Interior Gateway Routing Protocol (1)
Developed in the mid-1980s by Cisco Systems
Robust routing within a routing domain
many organizations replaced RIP by IGRP (RIP is limited to small networks)
IGRP works in IP networks and in CLNP (OSI ConnectionLess-Network Protocol) networks
Enhanced IGRP replaced IGRP in early 1990s
By default routing tables are updated every 90 sec
IGRP has a number of features (hold-downs, split-horizons,poison-reverse updates) designed to enhance IGRP stability