The Some Congestion Experienced ECN Codepoint
draft-morton-taht-sce-00

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Transport Working Group                                        J. Morton
Internet-Draft                                           Bufferbloat.net
Updates: 3168, 8311 (if approved)                               D. Taeht
Intended status: Standards Track                                TekLibre
Expires: September 11, 2019                               March 10, 2019

             The Some Congestion Experienced ECN Codepoint
                        draft-morton-taht-sce-00

Abstract

   This memo reclassifies ECT(1) to be an early notification of
   congestion on ECT(0) marked packets, which can be used by AQM
   algorithms and transports as an earlier signal of congestion than CE.
   It is a simple, transparent, and backward compatible upgrade to
   existing IETF-approved AQMs, RFC3168, and nearly all congestion
   control algorithms.

Status of This Memo

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

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   This Internet-Draft will expire on September 11, 2019.

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   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Background  . . . . . . . . . . . . . . . . . . . . . . . . .   2
   4.  Some Congestion Experienced . . . . . . . . . . . . . . . . .   3
   5.  Examples of use . . . . . . . . . . . . . . . . . . . . . . .   5
     5.1.  Cubic . . . . . . . . . . . . . . . . . . . . . . . . . .   5
     5.2.  TCP receiver side handling  . . . . . . . . . . . . . . .   5
     5.3.  Other . . . . . . . . . . . . . . . . . . . . . . . . . .   5
   6.  Related Work  . . . . . . . . . . . . . . . . . . . . . . . .   5
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   6
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     10.1.  Normative References . . . . . . . . . . . . . . . . . .   6
     10.2.  Informative References . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Terminology

   The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
   SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this
   document, are to be interpreted as described in [RFC2119].

2.  Introduction

   This memo reclassifies ECT(1) to be an early notification of
   congestion on ECT(0) marked packets, which can be used by AQM
   algorithms and transports as an earlier signal of congestion than CE
   ("Congestion Experienced").

   This memo limits its scope to the redefinition of the ECT(1)
   codepoint as SCE, "Some Congestion Experienced", with a few brief
   illustrations of how it may be used.

3.  Background

   [RFC3168] defines the lower two bits of the (former) TOS byte in the
   IPv4/6 header as the ECN field.  This may take four values: Not-ECT,
   ECT(0), ECT(1) or CE.

   Binary Keyword References

   ------------------------------------------------------------

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    00     Not-ECT (Not ECN-Capable Transport)     [RFC 3168]
    01     ECT(1) (ECN-Capable Transport(1))       [RFC 3168]
    10     ECT(0) (ECN-Capable Transport(0))       [RFC 3168]
    11     CE (Congestion Experienced)             [RFC 3168]

   Research has shown that the ECT(1) codepoint goes essentially unused,
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