[185536] in North American Network Operators' Group
Re: BGP hold timer on IX LAN
daemon@ATHENA.MIT.EDU (Nick Hilliard)
Tue Oct 27 04:20:11 2015
X-Original-To: nanog@nanog.org
X-Envelope-To: nanog@nanog.org
To: "marcel.duregards@yahoo.fr" <marcel.duregards@yahoo.fr>,
"North American Network Operators' Group" <nanog@nanog.org>
From: Nick Hilliard <nick@foobar.org>
Date: Tue, 27 Oct 2015 09:20:05 +0100
In-Reply-To: <562F2855.3060603@yahoo.fr>
Errors-To: nanog-bounces@nanog.org
On 27/10/2015 08:31, marcel.duregards@yahoo.fr wrote:
> I'm asking because we see more and more peering partners which force the
> hold timer to a lower value, and when BGP negotiate the timer, the lowest
> hold timer is the winner.
You need to be careful with this. On larger IXPs, there will be a wide
variety of kit with different capabilities, which will usually work well in
most circumstances, but which may not have enough cpu power to handle edge
cases like e.g. ixp maintenance or flaps when you get large amounts of bgp
activity. A low bgp timer might be fine for, say an asr9k or an mx960 with
the latest RE/RSP, but would be actively harmful if one of your peers is
using an mx80 or a sup720.
Nick
