[c-nsp] BGP Next hop tracking / 'hold down' route...

[Andrew Brant]

Fall-over combined with next hop tracking creates another distinct feature called selective address tracking:

The following commands are new or modified for this feature:
•bgp nexthop
•neighbor fall-over
http://www.cisco.com/en/US/docs/ios/12_4t/12_4t4/ht_bgpsn.html
>>    neighbor 192.168.25.7 fall-over route-map RTM-BGP-
>> FALLOVER


Cheers,
Andrew

CCIE 14715

Sent from my iPhone

On Jun 25, 2013, at 1:16 AM, Saku Ytti <saku at ytti.fi> wrote:

> On (2013-06-24 23:19 -0500), Andrew Brant wrote:
> 
>>    neighbor 192.168.25.7 fall-over route-map RTM-BGP-
>> FALLOVER
> Fall-over and next-hop tracking are two distinct features.
> With next-hop tracking, you simply invalidate the next-hops there by
> invalidating the routes and choosing next-best option.
> With fall-over you tear down whole session, this is usually undesirably
> large hammer, consider your IGP flap is very short, if you tore down the
> iBGP it might take minutes to recover.
> 
> But granted, if current version does not support selective next-hop
> resolution it seems like significantly better than nothing.
> 
> 
> -- 
>  ++ytti
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