Controlled Delay Active Queue Management
draft-ietf-aqm-codel-10

Document Type Active Internet-Draft (aqm WG)
Last updated 2017-11-13 (latest revision 2017-10-13)
Replaces draft-aqm-codel, draft-nichols-tsvwg-codel
Stream IETF
Intended RFC status Experimental
Formats plain text xml pdf html bibtex
Reviews
Stream WG state Submitted to IESG for Publication (wg milestone: Dec 2015 - Submit first algorit... )
Document shepherd Wesley Eddy
Shepherd write-up Show (last changed 2016-11-02)
IESG IESG state RFC Ed Queue
Consensus Boilerplate Yes
Telechat date
Responsible AD Mirja K├╝hlewind
Send notices to (None)
IANA IANA review state Version Changed - Review Needed
IANA action state No IC
RFC Editor RFC Editor state RFC-EDITOR
AQM                                                           K. Nichols
Internet-Draft                                             Pollere, Inc.
Intended status: Experimental                                V. Jacobson
Expires: April 16, 2018                                 A. McGregor, ed.
                                                         J. Iyengar, ed.
                                                                  Google
                                                        October 13, 2017

                Controlled Delay Active Queue Management
                        draft-ietf-aqm-codel-10

Abstract

   This document describes a general framework called CoDel (Controlled
   Delay) that controls bufferbloat-generated excess delay in modern
   networking environments.  CoDel consists of an estimator, a setpoint,
   and a control loop.  It requires no configuration in normal Internet
   deployments.

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 https://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 April 16, 2018.

Copyright Notice

   Copyright (c) 2017 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
   (https://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

Nichols, et al.          Expires April 16, 2018                 [Page 1]
Internet-Draft                    CoDel                     October 2017

   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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions and terms used in this document . . . . . . . . .   4
   3.  Understanding the Building Blocks of Queue Management . . . .   5
     3.1.  Estimator . . . . . . . . . . . . . . . . . . . . . . . .   6
     3.2.  Target Setpoint . . . . . . . . . . . . . . . . . . . . .   8
     3.3.  Control Loop  . . . . . . . . . . . . . . . . . . . . . .  10
   4.  Overview of the Codel AQM . . . . . . . . . . . . . . . . . .  12
     4.1.  Non-starvation  . . . . . . . . . . . . . . . . . . . . .  13
     4.2.  Setting INTERVAL  . . . . . . . . . . . . . . . . . . . .  13
     4.3.  Setting TARGET  . . . . . . . . . . . . . . . . . . . . .  14
     4.4.  Use with multiple queues  . . . . . . . . . . . . . . . .  15
     4.5.  Setting up CoDel  . . . . . . . . . . . . . . . . . . . .  15
   5.  Annotated Pseudo-code for CoDel AQM . . . . . . . . . . . . .  16
     5.1.  Data Types  . . . . . . . . . . . . . . . . . . . . . . .  16
     5.2.  Per-queue state (codel_queue_t instance variables)  . . .  17
     5.3.  Constants . . . . . . . . . . . . . . . . . . . . . . . .  17
     5.4.  Enqueue routine . . . . . . . . . . . . . . . . . . . . .  17
     5.5.  Dequeue routine . . . . . . . . . . . . . . . . . . . . .  17
     5.6.  Helper routines . . . . . . . . . . . . . . . . . . . . .  19
     5.7.  Implementation considerations . . . . . . . . . . . . . .  20
   6.  Further Experimentation . . . . . . . . . . . . . . . . . . .  21
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  21
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  21
   9.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  21
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  22
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  22
     10.2.  Informative References . . . . . . . . . . . . . . . . .  22
     10.3.  URIs . . . . . . . . . . . . . . . . . . . . . . . . . .  23
   Appendix A.  Applying CoDel in the datacenter . . . . . . . . . .  24
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  25

1.  Introduction

   The "persistently full buffer" problem has been discussed in the IETF
Show full document text