Configuring Routing Information Protocol in Cisco

Prerequisite: IP addressing

Routing Information Protocol (RIP) is a distance vector protocol, dependent on UDP, that uses hop count (max 16 hops) to calculate route cost, relying on Bellman-Ford Algorithm. It has two versions – version 1 (always classful) and version 2 (by default classful but can be made classless). RIP avoids routing loops by implementing split horizon and poison reverse methods, and using periodic routing updates (every 30 seconds). RIP v1 uses broadcast address 255.255.255.255 and RIP v2 uses multicast address 224.0.0.9 for sending routing updates. RIP works on the Network layer of the OSI model with an AD value of 120.

Here’s an example to demonstrate the configuration of RIP in Cisco using 2 routers and 2 LANs.

Setting Up:

• Open the Cisco packet tracer for the desktop.
• Select the following devices:

Device	CPT model name	Qty.
Router	PT-Router	2
Switch	PT-Switch	2
PC	PC	4

• Use the following cables for the respective connections:

Type of Connection	CPT Cable
Router-to-Router	Serial DTE
Switch-to-Router	Copper Straight-Through
PC-to-Switch	Copper Straight-Through

• Set up the following topology as shown in the image below:

• IP addressing table for the PCs:

Device	IPv4 address	Default Gateway	Subnet Mask
PC0	192.168.20.2	192.168.20.1	255.255.255.0
PC1	192.168.20.3
PC2	192.168.21.2	192.168.21.1
PC3	192.168.21.3

• To assign an IP address to a PC, click on the PC and then, go to the Desktop tab
• Assigning of IP can be done through IP Configuration

Example:

            Syntax: ipconfig <ip address> <subnet mask> <default gateway>

Example:

• IP addressing table for the router interfaces:

Device	Interface	IPv4 address	Subnet Mask
Router0	FastEthernet0/0	192.168.20.1	255.255.255.0
	Serial2/0	10.0.0.1	255.0.0.0
Router1	FastEthernet0/0	192.168.21.1	255.255.255.0
	Serial2/0	10.0.0.2	255.0.0.0

• To assign an IP address to a router interface, click on the router.
• Assigning of IPs can be done in ‘Config’ tab:

Example:

Implementation:

After all the IP addresses have been assigned, we can start configuring the routes according to the Routing Information Protocol on the routers. The assigning of RIP routes to the router can be done according to the following procedure:

• Clicking on Router0, go to CLI tab.
• Enter the ‘config-router mode’ for RIP using the following commands:

Router>enable
Router#configure terminal
Enter configuration commands,
one per line.  End with CNTL/Z.
Router(config)#router rip 
Router(config-router)#

• Then, assign the RIP routes to the respective routers using the syntax shown below:

Syntax: network <network id>
This has to be done for all the networks
 that are directly connected to the Router.

Example for Router0:

• Repeat the same process for Router1 with respective RIP routes.

Verification:

The implementation can be verified in:

• Real-time mode: By pinging the IP address of any PC from a particular PC (say PC0 to PC2)
• Go to the ‘Command Prompt’ in the ‘Desktop’ tab of PC0.
• Then follow the given syntax:

Syntax: ping <IP address of the target PC>
In this case: ping 192.168.21.2

• You may get replies similar to the image shown below. This verifies that the connection is working fine.

Simulation mode: 

• By running the simulation for the ICMP packet exchange.
• Click on the ‘Event List tab and select Show All/None
• Then, click on ‘Edit Filters’.
• Go to the ‘IPv4’ tab and select ICMP
• Select a PC, go to ‘Command Prompt’, enter a ping command, and close the window.