BGP failover problem

[Sagar Purohit]

Hi

I am new to bgp please help me out troubleshooting this issue

My topology consists of 2 edge router one with evpn as primary and dmvpn as secondary. And have two 4500 core switches running ebgp between both the edge routers and ibgp between both the core switches.

both the core switches learn the routes from both the edge router.

Default route from dmvpn with local pref 50 and specific routes from evpn with local pref 100. (sh ip bgp )

Comming to the issue. Whenever evpn goes down, it should auto failover to the dmvpn but it is not happening.

Can you guys help me with what the issue can be? or what are the possibilities that I should check for

Thanks in Advance

Sagar

[blau grana]

Hi Sagar,

sample configs with topology would be nice, from information you provided we can only guess what is the issue.

Best Regards

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[milan.kulik]

Hi,

what do you exactly mean by "... it should auto failover to the dmvpn but it is not happening."

Don't the specific routes disappear from your 4500s BGP tables?

When you do traceroute to some remote site, does it follow the default route?

If yes, do the remote sites know your evpn is down, i.e., do they route back to you via dmvpn?

HTH.

Milan

[Sagar Purohit]

Specific routes disappear but the default route learnt form DMVPN doesn't get installed in the 4500 routing table.

[Shirshendu Nandi]

Chk for any other default route in 4500 do a sh ip route 0.0.0.0 in the router  when  both links are  up and when evpn down conditions .Also  do a sh ip bgp 0.0.0.0 in both cases  . Must be a better default route or prefix list filter causing rib failure.

[Ajay Raj]

Just check in your BGP table whether default route is installed with LP 50, if it is installed definitely failover should work. If not please share BGP config, BGP summary and BGP table outputs.