2.7.14 Session Initiation Proposal Investigation (sipping)

NOTE: This charter is a snapshot of the 62nd IETF Meeting in Minneapolis, MN USA. It may now be out-of-date.
In addition to this official charter maintained by the IETF Secretariat, there is additional information about this working group on the Web at:

       Additional SIPPING Web Page

Last Modified: 2005-01-31


Gonzalo Camarillo <gonzalo.camarillo@ericsson.com>
Dean Willis <dean.willis@softarmor.com>
Rohan Mahy < rohan@ekabal.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: http://www.ietf.org/mail-archive/web/sipping/index.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  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 ongoing
  SIP-related development, as commonalities may indicate for general,
  reusable functionality in SIP.

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

5. Developing 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 the SIP Security
specification within RFC 3261, and additional SIP specifications
as they apply.

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
  - requirements from 3GPP for SIP 
  - 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 
  - 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)
    negotiation, and will develop requirements
    and a framework for multi-party conferencing with SIP.

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

5. SIP URI-List services
  - the working group will develop requirements for
    SIP list services mechanisms enabling a client to request that a
    server distribute a specific SIP request to a list of recipient
    URIs. The working group will develop a mechanism to transport
    list of recipient URIs (a URI-list) from a SIP client to SIP
    in conjunction with the request (a request-contained list). The
    working group will also specify mechanisms (presumed not to be
    mechanims)for storing, modifying, or retrieving a URI-list stored
    on a server (stored URI-lists). The working group will specify
    use of URI-lists with various SIP request types for which list
    services are appropriate with both stored and request-contained
    URI-lists. The working group will also develop requirements and
    specifications for a positive opt-in mechanism by which list
    servers can prevent amplification of attacks and relay abuses.

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) is related to the task
areas in a number of areas.  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
Done  Using ENUM with SIP Applications to IESG for consideration as an Informational RFC
Done  Requirements for Reuse of Connections in SIP
Done  Submit Internet-Draft on T.38 Fax Call Flows to IESG for consideration as a BCP
Done  Requirements for SIP Request History
Done  Submit Internet-Draft on Requirements for AAA Application in SIP Telephony to IESG for consideration as an Informational RFC
Done  Sip Interworking with QSIG
Done  3pcc Transcoding to IESG as Info
Jul 04  KPML to IESG as PS
Aug 04  Conferencing Requirements to IESG as Info
Aug 04  Conferencing Framework to IESG as Info
Aug 04  Conferencing Call Control-Conferencing to IESG as BCP
Sep 04  Location Requirements to IESG as Info
Done  End-to-Middle Security Requirements to IESG as Info
Sep 04  Requirements on Trait-Based Authorization to IESG as Info
Oct 04  Configuration Framework to the IESG as a PS
Oct 04  Submit Requirements and Framework for Exploders to the IESG as PS
Oct 04  Submit Opt-in/Opt-out Mechanism for Exploders to the IESG as PS
Oct 04  Submit URI List Transport Mechanism to the IESG as PS
Nov 04  Submit I-D on Ad-Hoc Conferencing using URI lists to the IESG as PS
Nov 04  Submit I-D on MESSAGE Exploders to the IESG as PS
Nov 04  Submit I-D on Multiple REFER to the IESG as PS
Nov 04  Submit I-D on Subscriptions to Ad-Hoc Resource Lists to the IESG as PS
Dec 04  Event Filtering Requirements to the IESG
Dec 04  Caller Preferences Use Cases
Dec 04  SIP Service Examples
Dec 04  Session Policy Requirements to IESG as Info
Jan 05  Session Independent Policy Mechanism to the IESG as PS
Feb 05  Transcoding with Conf Bridge to IESG as Info
Feb 05  Transcoding Framework to IESG as Info
Mar 05  Session Specific Policy Mechanism to the IESG as PS
Apr 05  Review charter with Area Directors and recharter or conclude


