Summary

IGRP is a distance vector routing protocol, like RIP. It was developed as a solution to some of the disadvantages of RIP, such as its hop-count limitation and frequent update timer. Unlike RIP, IGRP uses bandwidth and delay as the primary variables in calculating its metrics. Because IGRP and RIP are considered classical distance vector routing protocols, some of their behavior is exactly the same. As a result, neither IGRP nor RIP can support discontiguous networks and VLSM. However, one of the biggest advantages of IGRP over RIP is the capability to do unequal -cost load balancing.