 NTP (Network Time Protocol) UDP/123 SNMP (Simple Network Management Protocol) UDP/161

1.6 Explain the function of common networking protocols

TCP/IP Protocol Suite Similar to the OSI model, but only has four layers Specifically created to correlate the model to the real world Layers: Link ARP (Address Resolution Protocol) IP address to MAC address resolution RARP (Reverse ARP) Allows a device to discover its own IP address using only its MAC address Internet Transport TCP (Transmission Control Protocol) Connection-oriented Reliable Sends acknowledgements back is data was received successfully Manages out-of-order messages or retransmissions Analogy: Loads and unloads the moving truck and checks for out-of-order of missing cargo UDP (User Datagram Protocol) Connectionless Unreliable Faster than TCP due to lower overhead No acknowledgements back or recording of data or retransmissions Used with VoIP Analogy: Loads and unloads the moving truck, but doesnt check for out-of-order or missing cargo Application BOOTP (Bootstrap Protocol) Automates the IP address configuration process Allocates IP addresses to devices without any local storage Replaced by DHCP DNS (Domain Name Services) Converts domain names to IP addresses NTP (Network Time Protocol) / SNTP Automatically synchronizes clocks on all devices in a network Useful because it centralizes the times of all logs on client workstations Operates over UDP port 123 Listens on multicast address 224.0.1.1 NNTP (Network News Transfer Protocol) Posts and retrieves news feeds from USENET Operates over TCP port 119 NFS (Network File System) Lets users share files distributes across a network as if they were stored locally Operates over port 2049 SMB (Server Message Block) / CIFS (Common Internet File System) Uses a client-server model to allow networked computers to communicate and share resources like files, printers, and serial ports Uses NetBIOS names (workstations, domains, and AD) Used in Microsoft systems Operates over port 445 CIFS is the most recent version of SMB Has widespread support on Linux and Mac OS ICMP (Internet Control Message Protocol) Sends management messages between systems Reports on the communication between two devices Used with ping, sending echo requests and getting an echo reply IGMP (Internet Group Management Protocol) Manages membership of multicast groups Informs a system of which host belongs to which multicast group Improves efficiency and bandwidth usage in multicast sessions SNMP (Simple Network Management Protocol) Gathers statistics from network devices Queries these devices with requests and the device responds with what was requested SNMPv1 had structured tables and no encryption SNMPv2 had data type enhancements, bulk transfers (asks many things at one time), and no encryption SNMPv3 is the latest version, had message integrity, authentication, and encryption Telnet (Telecommunication Network) Login to devices remotely Unencrypted communication (In-the-clear) Not the best choice for production systems SSH (Secure Shell) Looks and acts the same as Telnet Encrypted communication link (PuTTY) SCP (Secure Copy Protocol) Uses SSH to copy files safely between a local and remote host Can be implemented as a command line utility FTP (File Transfer Protocol) Transfers files between systems Authenticates with a username and password Full-featured functionality (list, add, delete, etc.) Active-mode: uses port 21 to send and port 20 to receive Wont work on NAT or most firewalls TFTP (Trivial File Transfer Protocol) Used in very simple file transfer applications or to boot network devices with no local storage Only reads and writes files No authentication Not used on production systems SMTP (Simple Mail Transfer Protocol) Used most often for sending mail Transferring between mail servers POP3 (Post Office Protocol version 3) For receiving mail from a mail server Downloads the email from the server and then deletes it Designed for intermittent connectivity IMAP4 (Internet Message Access Protocol v4) Flexibility in connectivity Users can access, search, and modify messages Updates mail on the server Keeps the state of the mail (read, replied, deleted, etc.) POP3 is more popular, especially for old servers HTTP (Hypertext Transfer Protocol) For communication over the Internet HTTPS (Hypertext Transfer Protocol Secure) All the power of your browser with an extra layer of encryption through TLS/SSL TLS/SSL (Transport Layer Security / Secure Sockets Layer) SSL Operate over port 443 Created by Netscape Combines digital certificates for authentication with public key encryption A server driven process Limited to HTML, FTP, SMTP, and old TCP/IP applications SSL Steps:1. The client requests a session from a server2. Server responds by sending its digital certificate and public key to the client3. Server and client negotiate an encryption level4. The client generates and encrypts a session key and sends it to the server5. The client and server use the session key for data encryption TLS The updated IETF (Internet Engineering Task Force) version of SSL Has no limitations and is used for everything from VoIP, VPNs, to web pages What you will be using today, even though people might still call it SSL TLS 1.0 = SSL 3.1 TLS 1.1 = SSL 3.2 VoIP (Voice over IP) SIP (Session Initiation Protocol) Initiates, modifies, and terminates sessions VoIP signaling protocol Builds and tears-down media calls RTP (Real-Time Transport Protocol) Encapsulates streaming media content in time-stamped packets Carries the media stream Uses dynamic ports, so it is very difficult for the firewall to block this So SIP sets up the session and RTP is responsible for digitizing the voice and sending it over the network

1.7 Summarize DNS concepts and its components

DNS (Domain Name System) translates human-readable names into computer-readable IP addresses It is hierarchical, meaning that there are many different layers to it It is a distributed database, meaning that there are many DNS servers 13 root server clusters 20 generic top-level domains (gTDLs) 248 country code top-level domains (ccTLDs) DNS hierarchy: . (period) is the top level of the Internet and indicates the DNS root server Top-Level Domains (.com, .net, .edu, .org) Each of these has its own, TLD, servers Websites (professormesser.com) These have second level servers Servers (www, live, mail, east, west) FQDN (Fully Qualified Domain Name)63 characters max

