[c-nsp] BGP timers

[Oliver Boehmer (oboehmer)]

Mark Tinka <> wrote on Tuesday, April 08, 2008 2:19 PM:

> On Tuesday 08 April 2008, Uddin, Tahir wrote:
> 
>> When connecting a CE to a PE, is there a minimum
>> recommended BGP hold down timer. I am currently using 90
>> seconds with both of my carriers but it is causing
>> applications to time out when there is a failure in one
>> of the carriers network or if a local loop goes down. One
>> of the carriers ruled out going down to 15 seconds, said
>> it was too low.
> 
> We are aggressive with timers within our own core. However,
> we keep it simple with customers unless there is a special
> request. At any rate, BGP will use the smaller of the two
> received in the open message during setup.
> 
> That said, if both sides are Cisco (and you have the
> requisite IOS release), you may consider testing the BGP
> Next Hop Address Tracking feature (enabled by default in
> supporting releases) and BGP Fast Peering Session
> Deactivation (configurable in supporting releases).

well, Fast Session Deactivation only helps you on non-directly connected
eBGP sessions (i.e. multihop), possibly along with an IGP (or static
routes with object tracking or something like this) to provide next-hop
reachability, so it's not that useful on "standard" directly-connected
eBGP sessions..
BFD should be evaluated instead..

	oli