draft-ietf-mmusic-duplication-grouping-03.txt		draft-ietf-mmusic-duplication-grouping-04.txt
	MMUSIC A. Begen		MMUSIC A. Begen
	Internet-Draft Cisco		Internet-Draft Cisco
	Intended status: Standards Track Y. Cai		Intended status: Standards Track Y. Cai
	Expires: January 12, 2014 Microsoft		Expires: May 25, 2014 Microsoft
	H. Ou		H. Ou
	Cisco		Cisco
	July 11, 2013		November 21, 2013
	Duplication Grouping Semantics in the Session Description Protocol		Duplication Grouping Semantics in the Session Description Protocol
	draft-ietf-mmusic-duplication-grouping-03		draft-ietf-mmusic-duplication-grouping-04
	Abstract		Abstract
	Packet loss is undesirable for real-time multimedia sessions, but can		Packet loss is undesirable for real-time multimedia sessions, but can
	occur due to congestion, or other unplanned network outages. This is		occur due to congestion, or other unplanned network outages. This is
	especially true for IP multicast networks, where packet loss patterns		especially true for IP multicast networks, where packet loss patterns
	can vary greatly between receivers. One technique that can be used		can vary greatly between receivers. One technique that can be used
	to recover from packet loss without incurring unbounded delay for all		to recover from packet loss without incurring unbounded delay for all
	the receivers is to duplicate the packets and send them in separate		the receivers is to duplicate the packets and send them in separate
	redundant streams. This document defines the semantics for grouping		redundant streams. This document defines the semantics for grouping
	skipping to change at page 1, line 44		skipping to change at page 1, line 44
	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 January 12, 2014.		This Internet-Draft will expire on May 25, 2014.
	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 26		skipping to change at page 2, line 26
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	2. Requirements Notation . . . . . . . . . . . . . . . . . . . . 3		2. Requirements Notation . . . . . . . . . . . . . . . . . . . . 3
	3. Duplication Grouping . . . . . . . . . . . . . . . . . . . . 3		3. Duplication Grouping . . . . . . . . . . . . . . . . . . . . 3
	3.1. "DUP" Grouping Semantics . . . . . . . . . . . . . . . . 3		3.1. "DUP" Grouping Semantics . . . . . . . . . . . . . . . . 3
	3.2. Duplication Grouping for SSRC-Multiplexed RTP Streams . . 3		3.2. Duplication Grouping for SSRC-Multiplexed RTP Streams . . 3
	3.3. SDP Offer/Answer Model Considerations . . . . . . . . . . 4		3.3. SDP Offer/Answer Model Considerations . . . . . . . . . . 4
	4. SDP Examples . . . . . . . . . . . . . . . . . . . . . . . . 4		4. SDP Examples . . . . . . . . . . . . . . . . . . . . . . . . 4
	4.1. Separate Source Addresses . . . . . . . . . . . . . . . . 4		4.1. Separate Source Addresses . . . . . . . . . . . . . . . . 4
	4.2. Separate Destination Addresses . . . . . . . . . . . . . 5		4.2. Separate Destination Addresses . . . . . . . . . . . . . 5
	4.3. Temporal Redundancy . . . . . . . . . . . . . . . . . . . 5		4.3. Temporal Redundancy . . . . . . . . . . . . . . . . . . . 6
	5. Security Considerations . . . . . . . . . . . . . . . . . . . 6		5. Security Considerations . . . . . . . . . . . . . . . . . . . 6
	6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6		6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
	7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 7		7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 7
	8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7		8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
	8.1. Normative References . . . . . . . . . . . . . . . . . . 7		8.1. Normative References . . . . . . . . . . . . . . . . . . 7
	8.2. Informative References . . . . . . . . . . . . . . . . . 8		8.2. Informative References . . . . . . . . . . . . . . . . . 7
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
	1. Introduction		1. Introduction
	The Real-time Transport Protocol (RTP) [RFC3550] is widely used today		The Real-time Transport Protocol (RTP) [RFC3550] is widely used today
	for delivering IPTV traffic, and other real-time multimedia sessions.		for delivering IPTV traffic, and other real-time multimedia sessions.
	Many of these applications support very large numbers of receivers,		Many of these applications support very large numbers of receivers,
	and rely on intra-domain UDP/IP multicast for efficient distribution		and rely on intra-domain UDP/IP multicast for efficient distribution
	of traffic within the network.		of traffic within the network.
	skipping to change at page 4, line 29		skipping to change at page 4, line 29
	A node that is receiving an offer from a sender may or may not		A node that is receiving an offer from a sender may or may not
	understand line grouping. It is also possible that the node		understand line grouping. It is also possible that the node
	understands line grouping but it does not understand the "DUP"		understands line grouping but it does not understand the "DUP"
	semantics. From the viewpoint of the sender of the offer, these		semantics. From the viewpoint of the sender of the offer, these
	cases are indistinguishable.		cases are indistinguishable.
	When a node is offered a session with the "DUP" grouping semantics		When a node is offered a session with the "DUP" grouping semantics
	but it does not support line grouping or the duplication grouping		but it does not support line grouping or the duplication grouping
	semantics, as per [RFC5888], the node responds to the offer either		semantics, as per [RFC5888], the node responds to the offer either
	(1) with an answer that ignores the grouping attribute or (2) with a		(1) with an answer that omits the grouping attribute or (2) with a
	refusal to the request (e.g., 488 Not Acceptable Here or 606 Not		refusal to the request (e.g., 488 Not Acceptable Here or 606 Not
	Acceptable in SIP).		Acceptable in SIP).
