Guidelines for Choosing RTP Control Protocol (RTCP) Canonical Names (CNAMEs)
RFC 7022

Document Type RFC - Proposed Standard (September 2013; No errata)
Obsoletes RFC 6222
Updates RFC 3550
Last updated 2013-09-03
Replaces draft-rescorla-avtcore-6222bis
Stream IETF
Formats plain text pdf html
Stream WG state Submitted to IESG for Publication
Consensus Unknown
Document shepherd Magnus Westerlund
Shepherd write-up Show (last changed 2013-06-21)
IESG IESG state RFC 7022 (Proposed Standard)
Telechat date
Responsible AD Richard Barnes
Send notices to avtcore-chairs@ietf.org, draft-ietf-avtcore-6222bis@ietf.org
IANA IANA review state Version Changed - Review Needed
IANA action state No IC
Internet Engineering Task Force (IETF)                          A. Begen
Request for Comments: 7022                                         Cisco
Obsoletes: 6222                                               C. Perkins
Updates: 3550                                      University of Glasgow
Category: Standards Track                                        D. Wing
ISSN: 2070-1721                                                    Cisco
                                                             E. Rescorla
                                                              RTFM, Inc.
                                                          September 2013

          Guidelines for Choosing RTP Control Protocol (RTCP)
                        Canonical Names (CNAMEs)

Abstract

   The RTP Control Protocol (RTCP) Canonical Name (CNAME) is a
   persistent transport-level identifier for an RTP endpoint.  While the
   Synchronization Source (SSRC) identifier of an RTP endpoint may
   change if a collision is detected or when the RTP application is
   restarted, its RTCP CNAME is meant to stay unchanged, so that RTP
   endpoints can be uniquely identified and associated with their RTP
   media streams.

   For proper functionality, RTCP CNAMEs should be unique within the
   participants of an RTP session.  However, the existing guidelines for
   choosing the RTCP CNAME provided in the RTP standard (RFC 3550) are
   insufficient to achieve this uniqueness.  RFC 6222 was published to
   update those guidelines to allow endpoints to choose unique RTCP
   CNAMEs.  Unfortunately, later investigations showed that some parts
   of the new algorithms were unnecessarily complicated and/or
   ineffective.  This document addresses these concerns and replaces RFC
   6222.

Status of This Memo

   This is an Internet Standards Track document.

   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).  Further information on
   Internet Standards is available in 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/rfc7022.

Begen, et al.                Standards Track                    [Page 1]
RFC 7022                 Choosing an RTCP CNAME           September 2013

Copyright Notice

   Copyright (c) 2013 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.  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
   2. Requirements Notation ...........................................3
   3. Deficiencies with Earlier Guidelines for Choosing an
      RTCP CNAME ......................................................3
   4. Choosing an RTCP CNAME ..........................................4
      4.1. Persistent RTCP CNAMEs versus Per-Session RTCP CNAMEs ......4
      4.2. Requirements ...............................................5
   5. Procedure to Generate a Unique Identifier .......................6
   6. Security Considerations .........................................7
      6.1. Considerations on Uniqueness of RTCP CNAMEs ................7
      6.2. Session Correlation Based on RTCP CNAMEs ...................7
   7. Acknowledgments .................................................8
   8. References ......................................................8
      8.1. Normative References .......................................8
      8.2. Informative References .....................................8

1.  Introduction

   In Section 6.5.1 of [RFC3550], there are a number of recommendations
   for choosing a unique RTCP CNAME for an RTP endpoint.  However, in
   practice, some of these methods are not guaranteed to produce a
   unique RTCP CNAME.  [RFC6222] updated the guidelines for choosing
   RTCP CNAMEs, superseding those presented in Section 6.5.1 of
   [RFC3550].  Unfortunately, some parts of the new algorithms are
   rather complicated and also produce RTCP CNAMEs that, in some cases,
   are potentially linkable over multiple RTCP sessions even if a new
Show full document text