[98672] in North American Network Operators' Group
Re: inter-domain link recovery
daemon@ATHENA.MIT.EDU (Andy Davidson)
Wed Aug 15 06:19:55 2007
In-Reply-To: <200708151507025317576@ieee.org>
Cc: "nanog" <nanog@merit.edu>
From: Andy Davidson <andy@nosignal.org>
Date: Wed, 15 Aug 2007 11:09:24 +0100
To: Chengchen Hu <huc@ieee.org>
Errors-To: owner-nanog@merit.edu
On 15 Aug 2007, at 08:07, Chengchen Hu wrote:
> Just suppose no business fators (like multiple ASes belongs to a
> same ISP), is it always possible for BGP to automatically find an
> alternative path when failure occurs if exist one? If not, what may
> be the causes?
I think everyone here has already covered a lot of the bases to do
with your original question (i.e. 'Because kit might not be
configured to re-converge in an optimal way'), but if I can summarise
the question you are trying to answer as "how can we improve
convergence times", you might like to look at the notes that Nate
Kushman presented in Toronto this year
http://www.nanog.org/mtg-0702/kushman.html
Summary
Many studies show that when Internet links go up or down, the
dynamics of BGP may cause several minutes of packet loss. The loss
occurs even when multiple paths between the sender and receiver
domains exist, and is unwarranted given the high connectivity of the
Internet. Instead, we would like to ensure that Internet domains stay
connected as long as the underlying network is connected.
Andy