The human readable version of a website Must contain a host name and a domain nameTDLHost NameDomainName

mail.ucdenver.edu

255 characters maxFQDN

DNS Servers Authoritative Servers Stores IP and FQDNs of systems on a domain Cache-only Servers Only forwards requests and caches some common ones Parts of a DNS server: Forward Lookup Zone Where IP addresses and FQDNs are stored The most important part of a DNS server Reverse Lookup Zone Enables a system to determine an FQDN based on an IP address Uses the PTR record Cached Lookups Stores already resolved FQDNs The DNS process Resolver: Applications on the computer look in the HOSTS file on the computer to see if the FQDN is local on the computer A HOSTS file is a plaintext file on a host machine containing DNS info Local Name Server: Looks for cached FQDNs of previous searches by other people Has lists of all root servers on the Internet for further searches Root Server: Determines which server to look for the FQDN This will transfer the request to the .com Name Server, .org Name Server, ProfessorMesser.com Name Server, etc. Results of these searches will be cached, so this whole process wont happen every time DNS zones A zone is an area or namespace located within a domain over which a particular DNS server has authority Primary zone: all changes to a zone must be through a primary DNS server Secondary zone: DNS server hosts a read-only copy of the table from the primary serer Records are transmitted via zone transfer DNS records Resource Records (RR) The database records of domain name services within the DNS server Over 30 different RR types Forward Lookup File stores all the resource records Address records (A) (AAAA) Defines the IP address of a host and maps the host name to the IPv4 address This is most queries A records are for IPv4 addresses Modify the A record to change the host name to IP address resolution AAAA records are for IPv6 addresses Maps the host name to the IPv6 address The same DNS server, different records Canonical name records (CNAME) Assigns one or more aliases to a host A name is an alias of another, canonical name One physical server, multiple services For example: broadcast.com gets redirected to yahoo.com Mail exchanger record (MX) Determines the host name for a mail server This isnt an IP address; its a name Name server record (NS) Lists the name servers for a domain Delegates a DNS zone to use the given authoritative name servers NS records point to the name of the server Pointer record (PTR) The reverse of an A or AAAA record Added to the Reverse Map Zone file SRV (Service Locator) record Used to identify a host that provides a specific service SOA (Start of Authority) record Contains authoritative information for a zone including the primary DNS name server, contact details for domain admin, domain serial number, and zone refresh times Only one SOA record can exist per zone Dynamic DNS Dynamic DNS Update (DDNS) Updates the name server records with a secure, automated process DHCP means the addresses change all the time, so the end-stations inform the DNS server of their IP address and thus DDNS is used to update the name server with these new addresses automatically Part of Windows Active Directory Domain controllers register in DNS Allows other computers the domain to find the AD servers Dynamic DNS Services (DDNS) are designed for SOHO dynamic IP addresses The ISP dynamically assigns IP addresses Built into many SOHO routers accessible via the Internet (192.168.0.1) DNS name resolution process1. Client request a name resolution2. DNS server queries a root name server3. Root name server responds with the IP address of the DNS server for the TLD4. DNS server queries TLD server5. DNS server queries other domain servers if necessary6. Host name is resolved7. Resolved address is returned to the client

1.8 Given a scenario, implement the following network troubleshooting methodology

Steps for troubleshooting a network:1. Identify the problem Information gathering, identify symptoms, question users with open ended questions, and determine if anything has changed Recreate the problem yourself2. Establish a theory of probable cause Question the obvious first3. Test the theory to determine cause Once theory is confirmed, determine next steps to resolve problem If a theory is not confirmed, re-establish a new theory or escalate 4. Establish a plan of action to resolve the problem and identify potential effects5. Implement the solution or escalate as necessary6. Verify full system functionality and if applicable, implement 7. Document findings, actions, and outcomes1.9 Identify virtual network components

Virtual Machine Manager (VMM) Virtual machines are not portable Hypervisor is a popular VMM Bridges the virtual world to the physical world Maintains separation between virtual machines Types: Type 1: Bare Metal The hypervisor IS the operating system Software to load includes VMware ESXi, or Microsoft Hyper-V Type 2: Hypervisor runs in the existing OS Used in virtual desktop environments Virtual Servers All virtual networks have virtual desktop servers disabled by default Runs its own OS application and has its own software-based CPU, NIC, RAN and hard drive Type 1: Bare Metal install Multiple CPUs with multiple cores RAM needs to be over 128 GB Multi-terabytes hard drive arraysVirtual Desktops Requires hosting servers endpoint devices, connection brokers, management infrastructure, and application delivery and execution infrastructure Connection brokers manage connections between host servers and end point devicesServer Consolidation Physically shrinks the data center Increases flexibility Lower cost (electricity, cooling, etc.) Management benefits include fast deployment and load management between serversVirtual Switches Virtual switches are software-based switches that connect systems on a virtual network A virtual switch cannot communicate directly to another without the use of a router Two VLANs cant communicate directly without a router All servers on a virtualized network are connected with enterprise switches and routers Different virtualized environments that communicate with each other can be managed by a virtual switch Features of using a virtual switch include load balancing and QoS and are easy to apply No physical wires Also gives the ability to virtualize firewalls and IPSsNetwork as a Service (NaaS) Moves the virtualized network into the cloud Referred to as cloud computing No physical hardware The network becomes invisible because the network is running as a service at a third party facility Network changes are also invisible If you have an important application running over the web, it is a good idea to move the network to the cloud for more efficient management by a third party Examples include Office 365 cloud subscriptions and Adobe Creative CloudOnsite vs. Offsite Virtualization Onsite virtualization Allows you to manage your own infrastructure Build it, host it, maintain it Advantages include giving you complete control, flexibility to change an shift as needed, and secure as you need Disadvantages include the fact that it is costly, requires significant networking infrastructure, and not easy to upgrade Offsite virtualization Allows you to virtualize in the cloud Requires a stable Internet connection Advantages include no infrastructure costs, management is handled by others, geographical flexibility, and seemingly unlimited upgrade options Disadvantages include the fact that data is in the cloud and there are contractual limitations Not a great option if your data is extremely sensitive Virtual PBX PBX (Private Branch Exchange) Your business phone system Usually more than just a phone Interactive voice response, voice mail, reporting, and music on hold Very reliable You will know when there is a problem with your PBX Virtual PBX is a cloud-based voice service No infrastructure besides the phone Additional network configurations may be required More bandwidth and QoS settings Virtual PBX gives you big cost savings Low cost call routing through the Internet

