The Local Area Network for Sunset will be working under one administration, so it will be working under one autonomous system. In order for routers to exchange routing information within a single autonomous system, these router routers will use Interior Gateway Protocols such us RIP, IGRP, OSPF, and EIGRP. However, as stated, Sunset will use IGRP as its Interior Gateway Protocol.
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:
The IGRP routing protocol uses a combination of variables to determine a composite metric. Variables of IGRP include bandwidth, delay, load, reliability, and maximum transmission unit (MTU).
In order for the Sunset routers to communicate their routing information, each router will be configured like:
Sunset_A(config)# router igrp 100
Sunset_A(config-router)# network 126.96.36.199
Sunset_A(config-router)# network 188.8.131.52
Sunset_A(config-router)# network 184.108.40.206
Sunset_A(config-router)# network 220.127.116.11
Sunset_B(config-router)# network 18.104.22.168
Sunset_B(config-router)# network 22.214.171.124
Sunset_B(config-router)# network 126.96.36.199
Sunset_B(config-router)# network 188.8.131.52
Sunset_C(config)# router igrp 100
Sunset_C(config-router)# network 184.108.40.206
Sunset_C(config-router)# network 220.127.116.11
Sunset_C(config-router)# network 18.104.22.168
The first line, which is the router command, tells that the routing protocol will be IGRP. The number, 100, is the autonomous system number, which identifies the IGRP router process that will share routing information.
The succeeding lines, the network command, specify any directly connected networks: a network number, not a subnet number or individual address. It allows the routing process to determine which interfaces will participate in the sending and receiving of routing updates.