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Inside Gateway Routing Protocol (IGRP) is a distance vector inside gateway protocol (IGP) developed by Cisco. It’s utilized by routers to trade routing information inside an autonomous system.
IGRP is a proprietary protocol. IGRP was created partially to beat the constraints of RIP (most hop depend of solely 15, and a single routing metric) when used inside giant networks. IGRP helps a number of metrics for every route, together with bandwidth, delay, load, and reliability; to check two routes these metrics are mixed collectively right into a single metric, utilizing a components which will be adjusted by means of the usage of pre-set constants. By default, the IGRP composite metric is a sum of the section delays and the bottom section bandwidth. The utmost configurable hop depend of IGRP-routed packets is 255 (default 100), and routing updates are broadcast each 90 seconds (by default). IGRP makes use of protocol quantity 9 for communication.
IGRP is taken into account a classful routing protocol. As a result of the protocol has no subject for a subnet masks, the router assumes that each one subnetwork addresses inside the similar Class A, Class B, or Class C community have the identical subnet masks because the subnet masks configured for the interfaces in query. This contrasts with classless routing protocols that may use variable size subnet masks. Classful protocols have change into much less in style as they’re wasteful of IP tackle area.