Interior Gateway Routing Protocol
IGRP Features and Operation
IGRP has several features included in the algorithm--these features and a
brief description can be found below in Table 6.1. Most of these features
were added to make IGRP more stable, and a few were created to deal with
routing updates and make network convergence happen faster.
IGRP is a classful protocol, which means it doesn't include any subnet
information about the network with route information.
Classful protocols are discussed in Chapter 2.
IGRP recognizes three types of routes:
Networks directly connected to a router interface.
T A B L E 6 . 1
The user can configure metrics involved
in the algorithm responsible for
calculating route information.
Updates are sent out prior to the default
time setting. This occurs when the
metrics for a route change.
Poison reverse updates
Implemented to prevent routing loops,
these updates place a route in
Hold-down means that the router
won't accept any new route information
on a given route for a certain period
Unequal-cost load balancing
Allows packets to be shared or
distributed across multiple paths.
Copyright ©2001 SYBEX , Inc., Alameda, CA