Guidelines for Choosing RTP Control Protocol (RTCP) Canonical Names (CNAMEs)
RFC 6222

Document Type RFC - Proposed Standard (April 2011; No errata)
Obsoleted by RFC 7022
Updates RFC 3550
Last updated 2013-03-02
Replaces draft-begen-avt-rtp-cnames
Stream IETF
Formats plain text pdf html
Stream WG state (None)
Consensus Unknown
Document shepherd No shepherd assigned
IESG IESG state RFC 6222 (Proposed Standard)
Telechat date
Responsible AD Robert Sparks
Send notices to avt-chairs@ietf.org, draft-ietf-avt-rtp-cnames@ietf.org
Internet Engineering Task Force (IETF)                          A. Begen
Request for Comments: 6222                                         Cisco
Updates: 3550                                                 C. Perkins
Category: Standards Track                          University of Glasgow
ISSN: 2070-1721                                                  D. Wing
                                                                   Cisco
                                                              April 2011

          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 are insufficient to achieve this uniqueness.  This memo
   updates those guidelines to allow endpoints to choose unique RTCP
   CNAMEs.

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/rfc6222.

Begen, et al.                Standards Track                    [Page 1]
RFC 6222                 Choosing an RTCP CNAME               April 2011

Copyright Notice

   Copyright (c) 2011 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 ...........................................2
   3. Deficiencies with Earlier Guidelines for Choosing an
      RTCP CNAME ......................................................3
   4. Choosing an RTCP CNAME ..........................................3
      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 .....................................9

1.  Introduction

   In Section 6.5.1 of the RTP specification, [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.  This memo updates
   guidelines for choosing RTCP CNAMEs, superseding those presented in
   Section 6.5.1 of [RFC3550].

2.  Requirements Notation

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   [RFC2119].

Begen, et al.                Standards Track                    [Page 2]
RFC 6222                 Choosing an RTCP CNAME               April 2011
Show full document text