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

Robert Raszuk <robert@raszuk.net> Sat, 12 December 2020 09:23 UTC

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From: Robert Raszuk <robert@raszuk.net>
Date: Sat, 12 Dec 2020 10:22:53 +0100
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To: Job Snijders <job@sobornost.net>
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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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I went back and reread the thread:

   https://mailarchive.ietf.org/arch/msg/idr/q0Sx5d3zZjfOmOQ4lO2OZAHh9Lc/

Shouldn't it be better if we first ask implementations to provide show
command/api to list all peers and min-max durations of TCP Window being 0
without actually doing any automagic RST/NOTIFICATION/FIN ?

This could allow to better understand which peers are getting behind in
their control plane and perhaps also allow to set the RST timer under such
conditions by operator? If he chooses this to be equal to HOLD TIME so be
it but I am not sure this would be universally an optimal choice.

Along the same lines we should perhaps also list per BGP peer number of
DUPLICATE ACKS, RETRANSMISSIONS etc ...

Are there implementations already deployed in DFZ allowing such data to be
displayed per each BGP peer ?

Thx,
Robert.