IGRP (Interior Gateway Routing Protocol)

IGRP  (Interior Gateway Routing Protocol)

IGRP is an advanced distance vector routing protocol developed by Cisco in the mid-1980s. IGRP has several features that differentiate it from other distance vector routing protocols, such as RIP.

Characteristics of IGRP
Increased scalability - Improved for routing in larger size networks compared to networks that use RIP.

Sophisticated metric - IGRP uses a composite metric that provides significant route selection flexibility. Internetwork delay and bandwidth by default, and optionally reliability, and load are all factored into the routing decision. IGRP can be used to overcome RIP's 15-hop limit. IGRP has a default maximum hop count of 100 hops, configurable to a maximum of 255 hops.

Multiple paths - IGRP can maintain up to six nonequal paths between a network source and destination; the paths do not mandate equal costs like with RIP. Multiple paths can be used to increase available bandwidth or for route redundancy.







Procedure for Configuring IGRP



1.Define IGRP as the IP routing protocol using the router igrp autonomous-system global configuration command.

Router(config)#router igrp 100

2. Assign a major network number to which the router is directly connected using the network network-number router configuration command.

Router(config-router)#network 10.2.2.0

3. Configure load balancing using the variance multiplier router configuration command.

Router(config-router)#variance 1

4. Configure traffic distribution among IGRP load sharing routes using the traffic-share { balanced | min } router configuration command. Router(config- router)#traffic-share balanced

5.Display network information associated with the entire router using the show ip protocol privileged command.

Router#show ip protocols

6. Display the contents of the IP routing table using the show ip route privileged command.

Router#show ip route