BGP learned router flapping

[anil2109]

Hello,

I have a scenario where BGP neighbor to PE is stable but routes learned via this  got flapped .How to troubleshoot this .Should i check with Provider for the cause ?

[Richard Burts · Accepted solution]

We do not know much about your environment and there might be things that we do not know that could change our answer if we knew them. But based on what you describe so far, that you are running BGP with a provider, that the neighbor relationship is stable, but that routes learned from that neighbor are flapping then I would say that yes you should check with the provider about why the routes are flapping. Whatever is happening is likely within their network or is beyond their network and you would not have much visibility into that.

Can you tell us a bit about your provider and what they advertise to you? Is it just default route? Or is it a limited set of Internet routes? Or is it the complete Internet routing table? If it is complete Internet routes then I would expect quite a bit of volatility.

HTH

Rick

[anil2109]

Thanks for the reply.I agree that you understand it correctly.Customer wanted the reason for the route flap.So my question was should i check this  with service provider,or is there something i can do from my end before reaching the service provider.However we don't need to worry about the routes they are advertising ..One thing i can see in ip route table,only  routes learned from PE neighbor flapped,few routes from other neighbor is still stable.

So finally I  engaged service provider to check the cause for this . :)

[Richard Burts]

Thank you for the update. I am glad that my suggestion was helpful. Thank you for marking this question as solved. This will help other participants in the community to identify discussions which have helpful information. This community is an excellent place to ask questions and to learn about networking. I hope to see you continue to be active in the community.

HTH

Rick