[j-nsp] eBGP neighbor link failure detection

[Andy Litzinger]

Hi John,
 you might be spot on- graceful restart is configured for this peer and it
does look like my side is respecting it:
> show bgp neighbor
<snip>
Options: <Preference HoldTime AuthKey GracefulRestart LogUpDown PeerAS
Refresh>

I'll let you know what I find out

-andy


On Thu, Mar 13, 2014 at 7:10 PM, John Neiberger <jneiberger at gmail.com>wrote:

> 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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>
>