2.0: NETWORK INSTALLATION & CONFIGURATION

2.1 Given a scenario, install and configure routers and switches

Types of Routers Access routers Located at remote sites, used in SOHO networks Distribution routers Collects data from multiple access routers and redistributes the data to a primary enterprise location Core routers Designed for use in the center of a network backbone and connects multiple distribution routersRouting Tables The name, destination, and next hop are determined for all possible directions A default route should also be configured Redundant routes in a routing table should have precedence over one another You need to visually look at a network to really determine how the routing tables should be configured Routers each change the packets MAC address to the MAC address of the router in the next hop, but never the IP address of the packet Types of routes: Directly connected routes Remote routes Host routes Packets go to a specific IP address Default routes Parts of a routing table:Network DestinationNetMaskGatewayInterfaceMetric

Address of host destinationsDetermines the extent to which the destination address must match the Network Destination before that route is usedAddress of a packets first hop/adjacent routerWhere data is sent after the Network Destination is determinedCost of a route based on hops or other various criteria

NAT (Network Address Translation) Internet security that conceals internal routing schemes with an external address A router or firewall will perform Layer 3 conversion to convert one IP address to another NAT is a one-to-one IP address conversion No other addresses change Destination NAT (DNAT) or Static NAT Converts the destination IP address to another IP address External to Internal Individual port numbers of external traffic are picked up and the address is converted and routed to the appropriate server Used to convert externally accessible IP addresses to an internal address Address is converted into a specific address PAT or Source NAT (SNAT) Converts a source IP address to another IP address Internal to External (192.168.0.1 to something unique before getting onto the Internet) Often used to convert a large number of internal IP addresses to one external address Uses Dynamic NAT to map an unregistered address with a single registered address using multiple ports 192.168.0.1 / or home routers Used in SOHO networks A translation table is held to keep track of what the original IP addresses were Also known as Overloaded NAT Dynamic NAT IP address is converted based on the first available address from a poolVLAN Used to subnet a network to separate users and servers Assign switch ports to a subnet (VLAN) This can also be done automatically with Network Access Control (NAC) Connect your switches together with trunks A trunk is a specially designed port between switches for many different VLANs as a way to travel to a destination together Configuration of VLANs can be done at the command line or in graphical (web based) interfaces Trunks must be setup properly so all the VLANs can communicate within the same subnetManaged vs. Unmanaged Switches Unmanaged switches Plug and play Very few configuration options Fixed configurations, so no VLANs Very little integration with other devices No management protocols Low cost Managed / Intelligent switches Allow you to monitor and configure their operation Has its own IP address and a configuration interface VLAN support (802.1q) Traffic prioritization (QoS) Redundancy support For STP (Spanning Tree Protocol) where many switches are connected External management (SNMP) Port mirroring to capture packetsInterface Configurations Ethernet has many different configuration options and both sides need to match Auto: Devices on both ends will auto negotiate so they both match configurations Not perfect, mismatches could result Half-duplex and Full-duplex are other configuration options that must match: You can also configure port speeds (10, 100, 1000, Auto) IP addresses, subnet masks, and default gateways are part of the Ethernet configuration options MAC filtering can be used for interface configuration in wireless networksPoE (Power Over Ethernet) Power is provided on an Ethernet cable along with the data Phones, cameras and WAPs are examples of devices that use this Useful in hard-to-power areas Power is provided at the switch Switches with built in power are called endspans Switches with in-line power injectors are called midspans PoE is part of the IEEE 802.3at-2009 standard and provides 25.5 watts of power Mode A (Power is on the same wires as the data) Phantom power Mode B (Power is on the spare wires) All four pairs are requiredTraffic Filtering Blocks unwanted traffic from entering a network Most often done at the router or firewall Not much filtering occurs at the switch Can be done in almost any router, even the small SOHO routers URL filtering Block based on browser URL Port filtering Block based on destination port number Scheduling Set different kinds of filtering to occur at a certain time of the dayDiagnostics Switches and routers can have built-in diagnostics Routers and switches can have built-in hardware tests They can also provide ongoing monitoring for statistics using SNMP or through the command line They can have protocol diagnostics using ping and tracertVTP Configuration (VLAN Trunking Protocol Configuration) VLAN Trunking A trunk link connects various VLANs with a single switch Manual configuration with many VLANs on a switch can be difficult Cisco created VTP to automatically configure VLANs Configure one switch and VTP transfers those settings to the other switches Eliminates the overhead in porting a VLAN in another network MVRP (Multiple VLAN Registration Protocol) does this on non-Cisco switches UTP on a switch: Server mode: default Client mode: Cannot modify VLANs Transport mode: Configuration is not transmitted to other switches in the groupQoS (Quality of Service) Manages and controls different kinds of traffic passing through a network All traffic, by default, has the same priority and there is no way to control it Because of the diverse kinds of traffic on the networks (voice, data, video, etc), QoS can set priorities for these different kinds of traffic IntServ (Integrated Services) uses specialized protocols to reserve network resources DiffServ (Differentiated Services) uses QoS bits that are enabled in the IPv4 header Routers and switches need to take in account these QoS Not all routers or switches want to read the QoS bits Bandwidth management Traffic shaping/rate limiting Only allocate certain amounts of bandwidth to certain types of traffic Scheduling algorithms Queues different packets and picks who gets to go first Congestion avoidance Uses Random Early Detection (RED) to drop packets before the buffer fills Packets will be resent until they can go through Policing Drops any packets that go over the configured limit Explicit Congestion notification Avoids drops by informing the upstream to slow down QoS parameters An SLA is used to define QoS parameters Bandwidth Latency Jitter Packet loss EchoPort Mirroring Copies packets on one switch port to another port Refers to the physical port on a switch (not TCP or UDP ports) Not available on all switches Not always the most functional on switches that do allow it Cisco: Switches Port Analyzer (SPAN) 3Com: Roving Analysis Port (RAP) You will configure the switch to send these copied packets to and from specific devices Useful for monitoring traffic behind the scenes to understand whats happening on your network better

