Proportional Rate Reduction for TCP
draft-ietf-tcpm-prr-rfc6937bis-01

Document Type Active Internet-Draft (tcpm WG)
Authors Matt Mathis  , Nandita Dukkipati  , Yuchung Cheng 
Last updated 2021-02-22
Replaces draft-mathis-tcpm-rfc6937bis
Stream Internet Engineering Task Force (IETF)
Intended RFC status (None)
Formats plain text pdf htmlized (tools) htmlized bibtex
Stream WG state WG Document (wg milestone: Aug 2021 - Submit RFC6937bis do... )
Document shepherd No shepherd assigned
IESG IESG state I-D Exists
Consensus Boilerplate Unknown
Telechat date
Responsible AD (None)
Send notices to (None)
TCP Maintenance Working Group                                  M. Mathis
Internet-Draft                                              N. Dukkipati
Obsoletes: 6937 (if approved)                                   Y. Cheng
Intended status: Standards Track                            Google, Inc.
Expires: 26 August 2021                                 22 February 2021

                  Proportional Rate Reduction for TCP
                   draft-ietf-tcpm-prr-rfc6937bis-01

Abstract

   This document updates the experimental Proportional Rate Reduction
   (PRR) algorithm, described 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 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.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 26 August 2021.

Copyright Notice

   Copyright (c) 2021 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components

Mathis, et al.           Expires 26 August 2021                 [Page 1]
Internet-Draft         Proportional Rate Reduction         February 2021

   extracted from this document must include Simplified BSD License text
   as described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Document and WG Information . . . . . . . . . . . . . . .   3
   2.  Background  . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Changes From RFC 6937 . . . . . . . . . . . . . . . . . . . .   5
   4.  Relationships to other standards  . . . . . . . . . . . . . .   6
   5.  Definitions . . . . . . . . . . . . . . . . . . . . . . . . .   7
   6.  Algorithms  . . . . . . . . . . . . . . . . . . . . . . . . .   8
   7.  Examples  . . . . . . . . . . . . . . . . . . . . . . . . . .   9
   8.  Properties  . . . . . . . . . . . . . . . . . . . . . . . . .  12
   9.  Adapting PRR to other transport protocols . . . . . . . . . .  14
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  14
   11. Security Considerations . . . . . . . . . . . . . . . . . . .  15
   12. Normative References  . . . . . . . . . . . . . . . . . . . .  15
   13. Informative References  . . . . . . . . . . . . . . . . . . .  15
   Appendix A.  Strong Packet Conservation Bound . . . . . . . . . .  17
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  18

1.  Introduction

   This document updates the Proportional Rate Reduction (PRR) algorithm
   described in [RFC6937] from experimental to standards track.  PRR
   accuracy regulates the amount of data sent during loss recovery, such
   that at the end of recovery the flight size will be as close as
   possible to the ssthresh, as determined by the congestion control
   algorithm.  PRR has been deployed in at least 3 major operating
   systems covering the vast majority of today's web traffic.

   The only change from RFC 6937 is the introduction of a new heuristic
   that replaces a manual configuration parameter.  There have been no
   changes to the behaviors of the algorithms or the previously
   published results.  The new heuristic only changes behaviors in
   corner cases that were not relevant prior to the Lost Retransmission
   Detection (LRD) algorithm which was not implemented until after RFC
   6937 was published.  This document also includes additional
   discussion about integration into other congestion control and
   recovery algorithms.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119]
Show full document text