Summarization with RIPV2

[berrug]

While working on my CCNA exam, I came across a Lab practicing which required me to use EIGRP on the routers. Then, I thought to myself ''Any chance I can use RIPV2 to summarize these routes?''.

I'm expected to summarize 192.168.1.0/2.0/3.0 networks on R1. I was not able to make this work using RIPV2 because I believe the summary route I used on R1 overlapped with 192.168.10.0 network. Is there anyway I can make this work by using RIPV2?

*The topology mentioned is below.

[luis_cordova]

Hi @berrug,

You could summarize the indicated networks manually and declare the summarized network in the RIPv2 configuration

192.168.0000 0001.0 = 192.168.1.0/24

192.168.0000 0010.0 = 192.168.2.0/24

192.168.0000 0011.0 = 192.168.3.0/24

The summarized network would be: 192.168.0.0/22

Regards

[Joseph W. Doherty]

192.168.0.0/22 would also encompass 192.168.0.0/24 (?) - if so, don't know if that's a concern

[berrug]

Thanks for the answers. My problem is when I use RIPv2 with manual summarization on R1, I can't ping the network 192.168.10.0 from any other network on the left side. Everything works fine when using Eigrp since I can use wildcard mask.

My Eigrp configuration on R1:

network 192.168.0.0  0.0.3.255

network 172.16.5.0

no auto-summary

I'm looking for a way to do this with RIPv2 so that any network on the left side (after getting summarized on R1) can ping the network 192.168.10.0. I don't know how to specify /22 while configuring Ripv2 as I can only type 192.168.0.0.

* I'm sorry about my broken English.

[luis_cordova · Accepted solution]

Hi @berrug,

Review this way to implement summarization and RIPv2:

router rip

version 2

redistribute static <- With this command I propagate the summarized network

network 172.16.0.0 <- Here I only declare the network 172.16.5.0

!

ip classless

ip route 192.168.0.0 255.255.252.0 Serial0/0/0

Regards

[jalejand · Accepted solution]

RIPv2 can only summarize in a Classful way, this means that you shouldn't be able to summarize 192.168.x.0 into 192.168.0.0 255.255.0.0 or 255.255.252.0 for a more exact matching summary.
Even though RFC 1918 says that class C addresses range is 192.168.0.0/16, CIDR classful mask for a class C is 255.255.255.0 = /24.

On a different approach, instead of using 192.168.1.0/2.0/3.0, you can summarize subnets that matches an entire class C range (/24), for example:

192.168.1.1/30
192.168.1.4/30
192.168.1.8/30
...
Summarized into 192.168.1.0/24, manual RIP summarization would allow this command.
Even though routes are overlapped, (thinking for a bit that summarization worked as expected on your scecnario) the router advertising 192.168.10.0/24 is advertising that exact same prefix while the other router is advertising a summary route. Traffic destined to 192.168.10.0/24 will use the longest prefix available that will be advertised by the originating router for 192.168.10.0/24, so it should not be any issue.

If you want, you can upload your packet tracer file so I can take a look at it.