[c-nsp] bgp keepalive/hold timers on ethernet links

[Rodney Dunn]

You have to debug it further to figure out where
the drops are happening.

ie: on the link, on the input queue (sh int), bgp debugs
    to see the keepalives, etc...

If you have many peers those times might be too aggressive.

You could bump up the input hold queue and the spd queue to
make sure you are not dropping them on ingress.

You may want to look at BFD support for the BGP sessions if
you wan this low of a timer.

Rodney

On Wed, Aug 31, 2005 at 07:54:01AM -0700, matthew zeier wrote:
> 
> I'm turing up a new directly connected peer that sits several L2 switches away 
> from me (long haul GigE).
> 
> me - MM fiber - switch - SM fiber - "something" - SM - switch - MM - peer
> 
> As a result, I'll never lose link if the long haul portion goes down and it's 
> unlikely that the 100ft MM run will ever fail.
> 
> BGP's default 60/180 timers are too long to go before dropping the peer.  The 
> PHB wanted 1 second keepalives and a 3 second hold timer.  However, as soon as 
> I started pulling in traffic (and only 50Mbps), I began frequently dropping 
> the the peer.
> 
> Aug 30 17:42:06.016 PDT: %BGP-5-ADJCHANGE: neighbor 216.x.253.233 Up
> Aug 30 17:49:40.612 PDT: %BGP-5-ADJCHANGE: neighbor 216.x.253.233 Down BGP 
> Notification sent
> Aug 30 17:49:40.612 PDT: %BGP-3-NOTIFICATION: sent to neighbor 216.x.253.233 
> 4/0 (hold time expired) 0 bytes
> Aug 30 17:50:21.024 PDT: %BGP-5-ADJCHANGE: neighbor 216.x.253.233 Up
> Aug 30 17:57:59.581 PDT: %BGP-5-ADJCHANGE: neighbor 216.x.253.233 Down BGP 
> Notification sent
> Aug 30 17:57:59.581 PDT: %BGP-3-NOTIFICATION: sent to neighbor 216.x.253.233 
> 4/0 (hold time expired) 0 bytes
> 
> The remote peer also logged the session closed because of:
> 
> Last reset 01:07:13, due to BGP Notification sent, hold time expired
> 
> While running a continuous ping I verified that the loop was still up while 
> bgp was coming down.
> 
> I'm guessing that these timers are too aggressive - anyone have any practical 
> suggestions on how to fix this?
> 
> 
> 
> --
> matthew zeier - "But if you only have love for your own race, Then you only
> leave space to discriminate, And to discriminate only generates hate." - BEP
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