RIP/IGRP VLSM question

Jun 27, 2006 1 Replies

Hi All,



Was wondering if anyone could help me on a VLSM question I have.



Suppose I have a network of 5 routers.



R1-R2-R3-R4-R5



Router1: f0/1: 172.16.70.17/28 s01: 172.16.80.2/24



Router2: s0/1: 172.16.80.1/24 s0/0: 172.16.20.1/24



Router3: s0/1: 172.16.20.2/24 s0/0: 172.16.40.1/24



Router4: s0/1: 172.16.50.1/24 s0/0: 172.16.60.1/24



Router5: s0/1: 172.16.60.2/24 f0/0: 172.16.70.1/28



Each router is running RIPv1 and advertising its local network using classful addresses, e.g. Router1 config would be



router rip network 172.16.0.0



The ethernet interface on R5 (172.16.70.1/28) to the ethernet interface on R1 (172.16.70.17/28). The classful address within the network is the same, so it's not a discontigious one, but there are different subnet masks in use (/24 and /28). I've tried this on a router simulator and it works, but I'd just like to be sure.



I understand that RIP and IGRP don't work with VLSM's, but is this only if there are two different classful addresses?



Many thanks in advance



Hi Dilan,

You are right RIPv1 dos not support VLSM because RIPv1 is a classfull protocol and VLSM needs a classless protocol like EIGRP, RIPv2 and OSPF. The router simulator is not correct, it should not work.

snipped-for-privacy@gmail.com wrote:

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