datatracker.ietf.org
Sign in
Version 5.9.0, 2014-12-18
Report a bug

TCP modifications for Congestion Exposure
draft-ietf-conex-tcp-modifications-06

Document type: Active Internet-Draft (conex WG)
Document stream: IETF
Last updated: 2014-11-13
Intended RFC status: Unknown
Other versions: plain text, xml, pdf, html

IETF State: WG Document
Document shepherd: No shepherd assigned

IESG State: I-D Exists
Responsible AD: (None)
Send notices to: No addresses provided

Congestion Exposure (ConEx)                           M. Kuehlewind, Ed.
Internet-Draft                                                ETH Zurich
Intended status: Experimental                           R. Scheffenegger
Expires: May 17, 2015                                       NetApp, Inc.
                                                       November 13, 2014

               TCP modifications for Congestion Exposure
                 draft-ietf-conex-tcp-modifications-06

Abstract

   Congestion Exposure (ConEx) is a mechanism by which senders inform
   the network about the congestion encountered by previous packets on
   the same flow.  This document describes the necessary modifications
   to use ConEx with the Transmission Control Protocol (TCP).

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 May 17, 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.

Kuehlewind & ScheffeneggerExpires May 17, 2015                  [Page 1]
Internet-Draft  TCP modifications for Congestion Exposure  November 2014

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Sender-side Modifications . . . . . . . . . . . . . . . . . .   3
   3.  Accounting congestion . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Loss Detection  . . . . . . . . . . . . . . . . . . . . .   5
       3.1.1.  Without SACK Support  . . . . . . . . . . . . . . . .   6
     3.2.  ECN . . . . . . . . . . . . . . . . . . . . . . . . . . .   6
       3.2.1.  Accurate ECN feedback . . . . . . . . . . . . . . . .   8
       3.2.2.  Classic ECN support . . . . . . . . . . . . . . . . .   8
   4.  Setting the ConEx Bits  . . . . . . . . . . . . . . . . . . .   9
     4.1.  Setting the E and the L Bit . . . . . . . . . . . . . . .   9
     4.2.  Credit Bits . . . . . . . . . . . . . . . . . . . . . . .   9
   5.  Loss of ConEx information . . . . . . . . . . . . . . . . . .  11
   6.  Timeliness of the ConEx Signals . . . . . . . . . . . . . . .  11
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  11
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  12
     10.2.  Informative References . . . . . . . . . . . . . . . . .  12
   Appendix A.  Revision history . . . . . . . . . . . . . . . . . .  13
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  14

1.  Introduction

   Congestion Exposure (ConEx) is a mechanism by which senders inform
   the network about the congestion encountered by previous packets on
   the same flow.  ConEx concepts and use cases are further explained in
   [RFC6789].  The abstract ConEx mechanism is explained in
   [draft-ietf-conex-abstract-mech].  This document describes the
   necessary modifications to use ConEx with the Transmission Control
   Protocol (TCP).

   The needed markings to provide ConEx signaling are defined in the
   ConEx Destination Option (CDO) for IPv6 [draft-ietf-conex-destopt].
   Specifically, the use of four bits are defined: the X (ConEx-
   capable), the L (loss experienced), the E (ECN experienced) and C
   (credit) bit.

   ConEx signaling is based on loss or Explicit Congestion Notification
   (ECN) marks [RFC3168] as a congestion indication.  This congestion

[include full document text]