TCP Alternative Backoff with ECN (ABE)
draft-ietf-tcpm-alternativebackoff-ecn-01

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Network Working Group                                         N. Khademi
Internet-Draft                                                  M. Welzl
Intended status: Experimental                         University of Oslo
Expires: November 5, 2017                                    G. Armitage
                                      Swinburne University of Technology
                                                            G. Fairhurst
                                                  University of Aberdeen
                                                             May 4, 2017

                 TCP Alternative Backoff with ECN (ABE)
               draft-ietf-tcpm-alternativebackoff-ecn-01

Abstract

   Recent Active Queue Management (AQM) mechanisms instantiate shallow
   buffers with burst tolerance to minimise the time that packets spend
   enqueued at a bottleneck.  However, shallow buffering can cause
   noticeable performance degradation when TCP is used over a network
   path with a large bandwidth-delay-product.  Traditional methods rely
   on detecting network congestion through reported loss of transport
   packets.  Explicit Congestion Notification (ECN) instead allows a
   router to directly signal incipient congestion.  A sending endpoint
   can distinguish when congestion is signalled via ECN, rather than by
   packet loss.  An ECN signal indicates that an AQM mechanism has done
   its job, and therefore the bottleneck network queue is likely to be
   shallow.  This document therefore proposes an update to the TCP
   sender-side ECN reaction in congestion avoidance to reduce the
   FlightSize by a smaller amount than the congestion control
   algorithm's reaction to loss.  Future versions of this document will
   also describe a corresponding method for the Stream Control
   Transmission Protocol (SCTP).

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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Khademi, et al.         Expires November 5, 2017                [Page 1]
Internet-Draft                     ABE                          May 2017

   This Internet-Draft will expire on November 5, 2017.

Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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Table of Contents

   1.  Definitions . . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Specification . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Discussion  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     4.1.  Why Use ECN to Vary the Degree of Backoff?  . . . . . . .   4
     4.2.  Focus on ECN as Defined in RFC3168  . . . . . . . . . . .   5
     4.3.  Discussion: Choice of ABE Multiplier  . . . . . . . . . .   5
   5.  Status of the Update  . . . . . . . . . . . . . . . . . . . .   6
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   7
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   8.  Implementation Status . . . . . . . . . . . . . . . . . . . .   8
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   10. Revision Information  . . . . . . . . . . . . . . . . . . . .   8
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     11.1.  Normative References . . . . . . . . . . . . . . . . . .   9
     11.2.  Informative References . . . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Definitions

   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 RFC 2119 [RFC2119].

2.  Introduction

   Explicit Congestion Notification (ECN) [RFC3168] makes it possible