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Re-ECN: Adding Accountability for Causing Congestion to TCP/IP
draft-briscoe-conex-re-ecn-tcp-04

Document type: Active Internet-Draft (individual)
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Last updated: 2014-07-04
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Transport Area Working Group                             B. Briscoe, Ed.
Internet-Draft                                                A. Jacquet
Intended status: Historic                                             BT
Expires: January 5, 2015                                    T. Moncaster
                                                           Moncaster.com
                                                                A. Smith
                                                                      BT
                                                           July 04, 2014

     Re-ECN: Adding Accountability for Causing Congestion to TCP/IP
                   draft-briscoe-conex-re-ecn-tcp-04

Abstract

   This document introduces re-ECN (re-inserted explicit congestion
   notification), which is intended to make a simple but far-reaching
   change to the Internet architecture.  The sender uses the IP header
   to reveal the congestion that it expects on the end-to-end path.  The
   protocol works by arranging an extended ECN field in each packet so
   that, as it crosses any interface in an internetwork, it will carry a
   truthful prediction of congestion on the remainder of its path.  It
   can be deployed incrementally around unmodified routers.  The purpose
   of this document is to specify the re-ECN protocol at the IP layer
   and to give guidelines on any consequent changes required to
   transport protocols.  It includes the changes required to TCP both as
   an example and as a specification.  It briefly gives examples of
   mechanisms that can use the protocol to ensure data sources respond
   sufficiently to congestion, but these are described more fully in a
   companion document.

   Note concerning Intended Status: If this draft were ever published as
   an RFC it would probably have historic status.  There is limited
   space in the IP header, so re-ECN had to compromise by requiring the
   receiver to be ECN-enabled otherwise the sender could not use re-ECN.
   Re-ECN was a precursor to chartering of the IETF's Congestion
   Exposure (ConEx) working group, but during chartering there were
   still too few ECN receivers enabled, therefore it was decided to
   pursue other compromises in order to fit a similar capability into
   the IP header.

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

Briscoe, et al.          Expires January 5, 2015                [Page 1]
Internet-Draft   Re-ECN: Adding Accountability to TCP/IP       July 2014

   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 5, 2015.

Copyright Notice

   Copyright (c) 2014 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
   (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.  Requirements notation . . . . . . . . . . . . . . . . . . . .   5
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   5
   4.  Protocol Overview . . . . . . . . . . . . . . . . . . . . . .   6
     4.1.  Simplified Re-ECN Protocol  . . . . . . . . . . . . . . .   6
       4.1.1.  Congestion Control and Policing the Protocol  . . . .   6
       4.1.2.  Background and Applicability  . . . . . . . . . . . .   7
     4.2.  Re-ECN Abstracted Network Layer Wire Protocol (IPv4 or
           v6) . . . . . . . . . . . . . . . . . . . . . . . . . . .   8
     4.3.  Re-ECN Protocol Operation . . . . . . . . . . . . . . . .   9
     4.4.  Positive and Negative Flows . . . . . . . . . . . . . . .  11
   5.  Network Layer . . . . . . . . . . . . . . . . . . . . . . . .  12
     5.1.  Re-ECN IPv4 Wire Protocol . . . . . . . . . . . . . . . .  12
     5.2.  Re-ECN IPv6 Wire Protocol . . . . . . . . . . . . . . . .  14

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