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

Enke Chen <enchen@paloaltonetworks.com> Thu, 17 December 2020 21:02 UTC

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From: Enke Chen <enchen@paloaltonetworks.com>
Date: Thu, 17 Dec 2020 13:02:14 -0800
Message-ID: <CANJ8pZ-WMDotkQvhN-NuP7ivZkPRR-9S2KJSar=6463U0VKkow@mail.gmail.com>
To: "Jakob Heitz (jheitz)" <jheitz@cisco.com>
Cc: "idr@ietf. org" <idr@ietf.org>, Enke Chen <enchen@paloaltonetworks.com>
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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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Hi, Jakob:

The BGP keepalive locally generated would become "pending data", and would
trigger the TCP probe, and the then TCP_USER_TIMEOUT mechanism.

If one is paranoid that the BGP keepalive may not be generated locally,
then use the TCP_KEEPAVLIE option together with the TCP_USER_TIMEROUT
option. That would be more robust.

Thanks.  -- Enke

--------------------

"Jakob Heitz (jheitz)" <jheitz@cisco.com> Thu, 17 December 2020 20:53 UTCShow
header <https://mailarchive.ietf.org/arch/browse/idr/#>

TCP_USER_TIMEOUT times the peer's ACK.
That's only half the problem.
The other half is the zero window.
When the peer is advertising zero window, everything is acked. no?

Regards,
Jakob.