2.2 Given a scenario, install and configure a wireless network

Wireless LANs An STA is a device on a wireless network A DS (Distribution System) is a wired connection between BSS and the premise-wide network Provides mobile access not network resources Service Sets BSS (Basic Service Set) A set of devices with an AP connected to a wired network and has one or more clients Extends the distance between wireless endpoints by forwarding signals through the AP All devices that connect to any particular AP are known as the BSS IBSS (Independent Basic Service Set) Describes a peer-to-peer network Each station is a transmit and receive ESS (Extended Service Set) Multiple BSSs for mobility purposes The full group of participants in a large WLAN that includes more than one AP Types of wireless communication on a LAN RF (Radio Frequency) Broadcast radio = non-directional, single frequency Spread spectrum = more than one frequency Difficult to tap Uses: FHSS (Frequency Hopping Spread Spectrum) DSSS (Direct Sequence Spread Spectrum) Infrared SIR (Serial Infrared) 4.6 115.2 kbps MIR (Medium Infrared) 0.576 1.152 mbps Overall transmission from 10 16 mbps Bluetooth 30 feet max Uses a radio frequency Version 1.1 = 2.4 GHz @ 1 mbps Version 2.0 = 2.1 3 mbps @ 100 feet Microwave Pulses of electromagnetic energy 1 GHz 300 GHz Prone to interference Used in satellite networks Use a wireless repeater to extend a wireless networkWAP Placement Access point placement should be centered around the users, their conference rooms, desktops, and other large meeting areas Keep in mind the metal and concrete between the WAP and users Antenna choice is important Multiple access points with 20 - 25% overlap is justifiable for a maximum efficient range Keep in mind these should be different frequenciesAntenna Types Omnidirectional antennas One of the most common Included on most access points Signal is evenly distributed on all sides Good choice for most environments Disadvantage: No ability to focus signal Directional antennas Focuses the signal in a particular direction Sends and receives signal in a single direction Focused transmission and listening Antenna performance is measured in dB Double power every 3dB of gain Yagi antenna Very directional and high gain Looks like a stick Found on rooftops to send signal from one direction to another Parabolic antenna Focuses the signal to a single point Looks like a dish Gain is the ratio of input and output power of an antenna Larger the antenna, lower the frequency of transmitInterference Wireless signals are like any other radio signal 2.4 GHz, 3.7 GHz, 5 GHz Radio signals are always susceptible to interference from external sources or manmade ones Predictable interference: Florescent lights Microwave ovens Cordless telephones High-power source Unpredictable interference: Multi-tenant building with multiple WAPs You can see interference problems with netstat -e on Linux and Performance Monitor in Windows A spectrum analyzer helps you visually see interferenceFrequencies and Channels IEEE 802.11 standards for wireless networking set specific frequencies 14 total wireless channels, but only 11 can be used in the US Only use channels 1, 6, and 11 for optimal performance in networks with multiple APs 5 GHz Used in 802.11a and 802.11n 802.11a uses Dynamic Frequency Selection (DFS) Avoids interference with weather radar and military satellites Uses OFDM (Orthogonal Frequency Division Multiplexing) Transmits multiple data streams over a given bandwidth 23 non-overlapping channels / different channels used in different countries 802.11n uses MIMO (Multiple-Input and Multiple Output) Uses more than one antenna Supports 4 transmits and 4 receives and sending/receiving 4 data streams 2.4 GHz Used in 802.11b, 802.11g and 802.11n Uses Direct Sequence Spread Spectrum (DSSS) Data is chipped and transmitted across different frequencies in a predefined order 14 channels 2 MHz wide spaced at 5 MHz intervals 11 of these channels are used in the United States 802.11g and 802.11n Also uses OFDM Same frequencies as 802.11b, but a different modulation scheme 802.11g uses channels 1, 5, 9, and 13 Non-overlapping 20 MHz OFDM channel scheme Uses DSSS for slower speeds 802.11n uses channels 3 and 11 40 MHz OFDM channel scheme 3.7 GHz Licensed spectrum was added with 802.11y-2008 Used in 802.11a Range of up to 5,000 meters Only in the United StatesWireless Standards All wireless standards are managed by the 802.11 committee (IEEE 802) Modes: Infrastructure mode: One or more APs in a BSS or ESS Ad hoc mode Peer-to-peer connections with IBSS 802.11a Original wireless standard released in October 1999 Operates at the 5GHz range or 3.7 GHz with special licensing 54 Mbit/s 150 feet max More realistically, you get 6, 12 and 25 Mbit/s Smaller range than 802.11b 802.11b Came out at the same time as 802.11a Operates at the 2.4 GHz range 11 Mbit/s 125 feet max Better range than 802.11a Less absorption problems More things created interference at this range (baby monitors, cordless phones, Bluetooth, etc.) 802.11g An upgrade to 802.11b Operates at 2.4 GHz range 54 Mbit/s 125 feet max Backwards compatible with 802.11b Same interference problems as 802.11b 802.11n The latest standard Operates at both 5 GHz and 2.4 GHz 600 Mbit/s 225 feet max Uses MIMO 802.11ac Operates at 56 GHz Speeds of up to 1 Gbps Compatibility (802.11 a/b/g/n) 802.11g introduced the need for wireless standards to be compatible with each other Due to its requirement to be compatible with 802.11b Mixing standards will reduce the speed 802.11n attempted to maintain compatibility with the older wireless standards by offering 2.4 and 5 GHz Legacy mode: acts as 802.11a, 802.11b, or 802.11g Mixed mode: Transmits older technologies along with the new Interoperability feature adds additional performance costs A pure network made up of one standard is the best way to reach the maximum speeds of that standard 802.22: WRAN (Wireless Regional Area Networks) Used in rural areas with lower network usage Uses 54 and 862 MHz of whitespace television signals Point-to-multipoint 18 miles distance limitation for users, but 60 miles for enterprises Similar to DSL in speed 1.5 Mbps down / 384 Kbps upSSID Management SSID (Service Set Identification) A 32-bit alphanumeric string that identifies a wireless network by a recognizable name Every AP comes with a default SSID BSSID (Basic Service Set Identification) An identifier to the BSS in which all devices on a WLAN are connecting to a particular AP The MAC address of the access point Not usually seen by the end user SSID is often configured to broadcast Can be disabled However, if you know the name you can still connect ESSID The common SSID given to the APs in a network thats large enough to require more than one AP Some programs can act as fake access points

