1.4 Routing Protocol
1.4.8 IGRP overview
IGRP is a distance vector routing protocol developed by Cisco. IGRP sends routing updates at 90-second intervals that advertise networks for a particular autonomous system.

The following are some key characteristics of IGRP.

Design emphasis:

  • Versatility to automatically handle indefinite, complex topologies.
  • Flexibility for segments having different bandwidth and delay characteristics.
  • Scalability to function in very large networks.

IGRP may use a combination of variables to determine a composite metric.

Variables IGRP uses include:

  • Bandwidth
  • Delay
  • Load
  • Reliability
  • Maximum transmission unit (MTU)