[87668] in North American Network Operators' Group
Re: metric 0 vs 'no metric at all'
daemon@ATHENA.MIT.EDU (Stephen J. Wilcox)
Tue Jan 3 10:28:19 2006
Date: Tue, 3 Jan 2006 15:27:43 +0000 (GMT)
From: "Stephen J. Wilcox" <steve@telecomplete.co.uk>
To: Alexander Koch <efraim@clues.de>
Cc: nanog@nanog.org
In-Reply-To: <20060103072143.GA14342@shekinah.ip.tiscali.net>
Errors-To: owner-nanog@merit.edu
On Tue, 3 Jan 2006, Alexander Koch wrote:
> I was wondering if someone had done any or some research on this before...
> basically I am not sure with all the many implementations of BGP and all the
> vendors if and what those will do when they see a metric of 0 and no metric. I
> am not an expert knowing the actual protocol's messages exchanged, but I see
> some routes with nothing in the metric field on the various show commands, and
> some have explicit '0' metric.
>
> I do not trust all the BGP implementations around, and we consider changing
> the default outbound, with MEDs of course still available on request.
i had this some time ago, cant remember where but i found some answers...
basically no metric is undefined, and can be handled either as all-zero or
all-ones or anything you want really
the best practice was to set med manually to ensure the expected behaviour
occurred.
Steve
