Shared Bottleneck Detection for Coupled Congestion Control for RTP Media.
draft-ietf-rmcat-sbd-09

Document Type Active Internet-Draft (rmcat WG)
Last updated 2017-12-06 (latest revision 2017-11-27)
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RTP Media Congestion Avoidance Techniques                  D. Hayes, Ed.
Internet-Draft                                Simula Research Laboratory
Intended status: Experimental                                  S. Ferlin
Expires: May 30, 2018
                                                                M. Welzl
                                                               K. Hiorth
                                                      University of Oslo
                                                       November 26, 2017

   Shared Bottleneck Detection for Coupled Congestion Control for RTP
                                 Media.
                        draft-ietf-rmcat-sbd-09

Abstract

   This document describes a mechanism to detect whether end-to-end data
   flows share a common bottleneck.  It relies on summary statistics
   that are calculated based on continuous measurements and used as
   input to a grouping algorithm that runs wherever the knowledge is
   needed.  This mechanism complements the coupled congestion control
   mechanism in draft-ietf-rmcat-coupled-cc.

Status of This Memo

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

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   This Internet-Draft will expire on May 30, 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

Hayes, et al.             Expires May 30, 2018                  [Page 1]
Internet-Draft         SBD for CCC with RTP Media          November 2017

   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  The Basic Mechanism . . . . . . . . . . . . . . . . . . .   3
     1.2.  The Signals . . . . . . . . . . . . . . . . . . . . . . .   3
       1.2.1.  Packet Loss . . . . . . . . . . . . . . . . . . . . .   3
       1.2.2.  Packet Delay  . . . . . . . . . . . . . . . . . . . .   4
       1.2.3.  Path Lag  . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Definitions . . . . . . . . . . . . . . . . . . . . . . . . .   4
     2.1.  Parameters and Their Effect . . . . . . . . . . . . . . .   6
     2.2.  Recommended Parameter Values  . . . . . . . . . . . . . .   7
   3.  Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . .   7
     3.1.  SBD Feedback Requirements . . . . . . . . . . . . . . . .   8
       3.1.1.  Feedback When All the Logic is Placed at the Sender .   9
       3.1.2.  Feedback When the Statistics are Calculated at the
               Receiver and SBD Performed at the Sender  . . . . . .   9
       3.1.3.  Feedback When Bottlenecks can be Determined at Both
               Senders and Receivers . . . . . . . . . . . . . . . .  10
     3.2.  Key Metrics and Their Calculation . . . . . . . . . . . .  10
       3.2.1.  Mean Delay  . . . . . . . . . . . . . . . . . . . . .  10
       3.2.2.  Skewness Estimate . . . . . . . . . . . . . . . . . .  11
       3.2.3.  Variability Estimate  . . . . . . . . . . . . . . . .  12
       3.2.4.  Oscillation Estimate  . . . . . . . . . . . . . . . .  12
       3.2.5.  Packet Loss . . . . . . . . . . . . . . . . . . . . .  13
     3.3.  Flow Grouping . . . . . . . . . . . . . . . . . . . . . .  13
       3.3.1.  Flow Grouping Algorithm . . . . . . . . . . . . . . .  13
       3.3.2.  Using the Flow Group Signal . . . . . . . . . . . . .  16
   4.  Enhancements to the Basic SBD Algorithm . . . . . . . . . . .  16
     4.1.  Reducing Lag and Improving Responsiveness . . . . . . . .  16
       4.1.1.  Improving the Response of the Skewness Estimate . . .  17
       4.1.2.  Improving the Response of the Variability Estimate  .  19
     4.2.  Removing Oscillation Noise  . . . . . . . . . . . . . . .  19
   5.  Measuring OWD . . . . . . . . . . . . . . . . . . . . . . . .  20
     5.1.  Time-stamp Resolution . . . . . . . . . . . . . . . . . .  20
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