DualQ Coupled AQMs for Low Latency, Low Loss and Scalable Throughput (L4S)
draft-ietf-tsvwg-aqm-dualq-coupled-08

Document Type Active Internet-Draft (tsvwg WG)
Last updated 2018-11-04
Replaces draft-briscoe-tsvwg-aqm-dualq-coupled
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Document shepherd Wesley Eddy
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Transport Area working group (tsvwg)                      K. De Schepper
Internet-Draft                                           Nokia Bell Labs
Intended status: Experimental                            B. Briscoe, Ed.
Expires: May 8, 2019                                           CableLabs
                                                           O. Bondarenko
                                                     Simula Research Lab
                                                                I. Tsang
                                                                   Nokia
                                                       November 04, 2018

  DualQ Coupled AQMs for Low Latency, Low Loss and Scalable Throughput
                                 (L4S)
                 draft-ietf-tsvwg-aqm-dualq-coupled-08

Abstract

   The Low Latency Low Loss Scalable Throughput (L4S) architecture
   allows data flows over the public Internet to predictably achieve
   ultra-low queuing latency, generally zero congestion loss and scaling
   of per-flow throughput without the problems of traditional TCP.  To
   achieve this, L4S data flows use a 'scalable' congestion control
   similar to Data Centre TCP (DCTCP) and a form of Explicit Congestion
   Notification (ECN) with modified behaviour.  However, until now,
   scalable congestion controls did not co-exist with existing TCP Reno/
   Cubic traffic---scalable controls are so aggressive that 'Classic'
   TCP algorithms drive themselves to starvation.  Therefore, until now,
   L4S controls could only be deployed where a clean-slate environment
   could be arranged, such as in private data centres (hence the name
   DCTCP).  This specification defines `DualQ Coupled Active Queue
   Management (AQM)', which enables these scalable congestion controls
   to safely co-exist with Classic Internet traffic.

   The Coupled AQM ensures that a flow runs at about the same rate
   whether it uses DCTCP or TCP Reno/Cubic.  It achieves this
   indirectly, without having to inspect transport layer flow
   identifiers, When tested in a residential broadband setting, DCTCP
   also achieves sub-millisecond average queuing delay and zero
   congestion loss under a wide range of mixes of DCTCP and `Classic'
   broadband Internet traffic, without compromising the performance of
   the Classic traffic.  The solution also reduces network complexity
   and eliminates network configuration.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

De Schepper, et al.        Expires May 8, 2019                  [Page 1]
Internet-Draft             DualQ Coupled AQMs              November 2018

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Copyright Notice

   Copyright (c) 2018 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Problem and Scope . . . . . . . . . . . . . . . . . . . .   3
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   5
     1.3.  Features  . . . . . . . . . . . . . . . . . . . . . . . .   6
   2.  DualQ Coupled AQM . . . . . . . . . . . . . . . . . . . . . .   7
     2.1.  Coupled AQM . . . . . . . . . . . . . . . . . . . . . . .   8
     2.2.  Dual Queue  . . . . . . . . . . . . . . . . . . . . . . .   9
     2.3.  Traffic Classification  . . . . . . . . . . . . . . . . .   9
     2.4.  Overall DualQ Coupled AQM Structure . . . . . . . . . . .  10
     2.5.  Normative Requirements for a DualQ Coupled AQM  . . . . .  12
       2.5.1.  Functional Requirements . . . . . . . . . . . . . . .  12
         2.5.1.1.  Requirements in Unexpected Cases  . . . . . . . .  13
       2.5.2.  Management Requirements . . . . . . . . . . . . . . .  15
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  16
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