Re: [aqm] TCP ACK Suppression

Joe Touch <touch@isi.edu> Thu, 08 October 2015 21:15 UTC

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To: "LAUTENSCHLAEGER, Wolfram (Wolfram)" <wolfram.lautenschlaeger@alcatel-lucent.com>, Greg White <g.white@CableLabs.com>, "aqm@ietf.org" <aqm@ietf.org>
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From: Joe Touch <touch@isi.edu>
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Subject: Re: [aqm] TCP ACK Suppression
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On 10/7/2015 12:42 AM, LAUTENSCHLAEGER, Wolfram (Wolfram) wrote:
...
> Is this topic addressed in some RFC already?

It's a direct violation of RFC793, which expects one ACK for every two
segments:

4.2 Generating Acknowledgments

   The delayed ACK algorithm specified in [Bra89] SHOULD be used by a
   TCP receiver.  When used, a TCP receiver MUST NOT excessively delay
   acknowledgments.  Specifically, an ACK SHOULD be generated for at
   least every second full-sized segment, and MUST be generated within
   500 ms of the arrival of the first unacknowledged packet.

Joe