2.3 Explain the purpose and properties of DHCP

DHCP IP address configuration used to be manual before BOOTP came along in 1993 Bootstrap Protocol (BOOTP) didnt automatically define everything and didnt know when an IP address might be available again DHCP replaced BOOTP in 1997 DHCP Assignment process (DORA): Step 1: DHCP DISCOVER A device will send a BOOTP broadcast with the address of 255.255.255.255 (every device on the network sees this) over UDP port 67 until it reaches a DHCP server A DHCP relay service will act as a messenger by sending requests to the DHCP server as a unicast transmission Step 2: DHCP OFFER Once the DHCP receives the broadcast it sends an offer with an IP address over UPD port 68 back to the client workstation Step 3: DHCP REQUEST Once the client workstation gets offers from all the DHCP servers, it makes a decision of which one to use and it sends a broadcast out to an identifier to the desired DHCP server A node will accept the first address it is offered Step 4: DHCP ACKNOLAGEMENT DHCP server sends another broadcast to acknowledge that it has accepted the transactions Contains the IP address and settings for a lease period DHCP server keeps track of assigned addresses so multiple assignment wont occurReservations A DHCP can provide IP addresses via dynamic allocation Addresses are handed out and given back to the DHCP server as devices join and leave the network Automatic allocation Similar to dynamic allocation, DHCP will keep a list of past assignments and youll always get the same IP address overtime you connect to the network Static allocation Administratively configured The admin will put in a list of MAC addresses and set to assign a particular IP address to that MAC address Also known as Address Reservation or IP ReservationScopes A scope is a grouping of IP addresses for a section of a network Each subnet has its own scope A scope is generally a contiguous pool of IP addresses DHCP exceptions can be made inside the scope Scope properties: IP address range, subnet mask, lease durations, DNS server, default gateway, etc. A DHCP server must be configured with at least one scope Configured with name, description, IP range, lease periods, subnet mask, default gateway address, domain name and IP address of a DNS serverLeases A DHCP lease is temporary, but can seem permanent Setup by DHCP server as an allocation of addresses Administratively configured DHCP servers can reallocate IP addresses to common clients A lease length is 8 days by default, but can be configured differently A workstation can manually release its IP address DHCP renewal T1 Timer Check in with the lending DHCP server to renew the IP address 50% of the lease time (by default) T2 Timer If the original DHCP server is down, try rebinding with any DHCP server 87.5% of the lease time (7/8ths) The lease time of a DHCP lease is 8 days During the 8th day, you enter the rebinding period where if you still cannot communicate with the original DHCP server, you will go to another one to renew your leaseOptions A special field in the DHCP message contains many options 254 usable options (256 options total) Common options include subnet mast, DNS server, domain name, etc. Options such as 129: Call Server IP address or 135: HTTP Proxy for phone-specific applications Global options: apply to all scopes Scope options: apply to only a particular scope Class options: apply to nodes specifying a class Registered client options: applies to scope reservation for IP addresses Options are configured on the DHCP server, but not all DHCP servers offer this

