Re: [Idr] TCP & BGP: Some don't send terminate BGP when holdtimer expired, because TCP recv window is 0

Job Snijders <job@sobornost.net> Wed, 16 December 2020 19:39 UTC

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Date: Wed, 16 Dec 2020 19:35:56 +0000
From: Job Snijders <job@sobornost.net>
To: "Jakob Heitz (jheitz)" <jheitz=40cisco.com@dmarc.ietf.org>
Cc: Claudio Jeker <cjeker@diehard.n-r-g.com>, "idr@ietf.org" <idr@ietf.org>
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Subject: Re: [Idr] TCP & BGP: Some don't send terminate BGP when holdtimer expired, because TCP recv window is 0
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Jumping in to pick a nit about perceived asymmetry and practical
reality.

On Wed, Dec 16, 2020 at 06:50:51PM +0000, Jakob Heitz (jheitz) wrote:
> There is no evidence of any problem with its received routes, only
> with the routes it sent to the stuck peer. 

* The routes received from the stuck peer might block a healthier route from being used

* The routes to be sent towards the stuck peer might contain routing information for healthier routes for destinations the stuck peer is advertising.

Both the local node and the stuck peer are operating on stale routing
information. Even though the signalling observably is stuck in 'only
one' direction, the staleness applies to both directions because BGP
nodes converge together: a problem in 1 direction is a problem for both
directions, for both nodes.

Kind regards,

Job