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DISTANCEDISTANCE

VECTORVECTOR

ROUTINGROUTING

TS, PHẠM VĂN TÍNHTS, PHẠM VĂN TÍNH

PART11PART11

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ObjectiveObjective

Describe how routing loops can occur in distance vector routing

Describe several methods used by distance vector routing protocols to ensure that routing information is accurate

Configure RIP Use the ip classless command Troubleshoot RIP Configure RIP for load balancing Configure static routes for RIP Verify RIP Configure IGRP Verify IGRP operation Troubleshoot IGRP

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Distance Vector ConceptsDistance Vector Concepts

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Distance Vector Network DiscoveryDistance Vector Network Discovery

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Distance vector topology changeDistance vector topology change

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Distance vector routing loopDistance vector routing loop

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Problem : Counting to InfinityProblem : Counting to Infinity

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Solution: Defining a maximum countSolution: Defining a maximum count

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Solution: Split HorizonSolution: Split Horizon

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Solution : Holddown Timers Solution : Holddown Timers

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RRoutingouting I Informationnformation P Protocolrotocol

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RIPRIP

It is a distance-vector routing protocol.

Hop count is used as the metric for path selection.

If the hop count is greater than 15, the packet will be discarded.

By default, routing updates are broadcast every 30 seconds.

RIP implements split horizon and holddown mechanisms to prevent incorrect routing information from being propagated (Loop)

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Configuring RIPConfiguring RIP

BHM(config)# router rip – Selects RIP as the routing protocol

BHM(config-router)# network 10.0.0.0BHM(config-router)# network 192.168.13.0 – Specifies a directly connected networks

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Common RIP configuration issuesCommon RIP configuration issues

To reduce routing loops and counting to infinity, RIP uses the following techniques:Count-to-infinity Split horizon Holddown counters Triggered updates

• GAD(config-if)#no ip split-horizon• Router(config-router)#timers basic update

invalid holddown flush• GAD(config-router)#update-timer seconds• GAD(config-router)#passive-interface s0/0

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Verifying RIP configurationVerifying RIP configuration

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Verifying RIP configurationVerifying RIP configuration

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Verifying RIP configurationVerifying RIP configuration

BHM(config)# show ip route

BHM(config)# show ip protocols

BHM(config)# show running-config

BHM(config)# show interface s0/0

BHM(config)# show ip interface s0/0

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Troubleshooting RIP update issuesTroubleshooting RIP update issues

BHM(config)# debug ip rip

Other commands to troubleshoot RIP:show ip rip database

show ip protocols {summary}

show ip route

debug ip rip {events}

show ip interface brief

Debug ip rip

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Preventing routing updates through an Preventing routing updates through an interfaceinterface

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Integrating static routes with RIPIntegrating static routes with RIP

• GAD(config-router)# redistribute static

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IInterior nterior GGatewayateway R Routingouting P Protocolrotocol

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IGRPIGRP

Metrics: - bandwidth - delay

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IGRP : Show ip routeIGRP : Show ip route

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Configuring IGRPConfiguring IGRP

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IGRP : TimersIGRP : Timers

Update timer : 90 s

Invalid timer : 270 s

Holddown timer : 280 s

Flush timer : 630 s

Multiple Routing Protocols : RIP - IGRP

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Verifying IGRP configurationVerifying IGRP configuration

show ip route

show interface interface

show running-config

show running-config interface interface

show ip protocols

debug ip igrp events

debug ip igrp transactions