2.4 Given a scenario, troubleshoot common wireless problems

Interference A site survey can help you see what frequencies other networks around you are using External sources may be outside your influence Signals may bounce off of obstacles and obstructions Signal strength Interference weakens signal strength Transmitting signal, transmitting antenna or the receiving antenna impact signal strength Incorrect channel Channel selection is usually automatic, so look for a manual tuning option Bounce and latency Multi-path interference and flat surfaces create bounce and thus latency Incorrect WAP placement Locate closer to users Configurations Basic configuration settings include the IP addressing, uplink/WAN connection on the WAP SSID mismatch is when two APs have incorrect names that make it so you cant move from one side of the building to another or when a device has a different SSID than the AP Incompatibilities WAP must be backwards compatible with older wireless standards Encryption type WPA, WPA2, WPA2-Enterprise, and encryption keys are all methods of encryption that must be compatible with users and multiple WAPs

2.5 Given a scenario, troubleshoot common router and switch problems

Switching Loops Spanning Tree Protocol is often used to prevent this This is a big fear for network admins Switches communicate by MAC address, and nothing at the MAC address level exists to identify loops Broadcasts and multicasts are sent to every port on the switch This is often a problem IP addresses have TTL that prevents infinite looping, but switches dont have TTL Looping can be cause by both ends of a cable that are plugged into the same switch Loops use up a lot of resources The only way to fix loops is to unplug the cable in question if Spanning Tree Protocol is not in place How routing protocols avoid routing loops: Defining infinity: any packet should reach it destination in 15 hops or less. Any more hops will result in the packet being dropped Split horizon: a router wont inform another router about a route if information about that routers destination came from it Use of a hold-down timer: a router suspends a route that fails to deliver packets for a couple of minutesBad Cables/Improper Cable Types Troubleshoot the cables themselves if you cannot get a connection Slow throughput can often be caused by a bad or improper cable Intermittent connectivity is also caused by bad cables Troubleshooting steps: No connection: Is the cable crimped? Is the a link light? Is the cables punched correctly? Swap the cable Slow throughput: Do you have a link light? Is the cable damaged? Swap the cable Intermittent connectivity: Check for link light flickering Swap the cable Swapping the cables is the number one thing you can do to fix a network cabling issue A short can occur if a cable is broken or damagedPort Configuration Poor throughput is defined by consistent issues that are easily reproducible No connectivity? Check link light Auto vs. Manual configuration Both sides must be the same configuration Auto configuration is not perfect, so manual configuration is a good troubleshooting step Speed must also be the same on both sides If duplex is mismatched, the speed will suffer VLAN configuration can also be an issue, so check to make sure you are plugging a port into the right VLAN You can always restore a port to its default settingsVLAN Assignment Not completely obvious to troubleshoot No connectivity is defined by having a link light, but not able to ping, or nodes on a different network segments unable to communicate IP related issue VLANs either work or dont work because everything is done by IP address and you cant have a VLAN on the wrong subnet Check the documentation to compare to the switch configuration Verify IP addressing, especially if you are statically assigning IP addresses Subnet is critically important Confirm trunk configurations Is the VLAN part of the trunk? Is the switch port configured for a trunk on both sides? A trunking error occurs when the VLAN definition is not broadcast to all switches on the LAN If you change the VLAN configuration, update the client IP addressMismatched MTU/MUT Black Hole MTU (Maximum Transmission Unit) is the maximum size an IP packet can be to transmit over a network without having to fragment it Fragmentation slows things down (overhead is involved) Losing a fragment loses an entire packet Programs include a fragment bit to prevent this Difficult to know the MTU all the way through the path Automated methods are inaccurate (filtered ICMP) A TCP/IP handshake will not occur and a connection wont be established Ethernet frame properties:

DLC Header (14 bytes)IP Header (20 bytes)TCP Header (20 bytes)TCP Data (1460 bytes)FCS (Frame Check Sequence) [4 bytes]

