Some Congestion Experienced in TCP
draft-grimes-tcpm-tcpsce-01

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Last updated 2019-11-04
Replaces draft-grimes-tcpmwg-tcpsce
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TCP Maintenance and Minor Extensions                         R.W. Grimes
Internet-Draft                                                  P. Heist
Intended status: Experimental                            4 November 2019
Expires: 7 May 2020

                   Some Congestion Experienced in TCP
                      draft-grimes-tcpm-tcpsce-01

Abstract

   This memo classifies a TCP code point ESCE ("Echo Some Congestion
   Experienced") for use in feedback of IP code point SCE ("Some
   Congestion Experienced").

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 7 May 2020.

Copyright Notice

   Copyright (c) 2019 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
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   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
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   provided without warranty as described in the Simplified BSD License.

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Table of Contents

   1.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Background  . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  TCP Receiver  . . . . . . . . . . . . . . . . . . . . . . . .   3
     4.1.  Single ACK implementation . . . . . . . . . . . . . . . .   3
     4.2.  Simple Delayed ACK implementation . . . . . . . . . . . .   3
     4.3.  Dithered Delayed ACK implementation . . . . . . . . . . .   3
     4.4.  Advanced ACK implementation . . . . . . . . . . . . . . .   4
     4.5.  ACK Thinning  . . . . . . . . . . . . . . . . . . . . . .   4
   5.  TCP Sender  . . . . . . . . . . . . . . . . . . . . . . . . .   4
   6.  Related Work  . . . . . . . . . . . . . . . . . . . . . . . .   4
     6.1.  More Accurate ECN Feedback in TCP . . . . . . . . . . . .   4
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   5
   10. Normative References  . . . . . . . . . . . . . . . . . . . .   5
   11. Informative References  . . . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   [RFC2119] and [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

2.  Introduction

   This memo requests a TCP header codepoint for use as ESCE.

   This memo limits its scope to the definition of the TCP codepoint
   ESCE, with a few brief illustrations of how it may be used.

   SCE provides early and proportional feedback to the CC (congestion
   control) algorithms for transport protocols, including but not
   limited to TCP.  The [sce-repo] is a Linux kernel modified to support
   SCE, including:

   *  Enhancements to Linux's [cake] (Common Applications Kept Enhanced)
      AQM to support SCE signaling

   *  Modifications to the TCP receive path to reflect SCE signals back
      to the sender

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   *  The addition of three new TCP CC algorithms that modify the
      originals to add SCE support: Reno-SCE, DCTCP-SCE and Cubic-SCE
      (work in progress as of this writing)

3.  Background

   [I-D.morton-tsvwg-sce] defines the IP SCE codepoint.

4.  TCP Receiver

   The mechanism defined to feed back SCE signals to the sender
   explicitly makes use of the ESCE ("Echo Some Congestion Experienced")
   code point in the TCP header.

4.1.  Single ACK implementation
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