[j-nsp] eBGP neighbor link failure detection

[John Neiberger]

I've only seen something like this once and it was a graceful restart
issue....er...."feature" on a Cisco router, so I doubt it's the same
problem here. In that situation, the router waited for a graceful restart
timer to expire before it would clear out the routes, and it was doing this
despite the fact that it had never received a signal that the other side
was doing a graceful restart.

It seems unlikely that you'd be seeing the same type of problem, but the
symptoms sound very similar.

John


On Thu, Mar 13, 2014 at 3:38 PM, Andy Litzinger <
andy.litzinger.lists at gmail.com> wrote:

> One of my providers (and eBGP neighbor) recently had a hardware failure
> which caused the port that connects our two routers to go down.  My router
> did detect the link failure and BGP pretty much immediately transitioned to
> an Idle state.  my side is a Juniper MX80  running 11.4, their side I
> believe is a Cisco 6509.
>
> what surprised me is that it looks like routes toward that provider were
> not immediately removed from my routing table.  Instead i see evidence of
> blackholing for almost 3 minutes.  Is this normal behavior?  is the
> behavior configurable? I thought it might be related to the BGP holdtime,
> but that appears to be set for 30 seconds.
>
>   I see that cisco has a feature called 'fast-external-fallover' that
> bypasses the hold-down timer.  Is there an equivalent in JunOS?  what is
> the Juniper best practice to handle link failure between eBGP neighbors?
>
> thanks!
>  -andy
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