CCNA Guide to Cisco Networking

1
CCNA Guide to Cisco Networking

• Chapter 9 Advanced Routing Protocols

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Objectives

• Describe classful and classless routing protocols
• Describe and configure RIPv2
• Describe and configure EIGRP
• Describe and configure OSPF
• Control routing traffic

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Classful And Classless Routing Protocols

• How the routing protocols handles subnets masks
  information
• Classful routing protocols
• RIPv1
• IGRP
• Major network boundaries (Class A, B, or C)
• Don not carry subnet mask information
• Cannot use or work with
• Discontiguous subnets
• VLSM

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Classful And Classless Routing Protocols
(continued)
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Classful And Classless Routing Protocols
(continued)
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Classful And Classless Routing Protocols
(continued)
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Classful And Classless Routing Protocols
(continued)
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Classful And Classless Routing Protocols
(continued)
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Classful And Classless Routing Protocols
(continued)
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Classful And Classless Routing Protocols
(continued)

• Classless routing protocols
• RIPv2
• EIGRP
• OSPF
• BGP
• Not restricted to Major network boundaries
• Carry subnet mask information
• Work with
• Discontiguous subnets
• VLSM

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Classful And Classless Routing Protocols
(continued)
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Classful And Classless Routing Protocols
(continued)
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Classful And Classless Routing Protocols
(continued)
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Classful And Classless Routing Protocols
(continued)
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Routing Information Protocol Version 2

• Metric
• Hops
• Max 15 hops
• 16th hop unreachable
• Carry subnet mask information
• Updates are multicast 224.0.0.9
• Ability to authenticate routing peers

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Routing Information Protocol Version 2 (continued)
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Routing Information Protocol Version 2 (continued)
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Routing Information Protocol Version 2 (continued)
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Routing Information Protocol Version 2 (continued)
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Routing Information Protocol Version 2 (continued)
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Routing Information Protocol Version 2 (continued)

• RIPv2 authentication steps
• Define a key chain
• Define keys in the key chain
• Enable authentication on the interface by
  specifying the key chain to be used
• Enable either clear text or MD5 authentication
• Manage the keys (optional key lifetimes)

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Routing Information Protocol Version 2 (continued)
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Routing Information Protocol Version 2 (continued)
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Routing Information Protocol Version 2 (continued)
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Enhanced Interior Gateway Routing Protocol

• Cisco proprietary protocol
• Hybrid protocol
• Features both distance-vector and link-state
  protocols
• Classless
• Not restricted to Major network boundaries
• Carry subnet mask information
• Work with
• Discontiguous subnets
• VLSM
• Route IP, IPX, and AppleTalk
• Protocol Dependent Modules (PDMs)

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Enhanced Interior Gateway Routing Protocol
(continued)

• Routing updates are
• Non-periodic
• Partial
• Bounded
• Authentication of peers
• Backwards compatible with IGRP
• Automatically share or redistribute between IGRP
  and EIGRP

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Enhanced Interior Gateway Routing Protocol
(continued)

• EIGRP components
• Protocol Dependent Modules
• Neighbor discovery and maintenance
• Reliable Transport Protocol
• Diffusing Update Algorithm (DUAL)
• Hello packets
• Multicast packets to 224.0.0.10
• Every 5 seconds on T1 or greater links
• Unicast packets
• Every 60 seconds on less than T1 speeds

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Enhanced Interior Gateway Routing Protocol
(continued)

• Hello packets (continued)
• Hold-down timer is 3 times Hello interval
• Peer routers do not need to have same settings
• Timers are configurable on a per-interface basis
• Hello packets use the Reliable Transport Protocol
  (RTP)
• EIGRP uses 5 packets types
• Hellos
• Acknowledgements
• Updates
• Queries
• Replies

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Enhanced Interior Gateway Routing Protocol
(continued)
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Enhanced Interior Gateway Routing Protocol
(continued)

• Diffusing Update Algorithm (DUAL) key terms
• Successor
• Feasible distance (FD)
• Reported distance (RD)
• Feasible successor
• Feasible condition
• Adjacency
• EIGRP tables
• Neighbor table
• Topology table
• Routing table

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Enhanced Interior Gateway Routing Protocol
(continued)
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Enhanced Interior Gateway Routing Protocol
(continued)
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Enhanced Interior Gateway Routing Protocol
(continued)
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Enhanced Interior Gateway Routing Protocol
(continued)
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Enhanced Interior Gateway Routing Protocol
(continued)
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Enhanced Interior Gateway Routing Protocol
(continued)
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EIGRP Configuration
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EIGRP Configuration (continued)
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EIGRP Configuration (continued)

• EIGRP peer routing authentication steps
• Define a key chain
• Define keys in the key chain
• Enable authentication on the interface by
  specifying the key chain to be used
• Manage the keys (optional key lifetimes)

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EIGRP Configuration (continued)
41
Open Shortest Path First

• OSPF
• Open standard
• Link-state routing protocol
• Classless routing and VLSM
• Authentication of routing peers
• Share a common view of the entire network
• Sends out link-state advertisements (LSA)
• LSAs are not periodic
• Sent only when a change occurs

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Open Shortest Path First (continued)

• Suited for large networks
• High CPU and memory demands
• OSPF creates the following
• Adjacency database
• Topology database
• Touting table

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Open Shortest Path First (continued)
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Open Shortest Path First (continued)

• OSPF Concepts
• Link
• Link-state
• Area
• Cost
• Adjacencies database
• Topological database
• Designated router
• Router election with router ID
• Backup designated router

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Open Shortest Path First (continued)
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Open Shortest Path First (continued)
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Open Shortest Path First (continued)
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OSPF Operation

• OPSP operation
• First Form adjacencies with neighbors
• Second Election of DR and BDR
• Third Flood LSAs
• Fourth Select best routes
• Dijkstras Shortest Path Algorithm
• Loop-free
• Best cost path
• CPU and Memory demands

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OSPF Operation (continued)
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Single-Area OSFP Configuration
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Single-Area OSFP Configuration (continued)
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Controlling Route Traffic

• passive-interface command
• RIP will receive updates not send
• RouterD(config) router rip
• RouterD(config-router) passive-interface s0
• EIGRP and OSPF will not send or receive updates

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Controlling Route Traffic (continued)
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Summary

• Large, complex internetworks using variable
  length subnet masks require routing protocols
  that can handle the task
• Several advanced routing protocols are in common
  use on networks today
• These protocols are classless and carry subnet
  mask information in their routing table updates

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Summary (continued)

• RIPv2 is a classless routing protocol built as an
  extension to RIPv1
• It supports modern networks use of VLSM and
  authentication
• In addition, it provides backward compatibility
  with RIPv1 when configured correctly
• Still, RIPv2 suffers from all the pitfalls of
  distance-vector routing protocols

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Summary (continued)

• EIGRP is a Cisco proprietary protocol designed to
  incorporate some of the features of link-state
  routing protocols
• It is, however, still a distance-vector routing
  protocol
• EIGRP does support classless routing
• Its use of neighbor, topological, and routing
  tables allows for quick convergence in the event
  of a link failure
• In fact, for each destination network, EIGRP
  keeps a successor or best route, and if possible
  a feasible successor or backup route

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Summary (continued)

• The open standards protocol OSPF is the
  link-state protocol of choice in many networks
  it supports VLSM, classless routing, and fast
  convergence
• In OSPF, each router uses the Shortest Path First
  Algorithm to determine the best loop-free path to
  each network
• Each router also uses an adjacency table,
  topological table, and routing table to pick the
  best route to a destination