	In the first case, the original sender of the offer must send a new		In the first case, the original sender of the offer must send a new
	offer without any duplication grouping. In the second case, if the		offer without any duplication grouping. In the second case, if the
	sender of the offer still wishes to establish the session, it should		sender of the offer still wishes to establish the session, it should
	retry the request with an offer without the duplication grouping.		retry the request with an offer without the duplication grouping.
	This behavior is specified in [RFC5888].		This behavior is specified in [RFC5888].
	4. SDP Examples		4. SDP Examples
	skipping to change at page 6, line 28		skipping to change at page 6, line 31
	a=source-filter:incl IN IP4 233.252.0.1 198.51.100.1		a=source-filter:incl IN IP4 233.252.0.1 198.51.100.1
	a=rtpmap:100 MP2T/90000		a=rtpmap:100 MP2T/90000
	a=ssrc:1000 cname:ch1a@example.com		a=ssrc:1000 cname:ch1a@example.com
	a=ssrc:1010 cname:ch1a@example.com		a=ssrc:1010 cname:ch1a@example.com
	a=ssrc-group:DUP 1000 1010		a=ssrc-group:DUP 1000 1010
	a=duplication-delay:50		a=duplication-delay:50
	a=mid:Ch1		a=mid:Ch1
	5. Security Considerations		5. Security Considerations
			In general, the security considerations of [RFC4566] apply to this
			document as well.
	There is a weak threat for the receiver that the duplication grouping		There is a weak threat for the receiver that the duplication grouping
	can be modified to indicate relationships that do not exist. Such		can be modified to indicate relationships that do not exist. Such
	attacks might result in failure of the duplication mechanisms, and/or		attacks might result in failure of the duplication mechanisms, and/or
	mishandling of the media streams by the receivers.		mishandling of the media streams by the receivers.
	In order to avoid attacks of this sort, the SDP description needs to		In order to avoid attacks of this sort, the SDP description needs to
	be integrity protected and provided with source authentication. This		be integrity protected and provided with source authentication. This
	can, for example, be achieved on an end-to-end basis using S/MIME		can, for example, be achieved on an end-to-end basis using S/MIME
	[RFC5652] [RFC5751] when the SDP is used in a signaling packet using		[RFC5652] [RFC5751] when the SDP is used in a signaling packet using
	MIME types (application/sdp). Alternatively, HTTPS [RFC2818] or the		MIME types (application/sdp). Alternatively, HTTPS [RFC2818] or the
	authentication method in the Session Announcement Protocol (SAP)		authentication method in the Session Announcement Protocol (SAP)
	[RFC2974] could be used as well.		[RFC2974] could be used as well. As for the confidentiality, if it
			is desired, it can be useful to use a secure, encrypted transport
			method to carry the SDP description.
	6. IANA Considerations		6. IANA Considerations
	This document registers the following semantics with IANA in		This document registers the following semantics with IANA in
	Semantics for the 'group' SDP Attribute under SDP Parameters:		Semantics for the 'group' SDP Attribute under SDP Parameters:
	Note to the RFC Editor: In the following registrations, please		Note to the RFC Editor: In the following registrations, please
	replace "XXXX" with the number of this document prior to publication		replace "XXXX" with the number of this document prior to publication
	as an RFC.		as an RFC.
	skipping to change at page 8, line 9		skipping to change at page 8, line 5
	Media Attributes in the Session Description Protocol		Media Attributes in the Session Description Protocol
	(SDP)", RFC 5576, June 2009.		(SDP)", RFC 5576, June 2009.
	[RFC5888] Camarillo, G. and H. Schulzrinne, "The Session Description		[RFC5888] Camarillo, G. and H. Schulzrinne, "The Session Description
	Protocol (SDP) Grouping Framework", RFC 5888, June 2010.		Protocol (SDP) Grouping Framework", RFC 5888, June 2010.
	8.2. Informative References		8.2. Informative References
	[I-D.ietf-avtext-rtp-duplication]		[I-D.ietf-avtext-rtp-duplication]
	Begen, A. and C. Perkins, "Duplicating RTP Streams",		Begen, A. and C. Perkins, "Duplicating RTP Streams",
	draft-ietf-avtext-rtp-duplication-02 (work in progress),		draft-ietf-avtext-rtp-duplication-04 (work in progress),
	March 2013.		October 2013.
	[I-D.ietf-mmusic-delayed-duplication]		[I-D.ietf-mmusic-delayed-duplication]
	Begen, A., Cai, Y., and H. Ou, "Delayed Duplication		Begen, A., Cai, Y., and H. Ou, "Delayed Duplication
	Attribute in the Session Description Protocol", draft-		Attribute in the Session Description Protocol", draft-
	ietf-mmusic-delayed-duplication-02 (work in progress), May		ietf-mmusic-delayed-duplication-02 (work in progress), May
	2013.		2013.
	[IC2011] Evans, J., Begen, A., Greengrass, J., and C. Filsfils,		[IC2011] Evans, J., Begen, A., Greengrass, J., and C. Filsfils,
	"Toward Lossless Video Transport (to appear in IEEE		"Toward Lossless Video Transport, IEEE Internet Computing,
	Internet Computing)", November 2011.		vol. 15/6, pp. 48-57", November 2011.
	[RFC2354] Perkins, C. and O. Hodson, "Options for Repair of		[RFC2354] Perkins, C. and O. Hodson, "Options for Repair of
	Streaming Media", RFC 2354, June 1998.		Streaming Media", RFC 2354, June 1998.
	[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.		[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.
	[RFC2974] Handley, M., Perkins, C., and E. Whelan, "Session		[RFC2974] Handley, M., Perkins, C., and E. Whelan, "Session
	Announcement Protocol", RFC 2974, October 2000.		Announcement Protocol", RFC 2974, October 2000.
	[RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,		[RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
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