RTP Control Protocol (RTCP) Port for Source-Specific Multicast (SSM) Sessions
RFC 6128
Document | Type |
RFC - Proposed Standard
(February 2011; No errata)
Updates RFC 5760
|
|
---|---|---|---|
Author | Ali Begen | ||
Last updated | 2015-10-14 | ||
Replaces | draft-begen-avt-rtcp-port-for-ssm | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Reviews | |||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 6128 (Proposed Standard) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Robert Sparks | ||
Send notices to | (None) |
Internet Engineering Task Force (IETF) A. Begen Request for Comments: 6128 Cisco Updates: 5760 February 2011 Category: Standards Track ISSN: 2070-1721 RTP Control Protocol (RTCP) Port for Source-Specific Multicast (SSM) Sessions Abstract The Session Description Protocol (SDP) has an attribute that allows RTP applications to specify an address and a port associated with the RTP Control Protocol (RTCP) traffic. In RTP-based source-specific multicast (SSM) sessions, the same attribute is used to designate the address and the RTCP port of the Feedback Target in the SDP description. However, the RTCP port associated with the SSM session itself cannot be specified by the same attribute to avoid ambiguity, and thus, is required to be derived from the "m=" line of the media description. Deriving the RTCP port from the "m=" line imposes an unnecessary restriction. This document removes this restriction by introducing a new SDP attribute. 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/rfc6128. Begen Standards Track [Page 1] RFC 6128 RTCP Port for Multicast Sessions February 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. The 'multicast-rtcp' Attribute ..................................3 3. SDP Example .....................................................3 4. Security Considerations .........................................4 5. IANA Considerations .............................................4 5.1. Registration of SDP Attributes .............................5 6. Acknowledgments .................................................5 7. References ......................................................5 7.1. Normative References .......................................5 7.2. Informative References .....................................5 1. Introduction The Session Description Protocol (SDP) [RFC4566] has an attribute that allows RTP applications [RFC3550] to specify an address and a port associated with the RTP Control Protocol (RTCP) traffic [RFC3605]. This attribute is called 'rtcp'. Now consider a network where one or more media senders send RTP packets to a distribution source, which then multicasts these RTP packets to multicast receivers using a source-specific multicast (SSM) arrangement [RFC5760]. The distribution source also multicasts the forward RTCP traffic (i.e., RTCP sender reports and receiver reports or their summaries) to the receivers in the same SSM session. In RTP-based SSM sessions, the 'rtcp' attribute is used to designate the address and the RTCP port of the Feedback Target in the SDP description [RFC5760]. However, the RTCP port associated with the SSM session itself cannot be specified by the same attribute since it could potentially cause ambiguity. Thus, the multicast RTCP port is required to be derived from the "m=" line of the media description Begen Standards Track [Page 2] RFC 6128 RTCP Port for Multicast Sessions February 2011 (see Section 10.2 of [RFC5760]) by following the +1 rule (see Section 11 of [RFC3550]). However, [RFC3550] lifted the requirement for the +1 rule since it imposed an unnecessary restriction on RTCP port selection. In this specification, we introduce a new SDP attribute to remove this restriction. The new attribute allows the multicast sender to use its desired port in the RTCP session. This document updatesShow full document text