Byte and Packet Congestion Notification
draft-ietf-tsvwg-byte-pkt-congest-10

The information below is for an old version of the document
Document Type Active Internet-Draft (tsvwg WG)
Last updated 2013-07-11 (latest revision 2013-05-23)
Replaces draft-briscoe-tsvwg-byte-pkt-mark
Stream IETF
Intended RFC status Best Current Practice
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Stream WG state WG Document
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IESG IESG state AD is watching
Telechat date
Responsible AD Martin Stiemerling
IESG note Gorry Fairhurst (gorry@erg.abdn.ac.uk) is the document shepherd.
Send notices to tsvwg-chairs@tools.ietf.org, draft-ietf-tsvwg-byte-pkt-congest@tools.ietf.org
IANA IANA review state IANA - Review Needed
IANA action state None
Transport Area Working Group                                  B. Briscoe
Internet-Draft                                                        BT
Updates: 2309 (if approved)                                    J. Manner
Intended status: BCP                                    Aalto University
Expires: November 24, 2013                                  May 23, 2013

                Byte and Packet Congestion Notification
                  draft-ietf-tsvwg-byte-pkt-congest-10

Abstract

   This document provides recommendations of best current practice for
   dropping or marking packets using any active queue management (AQM)
   algorithm, such as random early detection (RED), BLUE, pre-congestion
   notification (PCN), etc.  We give three strong recommendations: (1)
   packet size should be taken into account when transports read and
   respond to congestion indications, (2) packet size should not be
   taken into account when network equipment creates congestion signals
   (marking, dropping), and therefore (3) in the specific case of RED,
   the byte-mode packet drop variant that drops fewer small packets
   should not be used.  This memo updates RFC 2309 to deprecate
   deliberate preferential treatment of small packets in AQM algorithms.

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 November 24, 2013.

Copyright Notice

   Copyright (c) 2013 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

Briscoe & Manner        Expires November 24, 2013               [Page 1]
Internet-Draft   Byte and Packet Congestion Notification        May 2013

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

Briscoe & Manner        Expires November 24, 2013               [Page 2]
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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
     1.1.  Terminology and Scoping  . . . . . . . . . . . . . . . . .  6
     1.2.  Example Comparing Packet-Mode Drop and Byte-Mode Drop  . .  7
   2.  Recommendations  . . . . . . . . . . . . . . . . . . . . . . .  9
     2.1.  Recommendation on Queue Measurement  . . . . . . . . . . .  9
     2.2.  Recommendation on Encoding Congestion Notification . . . . 10
     2.3.  Recommendation on Responding to Congestion . . . . . . . . 11
     2.4.  Recommendation on Handling Congestion Indications when
           Splitting or Merging Packets . . . . . . . . . . . . . . . 12
   3.  Motivating Arguments . . . . . . . . . . . . . . . . . . . . . 12
     3.1.  Avoiding Perverse Incentives to (Ab)use Smaller Packets  . 12
     3.2.  Small != Control . . . . . . . . . . . . . . . . . . . . . 14
     3.3.  Transport-Independent Network  . . . . . . . . . . . . . . 14
     3.4.  Partial Deployment of AQM  . . . . . . . . . . . . . . . . 15
     3.5.  Implementation Efficiency  . . . . . . . . . . . . . . . . 17
   4.  A Survey and Critique of Past Advice . . . . . . . . . . . . . 17
     4.1.  Congestion Measurement Advice  . . . . . . . . . . . . . . 17
       4.1.1.  Fixed Size Packet Buffers  . . . . . . . . . . . . . . 18
       4.1.2.  Congestion Measurement without a Queue . . . . . . . . 19
     4.2.  Congestion Notification Advice . . . . . . . . . . . . . . 20
       4.2.1.  Network Bias when Encoding . . . . . . . . . . . . . . 20
       4.2.2.  Transport Bias when Decoding . . . . . . . . . . . . . 21
       4.2.3.  Making Transports Robust against Control Packet
               Losses . . . . . . . . . . . . . . . . . . . . . . . . 23
       4.2.4.  Congestion Notification: Summary of Conflicting
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