What

Similar to RIP
Distance vector routing protocol
Composite metric based on bandwidth, delay, reliability and MTU

Why

More detailed metrics than RIP
Supports larger networks (up to 255 hops instead of 15)

Concepts

• Distance Vector Protocol
  • Each router knows the distance (metric) and next-hop to destinations
• Autonomous Systems, NOT THE SAME AS IN BGP
  • IGRP can be split into sections, stupidly also called ASes
  • Routers need to be in the same AS to exchange routes

Election

No election

How

Works the same as RIP, except it sends update very 90 seconds instead of 30