ca ex s2m05 rip version 1

8/3/2019 CA Ex S2M05 RIP Version 1

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Please purchase a personal license.

CCNA Ex loration version 4.0


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Objectives

Describe the functions, characteristics, and operationof the RIPv1 protocol.

Configure a device for using RIPv1. Verify proper RIPv1 operation. Describe how RIPv1 erforms automatic

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summarization. Configure, verify, and troubleshoot default routes

propagated in a routed network implementing RIPv1.

Use recommended techniques to solve problemsrelated to RIPv1


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RIPv1: Distance Vector,



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RIP History



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RIPv1

RIP CharacteristicsA classful, Distance Vector (DV) routing protocol

Metric = hop count

Routes with a ho count > 15 are unreachable


Updates are broadcast every 30 seconds


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RIP Message Format

RIP header - dividedinto 3 fieldsCommand field

Version field


Must be zero Route Entry -

composed of 3 fields

Address family

identifier IP address

Metric


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RIPv1 Message



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RIP Operation

RIP uses 2 message types: Request message

Each RIP-configured interface sends out arequest message on startup,

requesting that all RIP neighbors send their


comp e e rou ng a es. Response message

A response message is sent back by RIP-enabled neighbors.


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RIPv1

a) b)


c)Triggered update


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RIPv1

IP addresses initially divided intoclasses:

Class A

Class B

Class C

RIP is a classful routing protocol


in routing updates a router either uses the

subnet mask configured on alocal interface, or applies thedefault subnet mask basedon the address class.

RIPv1 networks cannotbe discontiguous nor canthey implement VLSM.


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Administrative Distance

RIPs default administrativedistance is 120.

When compared to otherinterior gateway protocols, RIP

is the least-preferred routingprotocol. IS-IS, OSPF, IGRP,


default AD values.


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Basic RIPv1 Configuration



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A typical topologysuitable for use by RIPv1includes:


Three router set upNo PCs attached to

LANs

Use of 5 different IPsubnets


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Router RIPCommand To enable RIP enter:

Router rip at the global configuration promptPrompt will look like R1(config-router)#



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Specifying Networks


Use the networkcommand to: Router(config-router)#network directly-connected-

classful-network-address

Enables RIP on all interfaces that belong to a specific network.Associated interfaces will now both send and receive RIPupdates.

Advertises the specified network in RIP routing updates sent to

other routers every 30 seconds.


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Verification and Troubleshooting



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Verifying RIP: show ip route

To verify and troubleshootrouting

Use the followingcommands:

show ip route


show ip protocolsdebug ip rip


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Verifying RIP: show ip protocols

show ip protocols

command: RIP routing is

configured

The correct interfaces


send and receive RIPupdates

The router advertisesthe correct networks

RIP neighbors aresending updates

Animation 5.3.2


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Used to display RIP routing updates as they are happening . Animation 5.3.3

Verifying RIP: debug ip rip



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Passive interfaces

Used to prevent a router from sending updates through aninterface:

Example:Router(config-router)#passive-interfaceFastEthernet 0/0



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Passive interfaces



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Remove RIP


Configuration Details To remove the RIP routing process use the following

command

Router(config)#no router rip

To check the configuration use the following command

Router#show running-config


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Automatic Summarization



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Modified Topology The original scenario has been modified such that: Three classful networks are used:

172.30.0.0/16192.168.4.0/24192.168.5.0/24

The 172.30.0.0/16 network is subnetted into three subnets:172.30.1.0/24172.30.2.0/24172.30.3.0/24

The following devices are part of the 172.30.0.0/16 classful network address: All interfaces on R1

S0/0/0 and Fa0/0 on R2


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Boundary Routers RIP automatically summarizes classful networks

Boundary routers summarize RIP subnets from onemajor network to another.



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Processing RIP Updates

2 rules govern RIPv1 updates: If a routing update and the

interface its received on belongto the same network then thesubnet mask of the interface isa lied to the network in the


routing update If a routing update and the

interface its received on belongto a different network then theclassful subnet mask of the

network is applied to thenetwork in the routing update.


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Sending RIP Updates

RIP uses automatic summarization to reduce the sizeof a routing table.



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Advantages of Automatic Summarization

The size of routingupdates is reduced

Single routes are used torepresent multiple routeswhich results in faster


lookup in the routing table.


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Disadvantages of Automatic Summarization

Does not support discontiguous networks



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Disadvantages of Automatic Summarization

DiscontiguousTopologies do notconverge with RIPv1

A router will only


advertise majornetwork addresses outinterfaces that do notbelong to the

advertised route.


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Default Route and RIPv1



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Modified Topology: Scenario C Default routes

Packets that are not defined specifically in a routing table will go to

the specified interface for the default route Example: Customer routers use default routes to connect to an ISP

router.

Command used to configure a default route is

ip route 0.0.0.0 0.0.0.0 s0/0/1


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Propagating the Default Route in RIPv1 Default-information originatecommand

This command is used to specify that the router isto originate default information, by propagating thestatic default route in RIP update.



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Labs

1. Basic RIP Configuration2. Challenge RIP Configuration3. RIP Troubleshooting



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Summary

RIP characteristics include:Classful, distance vector routing protocol

Metric is Hop Count

Does not support VLSM or discontiguous subnets


p a es every secon s

Rip messages are encapsulated in a UDP segment withsource and destination ports of 520


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Summary: Commands used by RIP

Command Commands purpose

Rtr(config)#router rip Enables RIP routing process

Rtr(config-router)#network Associates a network with a RIP routing process

Rtr#debug ip rip used to view real time RIP routing updates


tr con g-router pass ve- nter ace a revent up ates rom go ng out an nter ace

Rtr(config-router)#default-information originate Used by RIP to propagate default routes

Rtr#show ip protocols Used to display timers used by RIP


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ca ex s2m05 rip version 1

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