Report from the IAB/IRTF Workshop on Congestion Control for Interactive Real-Time Communication
RFC 7295

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Internet Architecture Board (IAB)                          H. Tschofenig
Request for Comments: 7295                                     L. Eggert
Category: Informational                                        Z. Sarker
ISSN: 2070-1721                                                July 2014

        Report from the IAB/IRTF Workshop on Congestion Control
                for Interactive Real-Time Communication

Abstract

   This document provides a summary of the IAB/IRTF Workshop on
   'Congestion Control for Interactive Real-Time Communication', which
   took place in Vancouver, Canada, on July 28, 2012.  The main goal of
   the workshop was to foster a discussion on congestion control
   mechanisms for interactive real-time communication.  This report
   summarizes the discussions and lists recommendations to the Internet
   Engineering Task Force (IETF) community.

   The views and positions in this report are those of the workshop
   participants and do not necessarily reflect the views and positions
   of the authors, the Internet Architecture Board (IAB), or the
   Internet Research Task Force (IRTF).

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This document is a product of the Internet Architecture Board (IAB)
   and represents information that the IAB has deemed valuable to
   provide for permanent record.  It represents the consensus of the
   Internet Architecture Board (IAB).  Documents approved for
   publication by the IAB are not a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7295.

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RFC 7295           Congestion Control Workshop Report          July 2014

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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Workshop Structure  . . . . . . . . . . . . . . . . . . . . .   5
     2.1.  History and Current Challenges  . . . . . . . . . . . . .   5
     2.2.  Simulations and Measurements  . . . . . . . . . . . . . .   8
     2.3.  Design Aspects of Problems and Solutions  . . . . . . . .   9
   3.  Recommendations . . . . . . . . . . . . . . . . . . . . . . .  13
     3.1.  Changes to Network Infrastructure . . . . . . . . . . . .  14
     3.2.  Avoiding Self-Inflicted Queuing . . . . . . . . . . . . .  15
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .  17
   5.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  17
   6.  Informative References  . . . . . . . . . . . . . . . . . . .  17
   Appendix A.  Program Committee  . . . . . . . . . . . . . . . . .  22
   Appendix B.  Workshop Material  . . . . . . . . . . . . . . . . .  22
   Appendix C.  Accepted Position Papers . . . . . . . . . . . . . .  22
   Appendix D.  Workshop Participants  . . . . . . . . . . . . . . .  24

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RFC 7295           Congestion Control Workshop Report          July 2014

1.  Introduction

   The Internet Architecture Board (IAB) holds occasional workshops
   designed to consider long-term issues and strategies for the
   Internet, and to suggest future directions for the Internet
   architecture.  This long-term planning function of the IAB is
   complementary to the ongoing engineering efforts performed by working
   groups of the Internet Engineering Task Force (IETF), under the
   leadership of the Internet Engineering Steering Group (IESG) and area
   directorates.

   Any application that sends significant amounts of data over the
   Internet is expected to implement reasonable congestion control
   behavior.  The goals for congestion control are well understood and
   documented in RFC 2914 [2] and RFC 5405 [1]:

   1.  Preventing congestion collapse.

   2.  Allowing multiple flows to share the network fairly.

   The Internet has been used for interactive real-time communication
   for decades, most of which is being transmitted using the Real-Time
   Transport Protocol (RTP) over UDP, often over provisioned capacity
   and/or using only rudimentary congestion control mechanisms.  In
   2004, the IAB raised concerns regarding possibilities of a congestion
   collapse due to a rapid growth in real-time voice traffic that does