Evaluating Congestion Control for Interactive Real-Time Media
RFC 8868

• Status
• IESG evaluation record
• IESG writeups
• Email expansions
• History

• Versions
• 00
• 01
• 02
• 03
• 04
• 05
• 06
• 07
• 08
• 09
• 10
• 11
• 12
• 13
• 14



Internet Engineering Task Force (IETF)                          V. Singh
Request for Comments: 8868                                  callstats.io
Category: Informational                                           J. Ott
ISSN: 2070-1721                           Technical University of Munich
                                                               S. Holmer
                                                                  Google
                                                            January 2021

     Evaluating Congestion Control for Interactive Real-Time Media

Abstract

   The Real-Time Transport Protocol (RTP) is used to transmit media in
   telephony and video conferencing applications.  This document
   describes the guidelines to evaluate new congestion control
   algorithms for interactive point-to-point real-time media.

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 Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Not all documents
   approved by the IESG are candidates for any level of Internet
   Standard; see Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   https://www.rfc-editor.org/info/rfc8868.

Copyright Notice

   Copyright (c) 2021 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
   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.  Terminology
   3.  Metrics
     3.1.  RTP Log Format
   4.  List of Network Parameters
     4.1.  One-Way Propagation Delay
     4.2.  End-to-End Loss
     4.3.  Drop-Tail Router Queue Length
     4.4.  Loss Generation Model
     4.5.  Jitter Models
       4.5.1.  Random Bounded PDV (RBPDV)
       4.5.2.  Approximately Random Subject to No-Reordering Bounded
               PDV (NR-BPDV)
       4.5.3.  Recommended Distribution
   5.  Traffic Models
     5.1.  TCP Traffic Model
     5.2.  RTP Video Model
     5.3.  Background UDP
   6.  Security Considerations
   7.  IANA Considerations
   8.  References
     8.1.  Normative References
     8.2.  Informative References
   Contributors
   Acknowledgments
   Authors' Addresses

1.  Introduction

   This memo describes the guidelines to help with evaluating new
   congestion control algorithms for interactive point-to-point real-
   time media.  The requirements for the congestion control algorithm
   are outlined in [RFC8836].  This document builds upon previous work
   at the IETF: Specifying New Congestion Control Algorithms [RFC5033]
   and Metrics for the Evaluation of Congestion Control Algorithms
   [RFC5166].

   The guidelines proposed in the document are intended to help prevent
   a congestion collapse, to promote fair capacity usage, and to
   optimize the media flow's throughput.  Furthermore, the proposed
   congestion control algorithms are expected to operate within the
   envelope of the circuit breakers defined in RFC 8083 [RFC8083].

   This document only provides the broad set of network parameters and
   traffic models for evaluating a new congestion control algorithm.
   The minimal requirement for congestion control proposals is to
   produce or present results for the test scenarios described in
   [RFC8867] (Basic Test Cases), which also defines the specifics for
   the test cases.  Additionally, proponents may produce evaluation
   results for the wireless test scenarios [RFC8869].

   This document does not cover application-specific implications of
   congestion control algorithms and how those could be evaluated.
   Therefore, no quality metrics are defined for performance evaluation;
   quality metrics and the algorithms to infer those vary between media
   types.  Metrics and algorithms to assess, e.g., the quality of
   experience, evolve continuously so that determining suitable choices
   is left for future work.  However, there is consensus that each
   congestion control algorithm should be able to show that it is useful
   for interactive video by performing analysis using real codecs and
   video sequences and state-of-the-art quality metrics.

   Beyond optimizing individual metrics, real-time applications may have