  • draft-ietf-sipping-service-examples-08.txt
  • draft-ietf-sipping-cc-framework-04.txt
  • draft-ietf-sipping-nat-scenarios-02.txt
  • draft-ietf-sipping-dialog-package-05.txt
  • draft-ietf-sipping-conference-package-09.txt
  • draft-ietf-sipping-3gpp-r5-requirements-00.txt
  • draft-ietf-sipping-cc-transfer-03.txt
  • draft-ietf-sipping-qsig2sip-04.txt
  • draft-ietf-sipping-config-framework-06.txt
  • draft-ietf-sipping-cc-conferencing-06.txt
  • draft-ietf-sipping-conferencing-requirements-01.txt
  • draft-ietf-sipping-conferencing-framework-04.txt
  • draft-ietf-sipping-callerprefs-usecases-03.txt
  • draft-ietf-sipping-kpml-07.txt
  • draft-ietf-sipping-app-interaction-framework-04.txt
  • draft-ietf-sipping-e2m-sec-reqs-05.txt
  • draft-ietf-sipping-reason-header-for-preemption-02.txt
  • draft-ietf-sipping-transc-3pcc-02.txt
  • draft-ietf-sipping-transc-framework-01.txt
  • draft-ietf-sipping-location-requirements-02.txt
  • draft-ietf-sipping-trait-authz-01.txt
  • draft-ietf-sipping-session-indep-policy-02.txt
  • draft-ietf-sipping-uri-services-02.txt
  • draft-ietf-sipping-uri-list-conferencing-02.txt
  • draft-ietf-sipping-uri-list-message-02.txt
  • draft-ietf-sipping-uri-list-subscribe-02.txt
  • draft-ietf-sipping-multiple-refer-02.txt
  • draft-ietf-sipping-certs-01.txt
  • draft-ietf-sipping-consent-reqs-00.txt
  • draft-ietf-sipping-consent-framework-01.txt
  • draft-ietf-sipping-toip-00.txt
  • draft-ietf-sipping-spam-00.txt

    Request For Comments:

    RFC3324 I Short Term Requirements for Network Asserted Identity
    RFC3351 I User Requirements for the Session Initiation Protocol (SIP) in Support of Deaf, Hard of Hearing and Speech-impaired individuals
    RFC3372 BCP Session Initiation Protocol (SIP) for Telephones (SIP-T): Context and Architectures
    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)
    RFC3665 BCP Session Initiation Protocol Basic Call Flow Examples
    RFC3666 BCP Session Initiation Protocol PSTN Call Flows
    RFC3680 Standard A Session Initiation Protocol (SIP) Event Package for Registrations
    RFC3702 I Authentication, Authorization and Accounting Requirements for the Session Initiation Protocol
    RFC3725 BCP Best Current Practices for Third Party Call Control in the Session Initiation Protocol
    RFC3824 I Using E.164 numbers with the Session Initiation Protocol (SIP)
    RFC3842 Standard A Message Summary and Message Waiting Indication Event Package for the Session Initiation Protocol (SIP)
    RFC3959 Standard The Early Session Disposition Type for the Session Initiation Protocol (SIP)
    RFC3960 I Early Media and Ringing Tone Generation in the Session Initiation Protocol (SIP)

    Current Meeting Report

    Minutes SIPPING WG at IETF 62

    Minutes edited by Gonzalo Camarillo
    Based on notes by Spencer Dawkins and Azita Kia
    Meeting chaired by Dean Willis, Rohan Mahy, and Gonzalo Camarillo

    THURSDAY, March 10, 2005, 0900-1130

    Topic: Agenda Bash
    by chairs

    The "Semi Regular Examples", "Multiple Dialog Usages in SIP" and "Example call flows using SIP security mechanisms" individual I-Ds were brought to the attention of the WG. The authors requested comments on them.

    Gonzalo Camarillo and Robert Sparks will coordinate the review of the Torture Tests I-D by a set of volunteers. The idea is to have the I-D fully reviewed before the next SIPit.

    The WGLC on the URI-list services I-Ds has ended, but given that these I-Ds depend on the consent work, their publication will be requested together with the consent I-Ds when these are ready.

    It was noted that the current charter and milestones are completely obsolete, despite having had changes submitted several times by the chairs and the ADs. Apparently there is some sort of process problem with the IETF web site.

    The chairs encouraged people to put work more between IETF meetings, and not only right before the meetings.

    The Location Requirements I-D has been moved to SIP.

    Topic: Configuration Framework
    Presentation led by: Dan Petrie
    Relevant document: draft-ietf-sipping-config-framework-06.txt

    The changes introduced in the latest revision of the document were presented.

    The XCAP section of the draft needs to be improved.

    There was agreement to restrict the transports supported by the framework to only HTTP/HTTPS.

    The author noted that this draft is close to be ready, and requested people to read it and send comments now that it is still possible to include them.

    Topic: Data Sets
    Presentation led by: Dan Petrie
    Relevant document: draft-petrie-sipping-profile-datasets-01.txt

    At this point of the meeting, it was noted that there are not enough people reading the I-Ds in the agenda. It was also noted that it is not realistic that people read all the drafts in the agendas of SIP, SIPPING, SIMPLE, XCON, and MMUSIC. It is clear that it is necessary to finish a few chartered items before trying to tackle new work.

    The changes made for the last revision of the I-D were presented.

    It was noted that having elements that can be registered in other contexts as text strings would cause problems. The XML schema should be designed with those registries in mind.

    More discussions needed on which elements to include in the schema. In general, elements that are not going to be used by anyone should not be included.

