Re: [tcpm] I-D Action: draft-ietf-tcpm-prr-rfc6937bis-00.txt

"Scheffenegger, Richard" <> Mon, 08 February 2021 22:27 UTC

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From: "Scheffenegger, Richard" <>
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Date: Mon, 08 Feb 2021 23:27:17 +0100
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Subject: Re: [tcpm] I-D Action: draft-ietf-tcpm-prr-rfc6937bis-00.txt
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Hi Matt, Yuchung, Nandita,

The heuristic to switch between PRR-CRB and PRR-SSRB is only mentioned
in section 1 (intro to bis).

Perhaps the actual pseudocode and text in secion 4 (algo) should also be
expanded to contain this.

 From an implementers viewpoint, the paragraph about the heuristic (as
well as my conversation with Matt about this) left me wondering, if this
needs additional state, or how to achive this (e.g. tracking changes to
the SACK scoreboard - if an additional "hole" got accounted even when
snd.una advances, for example.

one nit: In the para for the definition of "SACKd", there is one
instance where the "SACK blocks" got changed to "sack blocks". Its the
only instance of lowercase SACK.

Best regards,

Am 14.01.2021 um 08:18 schrieb
> A New Internet-Draft is available from the on-line Internet-Drafts directories.
> This draft is a work item of the TCP Maintenance and Minor Extensions WG of the IETF.
>          Title           : Proportional Rate Reduction for TCP
>          Authors         : Matt Mathis
>                            Nandita Dukkipati
>                            Yuchung Cheng
> 	Filename        : draft-ietf-tcpm-prr-rfc6937bis-00.txt
> 	Pages           : 19
> 	Date            : 2021-01-13
> Abstract:
>     This document updates the Proportional Rate Reduction (PRR) algorithm
>     described as experimental in RFC 6937 to standards track.  PRR
>     potentially replaces the Fast Recovery and Rate-Halving algorithms.
>     All of these algorithms regulate the amount of data sent by TCP or
>     other transport protocol during loss recovery.  PRR more accurately
>     regulates the actual flight size through recovery such that at the
>     end of recovery it will be as close as possible to the ssthresh, as
>     determined by the congestion control algorithm.
> The IETF datatracker status page for this draft is:
> There are also htmlized versions available at:
> Please note that it may take a couple of minutes from the time of submission
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