RIP Exercises

Steps:

1.Configure IP addresses in the interfaces connecting R1 and R2

2.Create one loopback interface in each router and configure IP address

3.Enable RIP and advertise the network between the routers and the network of loopback

4.Check the routing table in both routers

Step 1: Configuring IP address in R1

R1#
R1#configure terminal 
R1(config)#interface fastEthernet 0/0
R1(config-if)#ip address 192.168.1.1 255.255.255.0
R1(config-if)#no shutdown 
R1(config-if)#exit
R1(config)#exit
R1#

Step 2: Creating loopback interface

R1#
R1#configure terminal 
R1(config)#interface loopback 1
R1(config-if)#ip address 10.0.0.1 255.0.0.0
R1(config-if)#exit
R1(config)#exit
R1#


R1#show ip interface brief 

Interface              IP-Address  	Status  Protocol
FastEthernet0/0        192.168.1.1  	up       up      
Loopback1              10.0.0.1 		up       up      
R1#


R1#show ip route

C    192.168.1.0/24 is directly connected, FastEthernet0/0
C    10.0.0.0/8 is directly connected, Loopback1


Step 3: Enable RIP and advertise networks

R1#
R1#configure terminal 
R1(config)#router rip
R1(config-router)#network 192.168.1.0 
R1(config-router)#network 10.0.0.0
R1(config-router)#exit
R1(config)#exit
R1#

Configuring IP address in R2

R2#
R2#configure terminal 
R2(config)#interface fastEthernet 0/0
R2(config-if)#ip address 192.168.1.2 255.255.255.0
R2(config-if)#no shutdown 
R2(config-if)#exit
R2(config)#exit
R2#

Creating loopback interface

R2#
R2#configure terminal 
R2(config)#interface loopback 1
R2(config-if)#ip address 20.0.0.1 255.0.0.0
R2(config-if)#exit
R2(config)#exit
R2#


R2#show ip interface brief 

Interface             IP-Address 	Status  Protocol
FastEthernet0/0       192.168.1.2   up       up      
Loopback1             20.0.0.1		up       up      
R2#


R2#show ip route

C    192.168.1.0/24 is directly connected, FastEthernet0/0
C    20.0.0.0/8 is directly connected, Loopback1

Enabling RIP and advertising networks

R2#
R2#configure terminal 
R2(config)#router rip
R2(config-router)#network 192.168.1.0 
R2(config-router)#network 20.0.0.0
R2(config-router)#exit
R2(config)#exit
R2#

R1#show ip route 

C    192.168.1.0/24 is directly connected, FastEthernet0/0
C    10.0.0.0/8 is directly connected, Loopback1
R    20.0.0.0/8 [120/1] via 192.168.1.2, 00:00:18, FastEthernet0/0

R2#show ip route

C    192.168.1.0/24 is directly connected, FastEthernet0/0
C    20.0.0.0/8 is directly connected, Loopback1
R    10.0.0.0/8 [120/1] via 192.168.1.1, 00:00:23, FastEthernet0/0

“show ip route” will show all types of routes (connected, static, rip, ospf etc) , if you are looking only for particular type try the following method

R2#show ip route rip
R    10.0.0.0/8 [120/1] via 192.168.1.1, 00:00:24, FastEthernet0/0

R2#show ip route connected
C    20.0.0.0/8 is directly connected, Loopback1
C    192.168.1.0/24 is directly connected, FastEthernet0/0

Understanding routing table entry:

R2#show ip route rip

R 10.0.0.0/8 [120/1] via 192.168.1.1, 00:00:24, FastEthernet0/0

In the above output,

“R” represents that this route is learned from RIP protocol

In [120/1] , 120 represents RIP’s administrative distance and 1 represent the metric to reach this network 10.0.0.0

The timer 00:00:24, shows that RIP received the last update 24 seconds back

FastEthernet0/0 is the exit interface to reach the network 10.0.0.0

When a network gets disconnected , RIP will send an update packet with metric set as 16 for that network, this is known route poison. On reply to this , neighbors will send the same information back to the first router ,which is called poison reverse.

To observe this you need to capture RIP packets using wireshark in PC1

Steps:

Start wireshark capture in PC1

Shutdown the loopback interface in R1

Observe the packets

R1#
R1#configure terminal 
R1(config)#interface loopback 1
R1(config-if)#shutdown 

Expiration timer:

When RIP stops receiving updates packets from a neighbor , it will wait for 180 secs and will mark the networks as unreachable (Metric will be changed to 16).

Garbage collection timer:

After expiration time, RIP will keep the networks for 60 more seconds in its database with metric value 16. During this period it will send updates to all neighbors in periodic intervals with metric set as 16 . Finally after 240 secs (180 + 60) RIP will remove that route from its routing table.

Steps:

1.Configure RIP and advertise networks as in the first exercise.

2.Verify that R2 is showing “10.0.0.0” in routing table

3.Disable RIP in R1

4.Repeat the command “show ip route rip” in R2 & observe timer and metric

Disabling RIP :

R1#
R1#configure terminal 
R1(config)#no router rip