ca_ex_s2m05_rip version 1.ppt [compatibility mode]

8/3/2019 CA_Ex_S2M05_RIP Version 1.Ppt [Compatibility Mode]

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Chapter 5: RIP version 1

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

Hc vin mng Bch Khoa - Website: www.bkacad.com 2

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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RIP Characteristics

1. A classful, Distance Vector (DV)routing protocol

2. Metric = hop count

3. Routes with a hop count > 15 are


unreachable (considers a metric of16 as infinity )

4. Updates are broadcast every 30seconds

5. Calculates metrics using the

Bellman Ford algorithm


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RIP Message Format



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RIP Message Format

RIP header - divided into 3 fields

1. Command field2. Version field

3. Must be zero


Route Entry - composed of 3 fields1. Address family identifier

2. IP address3. Metric


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RIPv1 Message



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RIP Operation

RIP uses 2 message types:

1. Request message Each RIP-configured interface sends

out a request message on startup,


requesting that all RIP neighborssend their complete routing tables.

2. Response message

A response message is sent back byRIP-enabled neighbors.


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RIPv1

a) b)


c)Triggered update


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RIPv1

RIP is a classful routing protocol1. Does not send subnet masks in routing

updates2. When update routing information, using:

1. The subnet mask confi ured on a local


interface2. or applies the default subnet mask

based on the address class.

3. RIPv1 networks cannot be discontiguousnor can they implement VLSM.


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Administrative Distance

Default AD=120.

When compared to other interiorgateway protocols, RIP is the


- . IS-IS, OSPF, IGRP, and EIGRP

all have lower default AD values.


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Basic RIPv1 Configuration



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Basic RIPv1 Configuration

Router(config)# router rip Router(config-router)# network A.B.C.D



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R1(config)#router rip (config-router)#network 192.168.1.0 (config-router)#network 192.168.2.0 (config-router)#network 172.16.1.0

R2(config)#router rip

(config-router)#network 192.168.3.0 (config-router)#network 192.168.2.0 (config-router)#network 172.16.2.0



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Specifying Networks



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Specifying Networks

Router(config-router)#networkdirectly-connected-classful-

network-address

Enables RIP on all interfaces that belong


to a spec c networ . ssoc ateinterfaces will now both send and receiveRIP updates.

Advertises the specified network in RIProuting updates sent to other routersevery 30 seconds.


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Specifying Networks

Typing interface IP addresses as the following:

Router(config-if)#router rip

Router(config-router)#network 1.1.1.1Router(config-router)#network 1.1.1.2

. . .

show running-config

router rip

network 1.0.0.0

network 3.0.0.0



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Verification and Troubleshooting



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show ip route



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show ip protocols



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show ip protocols

RIP routing is configured

The correct interfaces send andreceive RIP updates


e rou er a ver ses e correcnetworks RIP neighbors are sending updates Animation 5.3.2


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Animation 5.3.3

debug ip rip



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Passive interfaces

To prevent a router from sending updates through aninterface.

Example:

Router(config-router)#passive-interface FastEthernet 0/0



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Passive interfaces



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Remove RIP

To remove the RIP routing process use

the following commandRouter(config)#no router rip


o c ec e con gura on use efollowing commandRouter#show running-config


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Automatic Summarization



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Boundary Routers RIP automatically summarizes


Boundary routers summarize RIPsubnets from one major networkto another.


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Major network = Classful



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Processing RIP Updates

2 rules govern RIPv1 updates:

1. If a routing update and the interface itsreceived on belong to the samenetwork then the subnet mask of the


routing update

2. If a routing update and the interface itsreceived on belong to a different

network then the classful subnet maskof the network is applied to the networkin the routing update.

10 1 0 0/16


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Router 1Router 2

12.1.0.0/16

10.1.0.0/16

10.3.0.0/16

.1.2 .1

.2

.2

10.2.0.0/16

+ 10.1.0.0/16 is same major net as sourcing of update 10.2.0.0/16 ?

