Internet DRAFT - draft-lavers-dispatch-immersive-capability

draft-lavers-dispatch-immersive-capability






DISPATCH                                                       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-dispatch-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
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   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
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   include Simplified BSD License text as described in Section 4.e of



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   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
































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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.







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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







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   REGISTER sip:example.com SIP/2.0
   Via: SIP/2.0/TCP bob-TP@example.com;branch=z9hG4bK309475a2
   From: <sip:bob-tp@example.com>;tag=a6c85cf
   To: <sip:bob-tp@pexample.com>
   Call-ID: a84b4c76e66710
   Max-Forwards: 70
   CSeq: 116 REGISTER
   Contact: <sip:bob-tp@example.com;transport=tcp>;immersive
   Expires: 3600

   The registrar responds with a 200 OK:

   F2 200 OK Registrar -> Bob

   SIP/2.0 200 OK
   From: <sip:bob-tp@example.com>;tag=a6c85cf
   To: <sip:bob-tp@example.com>;tag=1263390604
   Contact: <sip:bob-tp@example.com;transport=tcp>;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


























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   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" <sip:bob-tp@example.com>;tag=a6c85cf
   To: "alice" <sip:alice@example.com>
   Date: Tue, 01 Nov 2011 18:28:52 GMT
   Call-ID: a84b4c76e66710
   CSeq: 101 INVITE
   Contact: <sip:bob-tp@example.com;transport=tcp>;immersive
   Max-Forwards: 69
   Content-Length: 0

   F2 180 Ringing Alice -> Bob









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   SIP/2.0 180 Ringing
   Via: SIP/2.0/TCP alice@example.com;branch=z9hG4bKnashds8
   From: "alice" <sip:alice@example.com>;tag=1928301774
   To: "bob" <sip:bob-tp@example.com>;tag=a6c85cf
   Date: Tue, 01 Nov 2011 18:28:52 GMT
   Call-ID: a84b4c76e66710
   CSeq: 101 INVITE
   Contact: <sip:alice@example.com;transport=tcp>;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" <sip:alice@example.com>;tag=1928301774
   To: "bob" <sip:bob-tp@example.com>;tag=a6c85cf
   Date: Tue, 01 Nov 2011 18:28:52 GMT
   Call-ID: a84b4c76e66710
   CSeq: 101 INVITE
   Contact: <sip:alice@example.com;transport=tcp>;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" <sip:bob-tp@example.com>;tag=a6c85cf
   To: "alice" <sip:alice@example.com>;tag=1928301774
   Date: Tue, 01 Nov 2011 18:28:52 GMT
   Call-ID: a84b4c76e66710
   Max-Forwards: 70
   CSeq: 101 ACK
   Contact: <sip:bob-tp@example.com;transport=tcp>;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.





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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




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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












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   Gonzalo Salgueiro
   Cisco Systems
   7200-12 Kit Creek Road
   Research Triangle Park, NC  27709
   US

   Email: gsalguei@cisco.com












































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