SIPCORE G. Lavers Internet-Draft P. Jones Intended status: Standards Track G. Salgueiro Expires: September 6, 2012 Cisco Systems March 5, 2012 Indicating the Immersive User Agent Capability in the Session Initiation Protocol (SIP) draft-lavers-sipcore-immersive-capability-00 Abstract This document defines and registers with IANA the new 'immersive' media feature tag for use with the Session Initiation Protocol (SIP). This media feature tag can be used to route calls to a device that can provide an immersive communication experience, such as a Telepresence system. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on September 6, 2012. Copyright Notice Copyright (c) 2012 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 Lavers, et al. Expires September 6, 2012 [Page 1] Internet-Draft Immersive Media Feature Tag March 2012 the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4.1. Registration . . . . . . . . . . . . . . . . . . . . . . . 4 4.2. Session Establishment . . . . . . . . . . . . . . . . . . . 5 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 7 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 8.1. Normative References . . . . . . . . . . . . . . . . . . . 9 8.2. Informative References . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9 Lavers, et al. Expires September 6, 2012 [Page 2] Internet-Draft Immersive Media Feature Tag March 2012 1. Introduction Videoconferencing systems that utilize SIP [1] can be broadly classified as "traditional" videoconferencing systems or "Telepresence" systems. Most SIP implementations today are classified as traditional videoconferencing systems, but there are a growing number of telepresence systems that would benefit in differentiating the two through a media feature tag. The traditional videoconferencing system, which might include any room-based system, desktop videophone, or application running on a computer, tablet, mobile phone, or similar device, typically uses lower-resolution video images and does not make an attempt to provide a real-life, immersive conferencing experience. Some traditional systems do employ high definition (HD) video, but still lack the quality of providing an in-person communication experience. Telepresence systems, on the other hand, are visual conferencing environments that duplicate, as closely as possible, an in-person experience. The objective of such systems is to make the participants in the conference feel as if they are physically together, providing an immersive, realistic experience. This document defines the "immersive" media feature tag for use in the SIP tree, as per Section 12.1 of RFC 3840 [RFC3840]. This feature tag can be utilized by SIP B2BUAs, SIP proxies, or other elements in the SIP network to help ensure the best communication experience for those wishing to establish a telepresence session or other communication session that might be classified as providing an immersive, realistic user experience. 2. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. "SHOULD", "SHOULD NOT", "RECOMMENDED", and "NOT RECOMMENDED" are appropriate when valid exceptions to a general requirement are known to exist or appear to exist, and it is infeasible or impractical to enumerate all of them. However, they should not be interpreted as permitting implementors to fail to implement the general requirement when such failure would result in interoperability failure. Lavers, et al. Expires September 6, 2012 [Page 3] Internet-Draft Immersive Media Feature Tag March 2012 3. Motivation The primary motivation for defining an immersive media feature tag is for the transmission of a feature capability that implies a specific "user experience" that is differentiated from classic video. This feature tag can be considered by the various network elements to realize several possible use cases. To name a few: o Admission control decisions: A system could use the media feature tags such as immersive, video, audio, etc. to allow network elements to reserve bandwidth or take measures to ensure the best possible experience. o Selective routing decisions: A proxy or B2BUA could leverage the immersive feature tag to help make routing decisions, including the selection of a specific end system that supports the feature capability or to route a call over specific network segments. 4. Examples The following examples omit the message body and various header fields for brevity. 