-Yes: are they have same subnet mask?

- Yes : advertise the subnet 10.1.0.0/16

+ 12.1.0.0 /16 is same major net as sourcing of update 10.2.0.0/16 ?

- No: Summarize to 12.0.0.0 to advertise

+ Is 12.0.0.0 same major net as receiving interface 10.2.0.0/16 ?

-No: do any of this major net exist in RT?

- No : Router 2 apply major net 12.0.0.0/8 to RT

+ 10.1.0.0 /16 same major net as receiving interface 10.2.0.0/16 ?

- Yes:Router 2 apply mask of receiving interface (/16) to subnet

Send update

Same major Summarize

to major

Same mask

Advertise update

N

N

Y

Y

Receive update

Same major Subnet in RT

Install route using

receiving maskinterface

N

N

Y

Y

Install major route


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Router 1Router 2

10.1.0.0/1610.2.0.0/16

.1.2

.1.2 172.16.0.0/16

+ 10.1.0.0/16 is same major net as sourcing of update 172.16.0.0/16 ?

-No:Summarize to 10.0.0.0 to advertise

+ Is 10.0.0.0 same major net as receiving interface 172.16.0.0/16 ?

-No: do any of this major net exist in RT known from interfaces

other than that which received the update?

Discontiguous network

Using debug ip rip to see update - Yes : Router 2 ignore the update

Static route:ip route network [ mask] { address | interface } [ distance] [ permanent ]

On Router 1:

ip route 10.2.0.0 255.255.0.0 172.16.0.1

On Router 2

ip route 10.1.0.0 255.255.0.0 172.16.0.2


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Processing RIP Updates



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Sending RIP Updates



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Advantages of Automatic Summarization


S


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Advantages of Automatic Summarization

RIP uses automatic summarization

to reduce the size of a routingtable.


Single routes are used torepresent multiple routes which

results in faster lookup in therouting table.


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Disadvantages of Automatic Summarization


Does not support discontiguous networks

Di d t f A t ti S i ti


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Disadvantages of Automatic Summarization

Discontiguous Topologies do notconverge with RIPv1


network addresses out interfacesthat do not belong to the

advertised route.


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Default Route and RIPv1


D f lt R t d RIP 1


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D f lt R t d RIP 1


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Packets that are not defined specifically in arouting table will go to the specifiedinterface for the default route

Exam le: Customer routers use default


routes to connect to an ISP router.

Router(config)# ip route 0.0.0.0 0.0.0.0{exit-interface | next-hop IP address}



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Propagating the Default Route inRIPv1:

Router(config-router)# default-informationoriginate


s comman s use o spec y athe router is to originate defaultinformation, by propagating the static

default route in RIP update.



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Gateway of last resort


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Gateway of last resort


Propogate the static default route


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Propogate the static default route

Gate(config)#

Ip route 0.0.0.0 0.0.0.0 serial0/1

Gate(config)#router rip

default-information originateOr

Gate(config)#router ripredistribute static


Other command


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Other command

Router# clear ip route * Delete all route entries in RT. Do

not effect to the directly connectedroutes.


Other command


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Other command


Other command


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Other command


Q/A


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Q/A

All routers are configured with valid interface addresses inthe indicated networks and are running RIPv1. Thenetwork is converged. Which routes are present in therouting tables?


Q/A


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Q/A

The Ethernet interface on Router2 goes down and theadministrator notices that the route is still valid in therouting table of Router1. How much longer will it take forRouter1 to mark the route invalid by setting the metric to

16? Hc vin mng Bch Khoa - Website: www.bkacad.com 56

Labs


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


Summary


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y

RIP characteristics include:

Classful, distance vector routing protocolMetric is Hop Count


subnetsUpdates every 30 seconds

Rip messages are encapsulated in a UDP

segment with source and destination ports of520

Summary: Commands used by RIP


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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

Rtr(config-router)#passive-interface fa0/0 Prevent RIP updates from going out an interface

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.ppt [compatibility mode]

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