    Topic: Session Policies
    Discussions led by: Volker Hilt
    Relevant documents: draft-ietf-sipping-session-indep-policy-02.txt

    Discussions on which policy protocol to use. Agreement that the two options that implementors are more likely to actually implement are SUBS/NOT for user agents to obtain policies and PUBLISH, HTTP, or SUBSCRIBE to send session information to the policy server. However, clearer use cases are needed before a decision can be made.

    Topic: Consent
    Discussions led by: Gonzalo Camarillo
    Relevant documents: draft-ietf-sipping-consent-reqs-00.txt

    The WG did not have a strong opinion on how to identify translations on relays (using the Request-URI or a header). It was also suggested to explore using a URI parameter.

    There were discussions on the mandatory protocol to be used to upload permission documents: SUBS/NOTIFY plus PUBLISH vs. XCAP. It was claimed that if a SIP-based mechanism is chosen, SIP-only devices will be able to use this framework. However, XCAP supports more complex composition policies. There was no consensus in the room. Further discussions to take place on the mailing list.

    Topic: Transcoding
    Discussions led by: Gonzalo Camarillo
    Relevant documents: draft-ietf-sipping-transc-framework-01.txt

    Conferencing model vs. using Route entries. Total consensus in the room that the conferencing model should be used. The author will edit the framework accordingly and release an updated I-D defining the conference model (the current I-D has expired).

    Topic: IPv6 Transition in SIP
    Discussions led by: Gonzalo Camarillo
    Relevant documents: draft-camarillo-sipping-v6-transition-00.txt

    The IESG is requesting SIPPING to do this. Total consensus to adopt this I-D as a WG item.

    Topic: Session Border Controllers
    Discussions led by: Jani Hautakorpi
    Relevant documents: draft-camarillo-sipping-sbc-funcs-00.txt

    Both I-Ds will be merged. The resulting I-D's scope will be to document functions that existing SBCs implement and that break SIP somehow. This work will be used as input by different WGs to decide whether or not new specifications or recommendations are needed in this area.

    FRIDAY, March 11, 2005, 0900-1130

    Topic: Agenda Bash
    by chairs

    No comments from the floor.

    Topic: Conferencing Package
    Discussions led by: Orit Levin
    Relevant document: draft-ietf-sipping-conference-package-09.txt

    Still open issues. The author will discuss them with the folks that sent the WGLC comments to the mailing list and release a new version addressing them.

    Topic: Redirection Reason
    Discussions led by: John Elwell
    Relevant document: draft-elwell-sipping-redirection-reason-01.txt

    Not clear what the 302 ambiguity problem the draft attempts to resolve is. Needs to be clarified. Does it have something to do with request history? Is it only applicable to legacy (e.g., PSTN interworking) or to new applications?

    Topic: Multipart bodies
    Discussions led by: Cullen Jennings
    Relevant document: draft-jennings-sipping-multipart-00.txt

    We need to have a clear scope for the draft. That is, we do not want to have two ways to do things that are currently addressed by the SDP grouping framework (e.g., ANAT).

    Topic: Status Update HashCash & Pay
    Discussions led by: Cullen Jennings
    Relevant documents: draft-jennings-sipping-pay-01.txt

    Discussions on which of the approaches (pay or hashcash) addresses better the SPAM problem. Further discussions will take place in the mailing list.

    Topic: Event Thorttles
    Discussions led by: Aki Niemi
    Relevant document: draft-niemi-sipping-event-throttle-02.txt

    This seems to be useful for data that changes rapidly and gives the subscriber overrides. However, a document may contain several types of data, and the notifications of some of these may not need to be throttled. A filter may do the job in a better way (e.g., if his availability to receive voice calls changes, notify me at once, but if his GPS position changes, notify me only once every 10 seconds).

    The chairs will poll the list for consensus.

    Topic: LESS: Language for End System Services in Internet Telephony
    Discussions led by: Henning Schulzrinne
    Relevant document: draft-wu-iptel-less-00.txt

    The author gave a heads up for the community.

    Allison said that other communities are saying that since there is so many SIP specification, they are building their own SIP monolith. She would discourage informational publications at this point.

    Topic: Session Mobility
    Discussions led by: Henning Schulzrinne
    Relevant document: draft-shacham-sipping-session-mobility-00.txt

    The author gave a heads up for the community.


    Status and Agenda Bash
    Configuration Framework
    Schema for SIP Profile Data Sets
    Session Policies
    Consent Framework
    Transcoding Framework
    IPv6 Transition
    SBC Functions
    Conferencing Package
    Status Update HashCash & Pay
    Event Throttles
    LESS: Language for End System Services in Internet Telephony
    Session Mobility
    Redirection Reason