Routing Information Protocol

Routing Information Protocol (RIP) is one of the most used protocols in network. It is used for routing packets between routers. The version using nowadays is called RIPv2, though there is a new version known as RIPng (ng stands for the Next Generation) which may be used mostly for IPv6. After getting active on a router, the router performs three basic functions which are as follows :

1. Router sending routing updates on the interfaces. 
2. The router listens and then processes incoming updates on that same interface.
3. The router advertises the connected subnets to the interface. 

The features of RIPv2 are as follows:

• It is password authenticated. 
• It creates the summary of routing table. 
• It can also be used for multicast address.
• It supports VLSM (Variable Length Subnet Mask) also.

Take three routers, three switches and three PC's. Connect the router with each other on there serial interface 2/0 and 3/0 using a serial cable. Then Connect each PC with a switch and each switch with the router on the interfaces 0/0 and 1/0 using a straight cable as shown below.

For configuration, we need to use router rip command on config mode and also choose version 2 for RIP. Following are the IP's and gateways we need to assign to PC's.

Now assign IP's to those interface which you will use as gateways . the IP's to be assign to router ethernet interfaces and serial interfaces.

In Router 0
fa 0/0 192.168.3.1
se 2/0 192.168.9.2
se 3/0 192.168.10.2

In Router 1
fa 0/0 192.168.5.1
se 2/0 192.168.9.1
se 3/0 192.168.11.2

In Router 2
fa 0/0 192.168.7.1
se 2/0 192.168.10.1
se 3/0 192.168.11.1

Following is the configuration for RIPv2

On Router 0
router(config)# router rip
router(config)# version 2

router(config)# network 192.168.3.0
router(config)# network 192.168.9.0
router(config)# network 192.168.10.0

On Router 1
router(config)# router rip
router(config)# version 2

router(config)# network 192.168.5.0
router(config)# network 192.168.9.0
router(config)# network 192.168.11.0

On Router 2
router(config)# router rip
router(config)# version 2

router(config)# network 192.168.7.0
router(config)# network 192.168.10.0
router(config)# network 192.168.11.0

Now if you ping pc1 to pc0 or pc2, you will get the reply :

To see the the routing table just write the command "show ip route", you will see the table as shown below

The lines which are starting with the symbol R shows the RIP connected routes.