Subject: Re: 'Slow-Start Restart after Idle' draft

From: Mark Allman <[email-masked]>
Date: Thu, 22 Oct 1998 16:22:48 -0400

> Host Requirements RFC (rfc1122) that describes Delayed Ack says
> that "there SHOULD be an ACK for at least every second segment".
> Note that its a SHOULD and not a MUST.  

Actually, I think it is a SHOULD in one place in 1122 and a MUST in
another.  In 2001.bis (draft-ietf-tcpimpl-cong-control-00.txt) we
unambiguously say that you SHOULD implement delayed ACKs and if you
do, you MUST ACK every second full-sized segment (with some hedges
as far as what a full-sized segment is, per Matt Mathis comments to
the list before the last IETF meeting).

allman

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http://gigahertz.lerc.nasa.gov/~mallman/

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From: "Eric A. Hall" <[email-masked]>
Date: Thu, 22 Oct 1998 13:48:37 -0700

[Ignorant mode on.]

> In 2001.bis (draft-ietf-tcpimpl-cong-control-00.txt) we unambiguously
> say that you SHOULD implement delayed ACKs and if you do, you MUST
> ACK every second full-sized segment

My Caldera 1.3 system here sends one ACK for every seven segments, with
no apparent loss in performance.

I take it the benefit of frequent ACKs is most pronounced when timing is
a problem. What is the benefit to increasing the ACK frequency if the
timing is solid?

-- 
Eric A. Hall                                            [email-masked]
+1-650-685-0557                                    http://www.ehsco.com