RIP version 1
Routing Protocols and Concepts – Chapter 5
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
ITE PC v4.0
Chapter 1
1
Objectives
 D
esc
ri
be
th
e
f
u
n
c
ti
o
n
s,

c
h
a
r
ac
t
e
ri
s

 Describe how RIPv1 per
f
orms automatic
summarization.
 Configure, verify, and troubleshoot default routes
propagated in a routed network implementing RIPv1.
 Use recommended techniques to solve problems
related to RIPv1
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RIP Historical Impact
 RIP evolved from an earlier
p
rotocol
p
developed at Xerox, called Gateway
Information Protocol (GWINFO).
 With the development of Xerox Network
System (XNS) GWINFO evolved into
System

(XNS)
,
GWINFO

evolved

into


some

improvements
.
 Since then, RIP has been improved with
RIPv2 in 1994 and with RIPng in 1997.
IPv6 form of RIP called
RIPng (next generation) is
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RIPng

(next

generation)

is

now available
RIPv1
 RIP Characteristics
–A classful, Distance Vector
(DV) routing protocol
(DV)

routing


4
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
RIPv1
RIPv1
 RIP Message Format

RIP header
-
divided into 3 fields
RIP

header

divided

into

3

fields
–Command field
•REQUEST (1)- Request either a partial
or full table update from another RIP
router.
•RESPONSE (2) - A response to a
request.
–Version field
•
1or2
•

-
This

is

sent

out

on

startup

by

each

RIP

enabled interface
Requests all RIP enabled neighbors to send
-
Requests

all

RIP

enabled


y
into classes
-
Class A
Class

A
-Class B
CC
-
C
lass
C
 RIP is a classful routing
protocol
-Does not send subnet
masks in routing updates
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Common RIP confi
g
uration issues
g
RIP and IGRP:
 Classful network statements only
 IOS will take subnetted networks but will translate it into
the classful network for the running-config.
ITE PC v4.0


set

up

-No PCs attached to LANs
Uf5difftIP
-
U
se o
f

5

diff
eren
t

IP

subnets
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BiRIP1Cfi ti
B
as
i
c

configuration

prompt
-Prompt will look like R1(config-router)#
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Basic RIPv1 Configuration
Basic

RIPv1

Configuration
 S
p
ecif
y
in
g
Networks
pyg
–Use the network
command to:
-Enable RIP on all
interfaces that
belong to this
network
-
A

show

ip

protocols
-debug ip rip
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V ifi ti d T bl h ti
V
er
ifi
ca
ti
on an
d

T
rou
bl
es
h
oo
ti
ng

show ip protocols


Chapter 1
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p
and “show ip protocol”?
Verification and Troubleshooting
Verification

and

Troubleshooting
 Debug ip rip command
Used to display RIP routing updates as they are
-
Used

to

display

RIP

routing

updates

as

they


-
Example:
-
Example:

Router(config-router)#passive-interface interface-type interface-number
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Verification and Troubleshooting

Passive interfaces
Passive

interfaces
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Preventin
g
routin
g
u
p
dates throu
g
h an interface
ggp g

Route filters have no effect on link-state
advertisements or the link
state database
advertisements

or

the

link
-
state

database
.
(Tony) Route filtering could have negative
effect on the link-state routing protocol.

Using the
passive interface
command

Using

the

passive

interface
command


dynamically
.
Preventing routing updates
Preventing

routing

updates

through an interface

Again this is only half the
It will break the rip update
1

Again
,
this

is

only

half

the

story.
When you use “passive

bli
s
h
t
h
e
2
way
communication
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Automatic Summarization
Automatic

Summarization

Modified Topology

The original scenario has been
The

original

scenario

has

been

Cfi ti Dtil

C
on
fi
gura
ti
on
D
e
t
a
il
s
-To remove the RIP routing
th f ll i
process use
th
e
f
o
ll
ow
i
ng
command
Nti
N
o rou
t

network

to

another
.
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Automatic Summarization
Automatic

Summarization
Processing RIP Updates
 2 rules govern RIPv1 updates:
-If a routin
g
u
p
date and the interface it’s
gp
received on belong to the same
network then
The subnet mask of the
The

subnet

mask

Th
e c
l
ass
f
u
l
su
b
net mas
k
o
f
t
h
e
network is applied to the
network in the routing update.
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Automatic Summarization

Sending RIP Updates

Sending

RIP


Advantages

of

automatic

summarization:
-
The size of
-
The

size

of

routing updates is
reduced
-Single routes are
used to represent
multiple routes
which results in
faster lookup in the
faster

lookup

in

the