RIPV2 manual summarization

[Phil Bradley]

I am using RIPv2 no auto summary and then manually summarizing on specific interfaces. It appears that the manual summarization on one interface is  overriding the manual summarization on a different interface. This may be by design but here is what I have on each interface:

Router 1

SVI10

ip summary-address rip 10.0.0.0 255.252.0.0

SVI11

ip summary-address rip 10.0.0.0 255.248.0.0

Before I entered the summary address on SVI11, the router was advertising 10.0.0.0/14 out of the SVI10 interface. After entering the manual summarization on SV11, the SVI10 interface started summarizing 10.0.0.0/13. The way I understand manual summarization is that this is per interface. Why does SVI11 summary override the other interface SVI10 summary?

[Jon Marshall]

Phil

What does the network look like ?

Where are you seeing the effects of the summarisation ie. on what device ?

Jon

[Phil Bradley]

ASA ----- 3750-1 (x.x.x.1) ------- (x.x.x.2) 3750-2 ----- ASA

The 3750-1 has the network 10.0.0.0/14.

The  3750-2 has the network 10.4.0.0/14

IP summary-address rip 10.0.0.0/14 on the 3750-1 .1 interface

IP summary-address rip 10.4.0.0/14 on the 3750-2 .2 interface

IP summary-address rip 10.0.0.0/13 on the 3750-1 to ASA interface 

The last command is what creates the 10.0.0.0/13 summary on the 3750-1.1 interface. Even though I only have 10.0.0.0/14 entered on this interface, it appears that the /13 trumps this. It looks like ip summary only stores the most summarized address in the rip database which overrides the summary on the 3750-1.1 interface.

[Jose Jara]

Hi Phil,

yes, it´s how RIPv2 works. When you apply summarization it´s subject to a subnet of this aggregate being in the RIP database.

Best Regards,

Jose.

[Phil Bradley]

I was hoping this was something that I was doing wrong or a bug. This means that I will need to manually summarize two routes instead of one from the 3750-1 to ASA.

interface 3750-1 to ASA

ip summary-address rip 10.0.0.0 255.252.0.0

ip summary-address rip 10.4.0.0 255.252.0.0

Then on the interface between the 3750's

ip summary-address rip 10.0.0.0 255.252.0.0

This works, but without the ability to summarize 10.0.0.0 255.248.0.0 on the 3750-1 to ASA interface.