Interior Gateway Routing Protocol

Interior Gateway Routing Protocol (IGRP) is a proprietary distance-vector routing protocol invented by Cisco, used by routers to exchange routing data within an autonomous system.

IGRP was created to overcome the limitations of RIP(max hop count and single routing metric) when used within large networks. IGRP's metrics include bandwidth, load, delay, and relability. The maximum hop count of IGRP-routed packets is 255.

Its successor is EIGRP, a hybrid routing protocol that combines link-state and distance-vector routing.