On a Cisco router, enabling IGRP is similar to enabling RIP, except that you select IGRP as the protocol and add an autonomous system number.
For example :
RouterA(config)#router igrp 10 (10 is the AS number)
RouterA(config-router)#network 192.168.0.0
RouterA(config-router)#network 192.168.1.0
RouterA(config-router)#network 192.168.2.0
