2.8.14 Session Initiation Proposal Investigation (sipping)

In addition to this official charter maintained by the IETF Secretariat, there is additional information about this working group on the Web at:

       http://softarmor.com/sipping -- Additional SIPPING Web Page
NOTE: This charter is a snapshot of the 58th IETF Meeting in Minneapolis, Minnesota USA. It may now be out-of-date.

Last Modified: 2003-10-16

Gonzalo Camarillo <gonzalo.camarillo@ericsson.com>
Dean Willis <dean.willis@softarmor.com>
Rohan Mahy <rohan@cisco.com>
Transport Area Director(s):
Allison Mankin <mankin@psg.com>
Jon Peterson <jon.peterson@neustar.biz>
Transport Area Advisor:
Allison Mankin <mankin@psg.com>
Mailing Lists:
General Discussion: sipping@ietf.org
To Subscribe: sipping-request@ietf.org
In Body: (un)subscribe
Archive: www.ietf.org/mail-archive/working-groups/sipping/current/maillist.html
Description of Working Group:
The Session Initiation Protocol Project INvestiGation (SIPPING) working group is chartered to document the use of SIP for several applications related to telephony and multimedia, and to develop requirements for any extensions to SIP needed for those applications. Such requirements will be referred to the SIP working group for development of any new SIP method or header. Guiding principles for the performance of SIPPING's work will include:

1. Documenting the requirements of specific chartered tasks.

2. Documenting the usage of SIP to solve real problems that need to be solved in a standardized way.

3. Looking for commonalities among the chartered tasks and other ongoing SIP-related development, as commonalities may indicate need for general, reusable functionality in SIP.

4. Describing the requirements for any extension determined to be needed, and handing them to the SIP WG.

5. Develop procedures and requirements for configuration and delivery of SIP User Profiles

Besides performing needed specification of several applications of SIP, SIPPING can be seen as also working out use cases that clarify the role of SIP in the Internet, and help to ensure that Occam's razor is appropriately applied to SIP usage.

The security of all the deliverables will be of special importance. The technology for security will be keyed from a SIP security specification developed (in progress now) by the SIP Working Group.

The specific tasks for SIPPING will be:

1. PSTN and/or 3G telephony-equivalent applications that need a standardized approach

- informational guide to common call flows

- support for T.38 fax

- requirements from 3GPP for SIP usage

- framework of SIP for telephony (SIP-T)

- call transfer and call forwarding

- AAA application in SIP telephony

- mapping between SIP and ISUP

2. Messaging-like applications of SIP -

- support for hearing-/speech-impaired calling

- development of usage guidelines for subscribe-notify (RFC 2848, SIP events) to ensure commonality among applications using them, including SIMPLE WG's instant messaging.

3. Multi-party applications of SIP

- the working group will review a number of technical pieces including call transfer, subscribe-notify, SIP features negotiation, and session description protocol (SDP) capability negotiation, and will develop requirements and an initial design or framework for multi-party conferencing with SIP.

4. SIP calling to media servers

- the working group will develop a requirements draft for an approach to SIP interaction with media servers. An example is whether a voicemail server is just a box that a caller can send an INVITE to.

At a later time, the working group and chairs may request of the Area Directors that new tasks be added to the charter. Such additions to the charter will require IESG approval.

The group will work very closely with SIP working group. The group will also maintain open dialogue with the IPTEL working group, whose Call Processing Language (CPL) related to the task areas in a number of ways. The group will also coordinate closely with SIMPLE, AAA, and MMUSIC (SDP development).

SIPPING will also ensure compatibility with the work done by the now concluded PINT working group. SIPPING will encourage active participation from the Distributed Call Signaling (DCS) Group of the PacketCable Consortium for distributed telephony services, 3GPP, 3GPP2, and several ITU-T study groups.

