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Silver

eBGP fast failover on failure of directly connected link ASR1001 to C4500x

 

I have a couple of internal eBGP links between ASR1001 and C4500X, configured via a port-channel. Following a failure of either the link or one of the network devices I want the eBGP session to drop rather than wait for the timers to expire.

I have appled bgp fast-external-failover under the router process, this didn't make any difference. The devices accept the command, it doesnt show up in the output of sh run, so either its on by default  or doesnt work as described.

 

After reading up I then found the fall-over command that I can append to a neighbour statement, so tried that, again following a directly connected link failure the eBGP session remans up, eventually timing out.

I then considered BFD which would be my choice in this type of setup, but it appears not to be supported on the port channel. I'm still investigating this.

Anyone got any other suggestions on how I can achieve a faster failover?

 

Andy

2 REPLIES

HelloI have found on certain

Hello

I have found on certain ios that you can configure BFD in bgp stanza but it doesn't allow interface configuration of the interval timers, and the same applies to eigrp/ospf regards show bfd commands.

 

That said bgp, even though its supports fast-fail over and BFD I was on the understanding this protocol was design no t for fast convergence but stability given it WAN capabilities.

 

However if BFD inst applicable you could always drop the timers.

rouer bgp xx
timers bgp 3 10

 

res

Paul.

 

Please don't forget to rate any posts that have been helpful. Thanks.
Silver

Thanks Paul, I applied those

Thanks Paul, I applied those timers, which reduced the convergence time.

 

Andy

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