Total data: 1518 bytes Individual systems can be configured to send less TCP data to avoid fragmentation MTU sizes are usually configured once between two connections MTUs are a significant concert for tunneled traffic A tunnel may be smaller than your local Ethernet segment Routers will respond back and tell you to fragment if you send packets with DF (Dont Fragment) sent ping -f -l [bytes] [IP address] will allow you to set the ICMP length/size of the data and a separate server on the Internet On Mac OS X use ping -D -s [bytes] [IP address]Power Failure Easy to troubleshoot in person Not as easy from a remote site Check to see if there are external power outages Check the power supplies of switches and routers Intermittent connectivity of switches and routers can be because of the power supply Use a UPS to prevent these issues Make sure you add redundancy to your system to plan for the worst Audit your data center power to prevent the circuit from breaking/overloading Monitor ongoing power usage with built-in sensors or log outagesBad/Missing Routes An initial failure to communicate is usually a configuration issue A complete failure after the router was running for a while is a larger issue Intermittent connectivity on routers can be caused by configuration issues Perform a trace route to follow your routing tables in both directions to see the path all the way to the other side May require communication with 3rd-parties If the router is using dynamic routing tables, it makes it easier to troubleshoot because you can see the routes currently active Uses SNMP and ping to monitor the routesBad Fiber Modules No connection is verified by no light at all An SFP module or GBIC module are modules that holds fiber connections Throughput may be slow and connectivity may be intermittent Make sure the switch and router support certain modules or fiber type Never mix and match fiber modules and types of fiber Fiber is easily replaceable, so you can just swap out the fiber module If the fiber module is not the problem, test the fiber Monitor the status of the connection overtime to prevent future error more efficiently CRC errors?Wrong Subnet Mask and Gateway A wrong subnet can be the result of devices on a LAN not communication with each other Check your documentation for the proper settings for these Monitor the traffic to examine local broadcasts Check the devices around you to determine if these settings are consistent or not over multiple devices Take advantage of tracert and pingDuplicate IP Address Static IP address assignments must be very organized to prevent duplication DHCP is not perfect either, sometimes multiple DHCP servers overlap and rouge (unofficial) DHCP servers may exist Use ipconfig to check and change the IP address to be outside the DHCP scope Intermittent connectivity is a sign you have an issue with a duplicate IP address Duplicate IP addresses may be blocked by the OS, so the OS will notify you Always ping an IP address before static addressing Ping 127.0.0.1 to verify that IP is working Request timed out means that no response was received from the device Host unreachable means that a host was not reached with the IP address specified Put a packet capture device on the network to monitor the DHCP process to see if DHCP is an issueWrong DNS If there is not Internet access, wrong DNS can be an issue Definitely a problem if ping works, but the browser does not Check the IP address of the DNS server by performing an nslookup Try changing the DNS server to troubleshoot

2.6 Given a set of requirements, plan and implement a basic SOHO network

List of Requirements SOHOs are networks designed for a 1 to 10 person range SOHO networks are always a remote site You need to think about what applications (VPN, web based, etc.) and what data sharing (backups, data management) is needed for a particular networkSOHO Cabling A small office network may need an electrical contractor to come in, while a home office has very basic requirements A SOHO network is often wireless, so no cabling may be needed Cabling at a SOHO office do not change often, so setup only happens one time Cable length must not exceed 100 meters in a SOHO networkDevice Types A DSL or cable modem is provided by the ISP quite often These have features such as NAT (Network Address Translation) They also have built-in wireless, content filtering, etc. An Ethernet switch may be part of the router All-in-one printers are the perfect choice for a SOHO networkEnvironmental Limitations A SOHO has limited support for advanced hardware Temperature needs to be cool and the area where main hardware is needs to be ventilated Humidity must be kept low and the air must be conditioned A UPS is also a good idea for a SOHO When the SOHO network uses wireless, make sure you avoid the basic conflicts

Equipment Limitations SOHO equipment is smaller and less capable due to smaller network and power requirements There is also performance limitations with SOHO hardware Redundancy limitations, no automated failover Management and upgradability limitationsCompatibility Requirements SOHO devices are all configured the same way from ISPs so that troubleshooting is easy SOHO networks have standardized networks and identical configurations Support is abundant due to these standardized factors Operating Systems are among the strict compatibility requirements of SOHOs

3.0 NETWORK MEDIA AND TOPOLOGIES

3.1 Categorize standard media types and associated properties

Fiber Transmission by light Very difficult to monitor tap, as there will be a noticeable signal loss Signal is slow to degrade and efficient for communication over long distances Cladding surrounds the core and reflects light back into it Immune to radio interference Multimode fiber Light bounces off the sides of the cable Short-range communications 2km or shorter Used for going between different buildings or in even one building Inexpensive light sources like LEDs are used Graded-index MMF Better prevents light dispersal by the center of the core being faster than the outer core Singlemode fiber Light is one straight line through the cable Used for long-range communication 100km without processing 30 MHz bandwidth Expensive light sources like laser beams are used Has a smaller core than MMF Step-index SMF Total internals reflection is used where the speed of transmitted light is higher than the cladding and a step down occurs which reflects all light back into the core If you cut a fiber cable, you must polish the rough edges so light is not displaced as it leaves the fiber Consists of:

