TCP Alternative Backoff with ECN (ABE)
draft-khademi-alternativebackoff-ecn-00

The information below is for an old version of the document
Document Type Active Internet-Draft (individual)
Last updated 2015-06-30
Replaced by draft-khademi-tsvwg-ecn-response, draft-khademi-tcpm-alternativebackoff-ecn
Stream (None)
Intended RFC status (None)
Formats plain text pdf html bibtex
Stream Stream state (No stream defined)
Consensus Boilerplate Unknown
RFC Editor Note (None)
IESG IESG state I-D Exists
Telechat date
Responsible AD (None)
Send notices to (None)
Network Working Group                                         N. Khademi
Internet-Draft                                                  M. Welzl
Updates: 3168 (if approved)                           University of Oslo
Intended status: Experimental                                G. Armitage
Expires: January 1, 2016                         Swinburne University of
                                                              Technology
                                                            G. Fairhurst
                                                  University of Aberdeen
                                                           June 30, 2015

                 TCP Alternative Backoff with ECN (ABE)
                draft-khademi-alternativebackoff-ecn-00

Abstract

   This memo updates the TCP sender-side reaction to a congestion
   notification received via Explicit Congestion Notification (ECN).
   The updated method is less conservative than the TCP reaction in
   response to loss.  The intention is to achieve good throughput when
   the queue at the bottleneck is smaller than the bandwidth-delay-
   product of the connection.  This is more likely when an Active Queue
   Management (AQM) mechanism has ECN-marked a packet than when a packet
   was lost.  Future versions of this document will discuss SCTP as well
   as other transports using ECN.

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 http://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 January 1, 2016.

Copyright Notice

   Copyright (c) 2015 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Khademi, et al.          Expires January 1, 2016                [Page 1]
Internet-Draft                     ABE                         June 2015

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://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 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  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Updating the Sender-side ECN Reaction . . . . . . . . . . . . . 3
   3.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 4
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 4
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 5
     6.1.  Normative References  . . . . . . . . . . . . . . . . . . . 5
     6.2.  Informative References  . . . . . . . . . . . . . . . . . . 5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 5

Khademi, et al.          Expires January 1, 2016                [Page 2]
Internet-Draft                     ABE                         June 2015

1.  Introduction

   Explicit Congestion Notification (ECN) is specified in [RFC3168].
   This allows a network device that uses Active Queue Management (AQM)
   to CE-mark rather than drop ECN-capable packets when incipient
   congestion is detected.

   When an ECN-capable transport is used over a path that supports ECN,
   it provides the opportunity for flows to improves their performance
   in the presence of incipient congestion [I-D.AQM-ECN-benefits].

   [RFC3168] not only specifies the router use of the ECN field, it also
   specifies a TCP procedure for using ECN.  This states that a TCP
   sender should treat the ECN indication of congestion in the same way
   as that of a non-ECN-Capable TCP flow experiencing loss, by halving
   the congestion window "cwnd" and by reducing the slow start threshold
   "ssthresh".  [RFC5681] stipulates that TCP congestion control sets
   "ssthresh" to max(FlightSize / 2, 2*SMSS) in response to packet loss.
   Consequently, a non-ECN enabled standard TCP flow using this reaction
   needs significant queue space: it can only fully utilize a bottleneck
   when the length of the link queue (or the AQM dropping threshold) is
   at least the bandwidth-delay product of the flow.  CUBIC can fully
Show full document text