Interior Gateway Routing Protocol

IGRP (Interior Gateway Routing Protocol) is the network protocol that was originally developed by Cisco Systems. Thus it is considered as the proprietary of Cisco. It was formed to operate on autonomous machines.

The Interior Gateway Routing Protocol (IGRP) is the distance-vector routing protocol. It denotes that every router transmits all or a part of its routing table in the routing messages updates at constant intervals to the routers in the neighborhood. A router is capable to chose the best available path between the source and the destination. Thus each of the such paths comprises multiple links, so the computer machine needs a system to make comparison amongst the links so as to locate the best possible path.  

The Interior Gateway Routing Protocol uses the five ways to ascertain the best path. These are the Link Speed, Packet Size, Delay, Loading and Reliability.

For each of these metrics, the network administrators may set the weighting factors.