Re: [tcpm] [Fwd: New Version Notification for draft-gomez-tcpm-ack-pull-00.txt]

"Scharf, Michael" <Michael.Scharf@hs-esslingen.de> Wed, 17 July 2019 12:45 UTC

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From: "Scharf, Michael" <Michael.Scharf@hs-esslingen.de>
To: Carsten Bormann <cabo@tzi.org>, Yoshifumi Nishida <nsd.ietf@gmail.com>
CC: "jon.crowcroft@cl.cam.ac.uk" <jon.crowcroft@cl.cam.ac.uk>, "tcpm@ietf.org Extensions" <tcpm@ietf.org>
Thread-Topic: [tcpm] [Fwd: New Version Notification for draft-gomez-tcpm-ack-pull-00.txt]
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Date: Wed, 17 Jul 2019 12:44:55 +0000
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Subject: Re: [tcpm] [Fwd: New Version Notification for draft-gomez-tcpm-ack-pull-00.txt]
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Is my understanding correct that this could be formalized as follows:

  A TCP MAY not delay ACKs for data segments with the PSH flag.

If that was the intention, I believe that the wording of RFC 1122 (and draft-ietf-tcpm-rfc793bis) would allow such a receiver-side heuristic already. Delayed ACKs are a SHOULD in RFC 1122 and the exact logic is not specified. Thus, taking the PSH flag into account inside a receiver-side delayed ACK heuristic may not even be a change of the TCP semantics…

Michael


Von: Carsten Bormann<mailto:cabo@tzi.org>
Gesendet: Mittwoch, 17. Juli 2019 09:56
An: Yoshifumi Nishida<mailto:nsd.ietf@gmail.com>
Cc: jon.crowcroft@cl.cam.ac.uk<mailto:jon.crowcroft@cl.cam.ac.uk>; tcpm@ietf.org Extensions<mailto:tcpm@ietf.org>
Betreff: Re: [tcpm] [Fwd: New Version Notification for draft-gomez-tcpm-ack-pull-00.txt]

On Jul 17, 2019, at 08:58, Yoshifumi Nishida <nsd.ietf@gmail.com>; wrote:
>
>  using a reserved flag is a bit expensive

The option could simply redefine existing PSH as having the AKP semantics.
(And possibly all packets having what used to be the PSH semantics.)
They are close enough anyway…

Grüße, Carsten

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