Goals and Milestones:
Done  Submit Internet-Draft on SIP-Telephony Framework to IESG for consideration as a BCP
Done  Submit Internet-Draft on ISUP-SIP Mapping to IESG for consideration as Proposed Standard
Done  Submit Internet-Draft on Requirements for use of SIP to support telephony for the Hearing-Impaired to IESG for consideration as an Informational RFC
Done  Submit SIP 3rd party call control to IESG for consideration as BCP
Done  Submit Internet-Draft on 3G Requirements to IESG for consideration as an Informational RFC
Done  Submit Internet-Draft on Mapping ISUP Overlap Signaling to SIP to IESG for consideration as a Proposed Standard
Done  Submit Internet-Draft on Usage Guideline for Events (Subscribe-Notify) to IESG for consideration as an Informational RFC
Done  Submit Internet-Drafts Basic and PSTN Call Flows to IESG fro consideration as BCPs
Done  Requirements for Content Indirection in SIP
Done  Submit Message Waiting SIP event package to IESG for consideration as PS
Mar 03  Submit Internet-Draft on Call Transfer using REFER to IESG for consideration as a BCP
Mar 03  Using ENUM with SIP Applications to IESG for consideration as an Informational RFC
Apr 03  Submit Call Info SIP event package to IESG for consideration as PS
Apr 03  Requirements for Reuse of Connections in SIP
Jun 03  Submit Internet-Draft on T.38 Fax Call Flows to IESG for consideration as a BCP
Jun 03  Submit Conf Info SIP event package to IESG for consideration as PS
Jun 03  Requirements for SIP Request History
Jun 03  Event Package for User Configuration Profiles
Aug 03  Submit Internet-Draft on Multi-Party/Conferencing Framework to IESG for consideration as an Informational RFC
Done  Submit Internet-Draft on Requirements for AAA Application in SIP Telephony to IESG for consideration as an Informational RFC
Oct 03  Sip Interworking with QSIG
Nov 03  Review charter with Area Directors and recharter or conclude
Nov 03  Submit Internet-Draft Torture Tests to IESG for Consideration as Informational
  • - draft-ietf-sipping-e164-04.txt
  • - draft-ietf-sipping-service-examples-05.txt
  • - draft-ietf-sipping-cc-framework-03.txt
  • - draft-ietf-sipping-3pcc-05.txt
  • - draft-ietf-sipping-mwi-03.txt
  • - draft-ietf-sipping-dialog-package-03.txt
  • - draft-ietf-sipping-conference-package-02.txt
  • - draft-ietf-sipping-pstn-call-flows-02.txt
  • - draft-ietf-sipping-basic-call-flows-02.txt
  • - draft-ietf-sipping-torture-tests-01.txt
  • - draft-ietf-sipping-req-history-04.txt
  • - draft-ietf-sipping-aaa-req-03.txt
  • - draft-ietf-sipping-3gpp-r5-requirements-00.txt
  • - draft-ietf-sipping-reg-event-00.txt
  • - draft-ietf-sipping-qsig2sip-03.txt
  • - draft-ietf-sipping-config-framework-01.txt
  • - draft-ietf-sipping-cc-conferencing-02.txt
  • - draft-ietf-sipping-conferencing-requirements-00.txt
  • - draft-ietf-sipping-conferencing-framework-01.txt
  • - draft-ietf-sipping-session-policy-req-00.txt
  • - draft-ietf-sipping-callerprefs-usecases-00.txt
  • - draft-ietf-sipping-kpml-01.txt
  • - draft-ietf-sipping-event-throttle-reqs-00.txt
  • - draft-ietf-sipping-early-media-00.txt
  • - draft-ietf-sipping-app-interaction-framework-00.txt
  • - draft-ietf-sipping-e2m-sec-reqs-00.txt
  • Request For Comments:
    RFC3351 I User Requirements for the Session Initiation Protocol (SIP) in Support of Deaf, Hard of Hearing and Speech-impaired individuals
    RFC3372BCPSession Initiation Protocol (SIP) for Telephones (SIP-T): Context and Architectures
    RFC3324 I Short Term Requirements for Network Asserted Identity
    RFC3398 PS Integrated Services Digital Network (ISDN) User Part (ISUP) to Session Initiation Protocol (SIP) Mapping
    RFC3485 PS The Session Initiation Protocol (SIP) and Session Description Protocol (SDP) Static Dictionary for Signaling Compression (SigComp)
    RFC3578 PS Mapping of of Integrated Services Digital Network (ISUP) Overlap Signalling to the Session Initiation Protocol (SIP)

    Current Meeting Report

    Minutes, SIPPING WG, IETF 58

    Notes by Brian Rosen and Francois Audet
    Minutes edited by Gonzalo Camarillo
    Meetings chaired by Gonzalo Camarillo, Rohan Mahy, Dean Willis

    Session 1, Tuesday November 11, 2003 0900-1130

    Topic: Agenda

    Agenda accepted as previously posted.

    Topic: Announcements and Status

    Chairs mention that they will provide an updated list of milestones for the working group in the second session. MSCML will proceed as an informational individual contribution. There are still some security concerns with the Q.SIG work, but they will probably be resolved soon. The chairs mentioned the existance of draft-manyfolks-sipping-tiop.

    Slides presented reviewing status of working group documents.

    Topic: Application Interaction

    Relevant document:

    Slides presented

    Discussion led by Jonathan Rosenberg

    Issue: how to deliver DTMF. The current draft proposes two different mechanisms, one based on REFER and HTTP for presentation capable UAs and the other based on SUBSCRIBE/NOTIFY for presentation free UAs.
    Discussion: It should still be possible to use KPML with other transport mechanisms. We need to think of the security implications of this work. Are servers supposed to be in the signalling path or can they obtain the scripts using some other means, such as the dialog package?
    Conclusion: Strong consensus on documenting both mechanisms and provide recommendations on how to use them.

