One document matched: draft-elwell-sipping-update-pai-00.txt

SIPPING WG                                                     J. Elwell
Internet-Draft                         Siemens Enterprise Communications
Updates: RFC 3325 (if approved)                                  Limited
Intended status: Informational                          October 13, 2006
Expires: April 16, 2007


 The use of Asserted Identity in the Session Initiation Protocol (SIP)
                             UPDATE method
                 draft-elwell-sipping-update-pai-00.txt

Status of this Memo

   By submitting this Internet-Draft, each author represents that any
   applicable patent or other IPR claims of which he or she is aware
   have been or will be disclosed, and any of which he or she becomes
   aware will be disclosed, in accordance with Section 6 of BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   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."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt.

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on April 16, 2007.

Copyright Notice

   Copyright (C) The Internet Society (2006).

Abstract

   SIP has a mechanism for conveying the asserted identity of the
   originator of a request by means of the P-Asserted-Identity header
   field.  This header field is specified for use in requests using a
   number of SIP methods, in particular the INVITE method.  However, it
   is not specified for use in requests using the SIP UPDATE method.
   This document extends RFC 3325 by allowing use of the P-Asserted-



Elwell                   Expires April 16, 2007                 [Page 1]

Internet-Draft       Asserted Identity in SIP UPDATE        October 2006


   Identity header field in UPDATE requests.

   This work is being discussed on the sipping@ietf.org mailing list.


Table of Contents

   1.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  Use cases . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   4.  Behaviour . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
     4.1.  UAC Behaviour . . . . . . . . . . . . . . . . . . . . . . . 4
     4.2.  Proxy Behaviour . . . . . . . . . . . . . . . . . . . . . . 4
     4.3.  UAS Behaviour . . . . . . . . . . . . . . . . . . . . . . . 4
   5.  Security considerations . . . . . . . . . . . . . . . . . . . . 4
   6.  Normative References  . . . . . . . . . . . . . . . . . . . . . 4
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . . . 5
   Intellectual Property and Copyright Statements  . . . . . . . . . . 6

































Elwell                   Expires April 16, 2007                 [Page 2]

Internet-Draft       Asserted Identity in SIP UPDATE        October 2006


1.  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 RFC-2119 [2].


2.  Introduction

   SIP (RFC 3261 [1]) has a mechanism for conveying the asserted
   identity of the originator of a request by means of the P-Asserted-
   Identity header field (RFC 3325 [4]).  This header field is specified
   for use in requests using a number of SIP methods, in particular the
   INVITE method.  However, it is not specified for use in requests
   using the SIP UPDATE method (RFC 3311 [3]).  This document extends
   RFC 3325 by allowing use of the P-Asserted-Identity header field in
   UPDATE requests.


3.  Use cases

   There are several use cases that would benefit from the use of the
   P-Asserted-Identity header field in an UPDATE request.  These use
   cases apply within a trusted environment where the use of asserted
   identity is appropriate (see RFC 3325).

   In one example an established call passes through a gateway to the
   PSTN.  The gateway becomes aware that the remote party in the PSTN
   has changed, e.g., due to call transfer.  By including the
   P-Asserted-Identity header field in an UPDATE request, the gateway
   can convey the identity of the new remote party to the peer SIP UA.

      Note that the (re-)INVITE method could be used in this situation.
      However, this forces an offer-answer exchange, which typically is
      not required in this situation.  Also it involves 3 messages
      rather than 2.

   In another example, a B2BUA that provides third party call control
   (3PCC) wishes to join two calls together, one of which is still
   waiting to be answered and potentially is forked to different UAs.
   At this point in time it is not possible to trigger the normal offer-
   answer exchange between the two joined parties, because of the
   mismatch between a single dialog on the one side and potentially
   multiple early dialogs on the other side, so this action must wait
   until one of the called UAs answers.  However, it would be useful to
   give an early indication to each user concerned of the identity of
   the user to which they will become connected when the call is
   answered.  This can be achieved by the B2BUA sending an UPDATE



Elwell                   Expires April 16, 2007                 [Page 3]

Internet-Draft       Asserted Identity in SIP UPDATE        October 2006


   request with a P-Asserted-Identity header field on the dialogs
   concerned.


4.  Behaviour

   This updates RFC 3325 by allowing a P-Asserted-Identity header field
   to appear in an UPDATE request.

4.1.  UAC Behaviour

   A UAC MAY include a P-Asserted-Identity header field in an UPDATE
   request to report the identity of the user on behalf of which the UAC
   is acting and whose identity the UAC is in a position to assert.
   This can be an UPDATE request sent specially for this purpose or an
   UPDATE request sent for some other purpose.

4.2.  Proxy Behaviour

   If a UAC receives an UPDATE request containing a P-Asserted-Identity
   header field, it MUST behave as for any other request in accordance
   with the rules of RFC 3325 for a proxy.

4.3.  UAS Behaviour

   If a UAC receives an UPDATE request containing a P-Asserted-Identity
   header field, it MUST behave as for any other request in accordance
   with the rules of RFC 3325 for a UAS.


5.  Security considerations

   The use of asserted identity raises a number of security
   considerations, which are discussed fully in RFC 3325 [4].  This
   document does not introduce any additional security considerations.


6.  Normative References

   [1]  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.

   [2]  Bradner, S., "Key words for use in RFCs to Indicate Requirement
        Levels", BCP 14, RFC 2119, March 1997.

   [3]  Rosenberg, J., "The Session Initiation Protocol (SIP) UPDATE
        Method", RFC 3311, September 2002.



Elwell                   Expires April 16, 2007                 [Page 4]

Internet-Draft       Asserted Identity in SIP UPDATE        October 2006


   [4]  Jennings, C., Peterson, J., and M. Watson, "Private Extensions
        to the Session Initiation Protocol (SIP) for Asserted Identity
        within Trusted Networks", RFC 3325, November 2002.


Author's Address

   John Elwell
   Siemens Enterprise Communications Limited
   Technology Drive
   Beeston, Nottingham  NG9 1LA
   UK

   Phone: +44 115 943 4989
   Email: john.elwell@siemens.com




































Elwell                   Expires April 16, 2007                 [Page 5]

Internet-Draft       Asserted Identity in SIP UPDATE        October 2006


Full Copyright Statement

   Copyright (C) The Internet Society (2006).

   This document is subject to the rights, licenses and restrictions
   contained in BCP 78, and except as set forth therein, the authors
   retain all their rights.

   This document and the information contained herein are provided on an
   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
   ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
   INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
   INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.


Intellectual Property

   The IETF takes no position regarding the validity or scope of any
   Intellectual Property Rights or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; nor does it represent that it has
   made any independent effort to identify any such rights.  Information
   on the procedures with respect to rights in RFC documents can be
   found in BCP 78 and BCP 79.

   Copies of IPR disclosures made to the IETF Secretariat and any
   assurances of licenses to be made available, or the result of an
   attempt made to obtain a general license or permission for the use of
   such proprietary rights by implementers or users of this
   specification can be obtained from the IETF on-line IPR repository at
   http://www.ietf.org/ipr.

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights that may cover technology that may be required to implement
   this standard.  Please address the information to the IETF at
   ietf-ipr@ietf.org.


Acknowledgment

   Funding for the RFC Editor function is provided by the IETF
   Administrative Support Activity (IASA).





Elwell                   Expires April 16, 2007                 [Page 6]