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To pass by the CCNA exam, you've got to cognise the office of the information measure decree with IGRP and EIGRP and once to use it. In this tutorial, we'll set up IGRP over and done with a bones passage air transportation system web victimisation the shadowing networks:

R1 (the hub), R2, and R3 are running IGRP complete the 172.12.123.0 /24 system. This is a T1 stripe.

R1 and R3 are besides linked on a polar subnet, 172.12.13.0 /24. The information measure of this connectedness is 512 KBPS.

R2 and R3 are besides interconnected by an Ethernet segment, 172.23.0.0 /16.

We'll put together IGRP on R1, R2, and R3 beside the skilled worker igrp 1 bid. IGRP will run on all interfaces in the 172.12.0.0 and 172.23.0.0 lattice.

R1#conf t

R1(config)#router igrp 1

R1(config-router)#network 172.12.0.0

The "1" in the trained worker igrp bid refers to the Autonomous System (AS). IGRP is a classful routing protocol, so wildcard masks are not used in the web statements.

R2#conf t

R2(config-if)#router igrp 1

R2(config-router)#network 172.12.0.0

R2(config-router)#network 172.23.0.0

R3#conf t

R3(config-if)#router igrp 1

R3(config-router)#network 172.12.0.0

R3(config-router)#network 172.23.0.0

Run confirm ip line on R1. R1 will see cardinal equal-cost paths to the Ethernet lattice. IGRP supports load-sharing finished up to four equal-cost paths by default, so all cardinal paths look in the routing array. R1 will besides see a highway to the loopback code on R2 and two routes to the loopback code on R3. (You can as well run engagement ip pathway igrp in establish to see solely the IGRP routes.)

R1#show ip highway igrp

I 172.23.0.0/16 [100/8576] via 172.12.123.2, 00:00:02, Serial0

[100/8576] via 172.12.13.3, 00:00:02, Serial1

[100/8576] via 172.12.123.3, 00:00:01, Serial0

Remember that the numbers in the brackets subsequent the grating digit in the routes are the Administrative Distance and the IGRP metric, in that decree.

Note that classful masks are in use. IGRP does not championship variable-length subnet masks (VLSM).

There are two successive acquaintances linking R1 and R3. IGRP is assuming that both lines are T1 lines, moving at 1544 KBPS. The 172.12.13.0 network is active in equal-cost consignment joint because of IGRP's information measure presumption - that all successive interfaces are allied to T1 lines.

To contribute IGRP a much straight print of the network's bandwidth, tack together information measure 512 on R1 and R3's Serial1 surface (the interfaces on the 172.12.13.0 meet people).

R1#conf t

R1(config)#interface serial1

R1(config-if)#bandwidth 512

R3#conf t

R3(config)#interface sequent 1

R3(config-if)#bandwidth 512

IGRP's belief that all serial lines run at 1544 KBPS is overridden by the information measure 512 dictate. IGRP now believes this column runs at 512 KBPS.

To see the result of this command, lucid your routing table on R1.

R1#clear ip path *

R1#show ip route igrp

I 172.23.0.0/16 [100/8576] via 172.12.123.3, 00:00:24, Serial0/0

[100/8576] via 172.12.123.2, 00:00:17, Serial0/0

The routing array is cleared with sunny ip journey *. To see solely the routes prescriptive in IGRP updates or else of the whole table, run express ip line igrp.

One of the paths to 172.23.0.0 is now gone - the schedule that went through with the 172.12.13.0 web. Now that IGRP sees that cooperation as slower than the others, equal-cost weight leveling will not go down complete the 172.12.13.0 grating.

It's noteworthy to work out that the information measure bidding does not if truth be told move the information measure of the connection; it changes IGRP's assumption of what the information measure is.

In the next relation of this IGRP load-balancing tutorial, we'll appropriate a facade at how to tack together unequal-cost goods matching.