    Topic: Event Package for DTMF Signals

    Relevant document:

    Slides presented:

    Discussion led by Joe Zebarth

    Presentation: a mechanism to transport DTMF to implement prepaid services is needed soon (end of Q1 2004.) The mechanism proposed (an event package) is complementary to KPML because it moves the processing intensity from the Notifier to app server.
    Discussion: The real difference between KMPL and this approach is the number of events per digit.
    Conclusion: T1 writes a liaison to the IETF indicating their timeframe. If it is possible to meet their deadlines with KPML, the WG prefers not to duplicate standards track work.

    Topic: Key Press Stimulus Protocol

    Relevant document:


    Slides presented:

    Discussion led by Eric Burger

    Issue: is the SUBSCRIBE/NOTIFY mechanism OK?
    Conclusion: no onjection to immediate NOTIFY with empty body.
    Issue: three ways to specify digit maps.
    Discussion: requiring three mechanisms is too much. A negotiation using an Accept-like mechanism could be appropriate.
    Conclusion: continue discussions on the list.

    Topic: Conferencing Design Team Report

    Relevant Documents:

    Slides presented:

    Discussion led by Alan Johnston

    Presentation: Framework needs one more revision to align with GRUU. Conference package needs some work to align with XCON.
    Issue: side bars.
    Conclusion: It will probably be an XCON document. The framework will talk about them.

    Topic: Transcoding Design Team

    Relevant documents:

    Slides presented:

    Discussion led by Gonzalo Camarillo

    Conclusion: strong consensus on adding milestones for the framework, the conf bridge model, and the 3pcc model. Strong consensus on adopting the framework and the 3pcc documents as WG items for those milestones. The design team prefers to wait until the exploders work is completed before asking the WG to adopt the conf bridge model as a WG item.

    Topic: Emergency Calls Design Team

    Relevant document:
    Slides presented:

    Discussion led by Tom Taylor

    Issue: Intermediaries need to insert location information (e.g., phones without emergency support and phones not recognizing emergency calls.)
    Discussion: Should this intermediaries be existing SIP entities (e.g., proxies or B2BUAs) or can they be something special?
    Conclusion: more discussions needed.
    Comment: NENA has two WGs working on these issues and will provide SIPPING with requirements.
    Comment: hearing impaired users need to be taken into account.

    Topic: Event Package for User Configuration Profiles

    Relevant document:
    Slides presented:

    Discussion led by Dan Petrie

    Issue: can we use XCAP?
    Discussions: There are other protocols that could do the job as well, and the initial idea was to be protocol agnostic.
    Comment: Are we talking into consideration wireless issues?
    Issue: which security mechanisms need to be mandatory to implement?
    Conclusion: Organize a conference call and report to the list.

    Topic: Intermediary Session Policies in SIP

    Relevant documents:
    Slides presented:

    Discussion led by Volker Hilt

    Issue: two-pass model vs. three-pass model.
    Conclusion: two-pass model is the way to go.
    Conclusion: strong negative on sending the documents to SIP. They still need more work.

    Topic: Reason Header for Preemption

    Relevant document:
    Slides presented:

    Discussion led by James Polk

    Issue: use a single or multiple namespaces.
    Conclusion: use a single namespace.
    Conclusion: progress as an individual contribution.

    Topic: Location Conveyance Requirements

    Relevant document:

    Discussion led by Brian Rosen

    Issue: should we use bodies or headers.
    Issue: we need to analyze the security implications of this work.
    Conclusion: strong consensus on adding a milestone for this work and to take this document as a WG item for that milestone.

    Topic: Transfer Issues

    Relevant document:
    Slides presented:

    Discussion led by Dan Petrie

    No conclusions.

    Session 2, Thursday, November 13, 2003, 1530-1730

    Topic: Agenda

    Jonathan Rosenberg will present NAT scenarios in MMUSIC instead.
    Chairs presented an updated list of milestones for the WG.

    Topic: Requirements for end-to-middle security

    Relevant document:
    Slides presented:

    Discussion led by Kumiko Ono

    Presentation: difference between e2m and m2e. e2m requires discovery.
    Issue: manipulation of bodies by intermediaries.
    Discussions: a re-direction model where the UA is the one that inserts the body might be an alternative, although it may introduce long delays.

    Topic: Requirements for e2m and m2e

    Relevant document:
    Slides presented:

    Discussion led by Mary Barnes

    Issue: shall we look at m2m as well?
    Issue: trust model.
    Issue: mechanism to challenge intermediaries.
    Issue: intermediaries manipulating message bodies.
    Conclusion: further discussions in the mailing list needed.