4.1. Registration Bob registers with the immersive media feature tag. The message flow is shown in Figure 1: SIP Registrar Bob's Telepresence Endpoint ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | | | REGISTER F1 | |<------------------------------| | | | 200 OK F2 | |------------------------------>| | | Figure 1: Immersive Media Feature Tag SIP Registration Example F1 REGISTER Bob -> Registrar Lavers, et al. Expires September 6, 2012 [Page 4] Internet-Draft Immersive Media Feature Tag March 2012 REGISTER sip:example.com SIP/2.0 Via: SIP/2.0/TCP bob-TP@example.com;branch=z9hG4bK309475a2 From: ;tag=a6c85cf To: Call-ID: a84b4c76e66710 Max-Forwards: 70 CSeq: 116 REGISTER Contact: ;immersive Expires: 3600 The registrar responds with a 200 OK: F2 200 OK Registrar -> Bob SIP/2.0 200 OK From: ;tag=a6c85cf To: ;tag=1263390604 Contact: ;immersive Expires: 120 Call-ID: a84b4c76e66710 Via: SIP/2.0/TCP bob-TP@example.com;branch=z9hG4bK309475a2 CSeq: 116 REGISTER Expires: 3600 4.2. Session Establishment Lavers, et al. Expires September 6, 2012 [Page 5] Internet-Draft Immersive Media Feature Tag March 2012 Bob initiates a delayed offer call to Alice indicating that he supports the immersive media feature tag while Alice responds with her support of the immersive media feature tag. The message flow is shown in Figure 2: Bob Alice ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | | | INVITE F1 | |------------------------------>| | | | 180 Ringing F2 | |<------------------------------| | | | 200 OK F3 | |<------------------------------| | | | ACK F4 | |------------------------------>| | | | Media F5 | |<=============================>| | | Figure 2: Immersive Media Feature Tag SIP Session Establishment Example F1 INVITE Bob -> Alice INVITE sip:alice@example.com SIP/2.0 Via: SIP/2.0/TCP bob-TP@example.com;branch=z9hG4bKnashds8 From: "bob" ;tag=a6c85cf To: "alice" Date: Tue, 01 Nov 2011 18:28:52 GMT Call-ID: a84b4c76e66710 CSeq: 101 INVITE Contact: ;immersive Max-Forwards: 69 Content-Length: 0 F2 180 Ringing Alice -> Bob Lavers, et al. Expires September 6, 2012 [Page 6] Internet-Draft Immersive Media Feature Tag March 2012 SIP/2.0 180 Ringing Via: SIP/2.0/TCP alice@example.com;branch=z9hG4bKnashds8 From: "alice" ;tag=1928301774 To: "bob" ;tag=a6c85cf Date: Tue, 01 Nov 2011 18:28:52 GMT Call-ID: a84b4c76e66710 CSeq: 101 INVITE Contact: ;immersive Content-Length: 0 F3 200 OK Alice -> Bob SIP/2.0 200 OK Via: SIP/2.0/TCP alice@example.com;branch=z9hG4bKnashds8 From: "alice" ;tag=1928301774 To: "bob" ;tag=a6c85cf Date: Tue, 01 Nov 2011 18:28:52 GMT Call-ID: a84b4c76e66710 CSeq: 101 INVITE Contact: ;immersive Content-Type: application/sdp Content-Length: 1963 F4 ACK Bob -> Alice ACK sip:aliceexample.com;transport=tcp SIP/2.0 Via: SIP/2.0/TCP 10.0.0.2:5060;branch=z9hG4bKnashds9 From: "bob" ;tag=a6c85cf To: "alice" ;tag=1928301774 Date: Tue, 01 Nov 2011 18:28:52 GMT Call-ID: a84b4c76e66710 Max-Forwards: 70 CSeq: 101 ACK Contact: ;immersive Content-Type: application/sdp Content-Length: 1452 F5 Media transmission Bob <-> Alice Media streams are established between Bob and Alice. 5. Security Considerations The security considerations related to the use of media feature tags from Section 11.1 of RFC 3840 [RFC3840] apply. Lavers, et al. Expires September 6, 2012 [Page 7] Internet-Draft Immersive Media Feature Tag March 2012 6. IANA Considerations This specification adds a new media feature tag to the SIP Media Feature Tag Registration Tree per the procedures defined in RFC 2506 [RFC2506] and RFC 3840 [RFC3840]. Media feature tag name: sip.immersive ASN.1 Identifier: 1.3.6.1.8.4.{PH} Summary of the media feature indicated by this tag: This feature tag indicates that the device provides an immersive audio and/or video communication experience. Values appropriate for use with this feature tag: Boolean. The feature tag is intended primarily for use in the following applications, protocols, services, or negotiation mechanisms: This feature tag is most useful in a communications application for describing the capabilities of a device, such as a Telepresence system. Examples of typical use: Routing a call to a multimedia communication system that can provide an immersive communication experience. Related standards or documents: RFCXXXX Security Considerations: Security considerations for this media feature tag are discussed in Section 5 of this document. [[NOTE TO RFC EDITOR: Please change {PH} above to the correct identifier for this entry in the IANA registry for iso.org.dod.internet.features.sip-tree (1.3.6.1.8.4)]] [[NOTE TO RFC EDITOR: Please change XXXX to the number assigned to this specification, and remove this paragraph on publication.]] 7. Acknowledgements Thanks go to the Medianet Session Control group at Cisco for their insightful discussion, advice and feedback that led to the creation of this document. 8. References Lavers, et al. Expires September 6, 2012 [Page 8] Internet-Draft Immersive Media Feature Tag March 2012 8.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3840] Rosenberg, J., Schulzrinne, H., and P. Kyzivat, "Indicating User Agent Capabilities in the Session Initiation Protocol (SIP)", RFC 3840, August 2004. 8.2. Informative References [RFC2506] Holtman, K., Mutz, A., and T. Hardie, "Media Feature Tag Registration Procedure", BCP 31, RFC 2506, March 1999. [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, June 2002. Authors' Addresses Glen Lavers Cisco Systems Mail Stop LKO2/3/ 5400 Meadows Road LAKE OSWEGO, OR 97035 US Email: glavers@cisco.com Paul E. Jones Cisco Systems 7025 Kit Creek Road Research Triangle Park, NC 27709 US Email: paulej@packetizer.com Lavers, et al. Expires September 6, 2012 [Page 9] Internet-Draft Immersive Media Feature Tag March 2012 Gonzalo Salgueiro Cisco Systems 7200-12 Kit Creek Road Research Triangle Park, NC 27709 US Email: gsalguei@cisco.com Lavers, et al. Expires September 6, 2012 [Page 10]