Copper Coaxial Two or more forms of the cable share a common axis Used in older Ethernet networks 10Base5 (Thicknet) RG-8/U, 10Base2 (Thinnet) RG-58 RG-8 cables implemented in Thicknet networks required vampire taps, which cut into the cable to establish a connection Today it is used in television/digital cable Broadband Internet RG-9 cables are used in cable television/modem applications RG-62 cables are used in ARCNET networks RG-59 cables send video signals to another location RG-6 cables are used for DSL and cable TV Twisted pair Uses balanced pair operations Two wires have equal and opposite signals (Transmit+, Transmit- / Receive+, Receive-) The twist of the cables keeps the cables away from interference Each cable has a different twist rate STP (Shielded Twisted Pair) Additional shielding that protects against interference Requires the use of an electrical ground UTP (Unshielded Twisted Pair) No additional shielding The most common twisted pair cablingCable Categories The EIA (Electronic Industries Alliance) is an alliance of trade associations that creates standards for the computer industry The TIA (Telecommunications Industry Association) has the standards of ANSI/TIA/EIA-568 Category 3: One of the first standardized categories Supported 10 Mbit/s Ethernet and 4 Mbit/s Token Ring Category 5: Update from Category 3 Supports 100 Mbit/s Ethernet Category 5e: Update from Category 5 Supports up to 1 Gbit/s Gigabit Ethernet Tighter specifications for the cable and connectors Category 6: Supports up to 10 Gbit/s Ethernet through 55 meters Category 6a: Designed for 100m of 10 Gbit/s Ethernet Category 7: 1 Gbps to 10 GbpsStraight-Through cables Patch cables Network jack to a patch panel Cables that connect a network device to a jack are also known as drop cables The most common Ethernet cable Connects workstations to network devices Wires go straight through the cable to an equivalent connection Two types of network ports: MDI (Media Dependent Interface) is usually a NIC Pin 1: Transmit+ Pin 2: Transmit- Pin 3: Receive+ Pin 6: Receive- MDIX (Media Dependent Interface Crossover) is usually a network switch Pin 1: Receive+ Pin 2: Receive- Pin 3: Transmit+ Pin 4: Transmit-Crossover cables Used to connect MDI to MDI (Workstation to Workstation) Used to connect MDIX to MDIX (Switch to Switch) Auto-MDIX is on most Ethernet devices Automatically decides to cross over If this is enabled on the NIC, a crossover cable is not needed T1 crossover cable Used for CSU/DSU to CSU/DSU Takes a signal from the wide area network (T1) to a router Rollover cables The wires in a TIA58 configuration are flippedPlenum Cables The plenum is the area inside the fake ceiling of an office building A plenum-rated cable has a cable jacket with PVC (polyvinyl chloride) or FED (Fluorinated Ethylene Polymer) Not as flexible as regular cables Cables for risers (between-floor connections) do not have as strict requirements as plenum spacesMedia Converters Media conversion happens at OSI layer 1 Coaxial cables can be extended by converting its signal to a fiber cable in the middle and then back again Copper to Fiber/Fiber to Copper conversions require powered connections You can convert from singlemode to multimode fiber without the power requirements, but uses mirrors Fiber to coaxial converter allow fiber for the use of home networks

Media Distance and Speed Limitations 10Base5 (Thinknet) uses the RG-8U coaxial cable running at 10 Mbit/s for 500 meters 10Base2 (Thinnet) uses the RG-58A/U coaxial cable running at 10 Mbit/s for 185 meters 10Base-T uses Category 3 twisted pair cables running at 10 Mbit/s at 100 meters 100Base-TX uses Category 5 twisted pair cables running at 100 Mbit/s at 100 meters 1000Base-T uses Category 5e or Category 6 twisted pair cables running at 1000 Mbit/s at 100 meters 10GBase-T uses Category 6 twisted pair cables running at 10 Gbit/s at 55 meters 10GBaseT also uses Category 6a twisted pair cables running at 10 Gbit/s, but at 100 meters instead Multimode fiber uses: 100Base-FX running at 100 Mbit/s at 2km 1000Base-SX running at 1000 Mbit/s at 200-500 meters 10GBase-SR running at 10 Gbit/s at 300 meters Singlemode fiber uses: 1000Base-LX running at 1000 Mbit/s at 2km 10GBase-LR running at 10 Gbit/s at 10kmBroadband over Powerline (BPL) Broadband transmission over existing power lines Can provide Internet access via the power line connections Good for remote locations Useful for home automation to control devices from afar Uses radio communication over many different frequencies BPL is the IEEE 1901 standard called Homeplug AV Speeds: Low Speed: narrow band (15 to 500 kHz) Medium Speed: 9 to 500 kHz at 576 kbps Interference is a big problem with BPL Insecure, sends data in plaintext

3.2 Categorize standard connector types based on network mediaFiber ST (Straight Tip) Bayonet connector Push it in and turn it to lock Most commonly used in multimode patch panels SC (Subscriber/Standard/Square Connector) Weaker lock Connecters are stuck together in pairs (for transmit and receive) Transmit and receive will be different colors Used in duplex configurations LC (Lucent/Local/Little Connector) Smaller than ST or SC Also packaged in pairs Locks on top of the connector (push down to release) Can be used in SMF or MMF MT-RJ (Mechanical Transfer Register Jack / Media Termination - recommended jack) Same size as a RJ-45 cable for the same amount of real estate can be used for fiber Both transmit and receive are combined into one connection Smallest type of fiber connection Used in MMF applications Also called fiber jack FC (Face Contact) Heavy duty connections for industrial purposes Strong ceramic or metal center tube Round-shaped FDDI (Fiber Distributed Data Interface) Also called a MIC (Media Interface Connector) 2 connectors that snap into a receptacle Used for multimode connections at full-duplex SMA (Sub Miniature type A) Waterproof connection Threaded tube on the outside Bionic Connectors Screw on connectors that are now obsolete Copper RJ-45 An 8 position, 8 conductor (8P8C) connector Modular connector RJ-11 A 6 position, 2 conductor (6P2C) connector RJ14 uses 6P4C for dual-line use Only two wires/conductors are involved in telephone connections BNC (Bayonet Neill-Concelman) Used for Ethernet connection over Coaxial Often seen on 10Base2 networks with RG-58 Rigid and bulky F-connector Used for cable television Used with RG-6/U and RG-59 cabls Twists in T-connector Links a cable to a device Either a BNC or F connector fit into it DB-9 (RS-232) Recommended Standard 232 An industry standard since 1969 A serial connector used for modems, printers, early mice, etc Now used as a configuration port 66 block Legacy patch panel for voice-only connections A cross-connection device that connects wires to other devices 25-pair cables are used here 110 block Wire-to-wire patch panel Supports data and voice transmissions @ 1 Gbps on CAT 6 cables No intermediate interface required Many wires are punched down into this Supports 25 500 wires of the T568A or B standards 100-pair cables are use