    Topic: Role(trait)-Based Authorization

    Relevant document:

    Discussion led by Jon Peterson

    Conclusion: strong consensus of making it a WG item.

    Topic: On-demand Access Authorization

    Relevant document:
    Slides presented:

    Discussion led by Dirk Trossen

    Discussion: XCAP meets many, but not all the requirements.
    Conclusion: the work is relevant, but we need more convincing use cases.

    Topic: Early Media

    Relevant documentss:
    Slides presented:

    Discussion led by Gonzalo Camarillo

    Conclusion: strong consensus on making the early media disposition type draft a WG item.

    Topic: IPv4/IPv6 Translators in 3GPP Networks

    Relevant documents:
    Slides presented:

    Discussion led by Gonzalo Camarillo

    Discussion: This work should take place in SIPPING with support from v6ops.
    Conclusion: group of volunteers will help with this work: Marcus Brunner, Roni Even, Keith Drage, and Dirk Kutscher.

    Topic: Exploders

    Relevant document:
    Slides presented:

    Discussion led by Gonzalo Camarillo

    Discussion: this is definitively interesting, but the WG is too busy to tackle more work right now.
    Conclusion: continue mailing list discussions.

    Topic: Dialog Event Package

    Relevant document:
    Slides presented:

    Discussion led by Rohan Mahy

    Presentation: many changes introduced in the last revision of the document. It needs substantial review.
    Discussion: Rohan Mahy will send in two weeks an example of how people can present that they are busy doing something.
    Discussion: need to clarify what people mean by "hold indicator".
    Conclusion: further discussions to the mailing list.

    Topic: SIP Torture Test

    Relevant document:
    Slides presented:

    Discussion led by Robert Sparks

    Presentation: lots of changes introduced in the last revision. Review needed.
    Conclusion: we gathered volunteers to review all the messages.

    Topic: SIP Load Management

    Relevant document:
    Slides presented:

    Discussion led by Robert Sparks

    Conclusion: strong consensus on the fact that this is interesting work. Let us keep in on the list for now.

    Topic: Even Notification Throttling

    Relevant document:
    Slides presented:

    Discussion led by Aki Niemi

    Discussion: this is important work for SIMPLE.
    Issue: should we send this to SIP?
    Conclusion: Folks should send their concerns to the list if they believe this should not be sent to SIP. If concerns are small enough, this will be moved SIP. Otherwise, it will stay in SIPPING longer.

    Topic: RTCP Summary Report Delivery

    Relevant document:
    Slides presented:

    Discussion led by Alan Clark

    Discussion: scope should be clarified. Does this only apply to VoIP?
    Discussion: do entities need to report about both directions, send and recv?


    1) Receive a liaison from T1 and see whether or not KPML can meet their deadlines.

    2) Chairs to discuss with ADs adding milestones for the transcoding framework, the conf bridge model, and the 3pcc model.

    3) Chairs to discuss with ADs making draft-camarillo-sipping-transc-3pcc and draft-camarillo-sipping-transc-framework WG items.

    4) Dan Petrie organizes a conference call on XCAP usage for configuration.

    5) Chairs to discuss with ADs adding milestone for the location conveyance requirements.

    6) Chairs to discuss with ADs making draft-polk-sipping-location-requirements a WG item.

    7) Chairs to discuss with ADs adding milestone for role based authentication.

    8) Chairs to discuss with ADs making draft-peterson-sipping-role-authz a WG item.

    9) Dirk Trossen to provide the WG with use cases on on-demand access authorization.

    10) Chairs to discuss with ADs adding milestone for early media disposition type or use the general early media milestone for this.

    11) Chairs to discuss with ADs making draft-camarillo-sipping-early-disposition a WG item.

    12) Chairs to make sure that Marcus Brunner, Roni Even, Keith Drage, and Dirk Kutscher help with the IPv4/IPv4 translators in 3GPP networks work.

    13) Chairs to have volunteers review the SIP torture tests.

    14) Chairs to check whether or not there are relevant concerns on the Event Notification Throttling work. Otherwise, send it to SIP.


    A SIP Event Package for DTMF Event Monitoring
    SIP Session Policies
    App Interaction Framework
    Emergency Calling Services
    Transcoding Design Team
    Reason Header for Preemption
    Update on SIP Conferencing
    Transfer Issues
    Event Package for User Profiles
    IPv6-IPv4 Translation mechanism for SIP-based services in 3GPP Networks
    Requirements for SIP Exploder Invocation
    Early Media
    On-Demand Access Authorization for SIP Event Subscriptions
    RTCP Summary Report Delivery to SIP Third Parties
    NAT Scenarios
    Requirements for end-to-middle security for SIP
    Event Notification Throttles
    The Dialog Package
    A Mechanism to Secure SIP Information inserted by Intermediaries
    SIP Torture Tests
    SIP Load Management