EIGRP flap when manual router ID entered.

[Siddharam M]

Hi,

We had recently entered manual router id in our core cisco 7600 routers.

The router ID which we have entered manually was already selected by EIGRP dynamically.

But only in one of the router we have found that EIGRP has flapped when changing the router ID with log "EIGRP flap : route configuration changed".

We checked everything , we could only find the difference in IOS version.

The one which had flapped EIGRP had IOS version 12.2(33) and the one where we did not observe flap had IOS version 15.0(1).

We would like to know whether is there any bug in IOS or is it the limitation of the ios version.

Thanks in advance..

Siddu

[Peter Paluch]

Hi Siddu,

I was able to find a bug at https://tools.cisco.com/bugsearch/bug/CSCtf50970 that documents a reversed process: after issuing no eigrp router-id, the EIGRP adjacencies flapped even though the automatically chosen RID was the same as the previously configured value. It could be related to the issue you have experienced.

Best regards,
Peter

[Siddharam M]

Hi Peter,

Thanks for your reply. But in our case we are configuring the router-id command, not removing it.

can you pls confirm would this be same.

Regards...

Siddu

[Peter Paluch]

Hi Siddu,

You must understand that I am not a Cisco employee and I do not  have access to EIGRP source code as implemented in IOS. I can only infer things by looking at the obvious symptoms and looking into the bug database just like you.

I understand that you have observed a problem when doing things in opposite direction - when configuring the EIGRP RID manually. You are asking whether this bug covers this behavior as well. My best answer is: I do not know but there is at least a possibility that it does. Quite frankly, I am not sure whether it matters so much, as you already have seen that one IOS version exhibits this behavior while another IOS version doesn't.

Best regards,
Peter