draft-ietf-avtcore-6222bis-02.txt   draft-ietf-avtcore-6222bis-03.txt 
Network Working Group A. Begen Network Working Group A. Begen
Internet-Draft Cisco Internet-Draft Cisco
Obsoletes: 6222 (if approved) C. Perkins Obsoletes: 6222 (if approved) C. Perkins
Intended status: Standards Track University of Glasgow Intended status: Standards Track University of Glasgow
Expires: October 15, 2013 D. Wing Expires: October 25, 2013 D. Wing
Cisco Cisco
E. Rescorla E. Rescorla
RTFM, Inc. RTFM, Inc.
April 13, 2013 April 23, 2013
Guidelines for Choosing RTP Control Protocol (RTCP) Guidelines for Choosing RTP Control Protocol (RTCP)
Canonical Names (CNAMEs) Canonical Names (CNAMEs)
draft-ietf-avtcore-6222bis-02 draft-ietf-avtcore-6222bis-03
Abstract Abstract
The RTP Control Protocol (RTCP) Canonical Name (CNAME) is a The RTP Control Protocol (RTCP) Canonical Name (CNAME) is a
persistent transport-level identifier for an RTP endpoint. While the persistent transport-level identifier for an RTP endpoint. While the
Synchronization Source (SSRC) identifier of an RTP endpoint may Synchronization Source (SSRC) identifier of an RTP endpoint may
change if a collision is detected or when the RTP application is change if a collision is detected or when the RTP application is
restarted, its RTCP CNAME is meant to stay unchanged, so that RTP restarted, its RTCP CNAME is meant to stay unchanged, so that RTP
endpoints can be uniquely identified and associated with their RTP endpoints can be uniquely identified and associated with their RTP
media streams. media streams.
skipping to change at page 2, line 4 skipping to change at page 2, line 4
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on October 15, 2013. This Internet-Draft will expire on October 25, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 39 skipping to change at page 2, line 39
4.2. Requirements . . . . . . . . . . . . . . . . . . . . . . 5 4.2. Requirements . . . . . . . . . . . . . . . . . . . . . . 5
5. Procedure to Generate a Unique Identifier . . . . . . . . . . 6 5. Procedure to Generate a Unique Identifier . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . 7 6. Security Considerations . . . . . . . . . . . . . . . . . . . 7
6.1. Considerations on Uniqueness of RTCP CNAMEs . . . . . . . 7 6.1. Considerations on Uniqueness of RTCP CNAMEs . . . . . . . 7
6.2. Session Correlation Based on RTCP CNAMEs . . . . . . . . 7 6.2. Session Correlation Based on RTCP CNAMEs . . . . . . . . 7
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 8 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 8
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
9.1. Normative References . . . . . . . . . . . . . . . . . . 8 9.1. Normative References . . . . . . . . . . . . . . . . . . 8
9.2. Informative References . . . . . . . . . . . . . . . . . 8 9.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction 1. Introduction
In Section 6.5.1 of the RTP specification, [RFC3550], there are a 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 number of recommendations for choosing a unique RTCP CNAME for an RTP
endpoint. However, in practice, some of these methods are not endpoint. However, in practice, some of these methods are not
guaranteed to produce a unique RTCP CNAME. [RFC6222] updated the guaranteed to produce a unique RTCP CNAME. [RFC6222] updated the
guidelines for choosing RTCP CNAMEs, superseding those presented in guidelines for choosing RTCP CNAMEs, superseding those presented in
Section 6.5.1 of [RFC3550]. Unfortunately, some parts of the new Section 6.5.1 of [RFC3550]. Unfortunately, some parts of the new
algorithms are rather complicated and also produce RTCP CNAMEs which algorithms are rather complicated and also produce RTCP CNAMEs which
skipping to change at page 5, line 49 skipping to change at page 5, line 49
procedure is performed once per initialization of the software. procedure is performed once per initialization of the software.
After obtaining an identifier in case of (a), the 48 bits are After obtaining an identifier in case of (a), the 48 bits are
converted to the standard colon-separated hexadecimal format converted to the standard colon-separated hexadecimal format
[RFC5342], e.g., "00:23:32:af:9b:aa", resulting in a 17-octet [RFC5342], e.g., "00:23:32:af:9b:aa", resulting in a 17-octet
printable string representation. In case of (b), minimally the printable string representation. In case of (b), minimally the
least significant 96 bits SHOULD be converted to ASCII using least significant 96 bits SHOULD be converted to ASCII using
Base64 encoding [RFC4648] (to compromise between packet size and Base64 encoding [RFC4648] (to compromise between packet size and
uniqueness - refer to Section 6.1). If 96 bits are used, the uniqueness - refer to Section 6.1). If 96 bits are used, the
resulting string will be 16 octets. resulting string will be 16 octets.
In some environments (for example, a virtualized operating
system), the MAC address may not be unique as expected. In these
cases, using option (b) above is RECOMMENDED.
In the two cases above, the "user@" part of the RTCP CNAME MAY be In the two cases above, the "user@" part of the RTCP CNAME MAY be
omitted on single-user systems and MAY be replaced by an opaque token omitted on single-user systems and MAY be replaced by an opaque token
on multi-user systems, to preserve privacy. on multi-user systems, to preserve privacy.
An RTP endpoint that wishes to generate a per-session RTCP CNAME MUST An RTP endpoint that wishes to generate a per-session RTCP CNAME MUST
use the following method: use the following method:
o For every new RTP session, a new CNAME is generated following the o For every new RTP session, a new CNAME is generated following the
procedure described in Section 5. After performing that procedure described in Section 5. After performing that
procedure, minimally the least significant 96 bits SHOULD be procedure, minimally the least significant 96 bits SHOULD be
 End of changes. 6 change blocks. 
5 lines changed or deleted 9 lines changed or added

This html diff was produced by rfcdiff 1.33. The latest version is available from http://tools.ietf.org/tools/rfcdiff/