Minutes, SIPPING WG, 59th IETF

Notes by Brian Rosen, Spencer Dawkins, and Cyrus Shaoul
Minutes edited by Gonzalo Camarillo
Meetings chaired by Gonzalo Camarillo, Rohan Mahy, and Dean Willis

Session 1, Monday, March 1, 2004, 0900-1130

Topic: Status
Slides presented: pres-sip-ietf59-chairs.ppt
Discussions led by: Chairs

The draft tracker in the supplemental web page is up to date.

Issue: we are not open to new ideas and it takes a long time to finish the drafts we are already working on.
Discussion: Use deadlines.
Discussion: Force people to help others (e.g., review documents) before they get their work in the charter. Note that this may make it even more difficult for newcomers to bring their work to SIPPING.
Conclusion: Chairs will be working on these issues. In addition, they will organize an interim meeting before the 60th IETF.

Topic: Session Policies
Relevant documents:
Slides presented: pres-ietf59-hilt-session-policy.ppt
Discussions led by:  Volker Hilt

Issue: Session independent policy data and configuration data will use the same delivery mechanism.
Conclusion: XCAP package, the configuration framework, and the session independent policy work need to be aligned. Once they are aligned, we will be able to consider taking the session independent policy work as a WG item.

Issue: Two possible models for the session specific policy work: piggyback model and re-direct model.
Discussion: Both models will most likely need some type of end-to-middle or middle-to-end security.
Conclusion: More work needed before we can decide which model to choose.

Topic: The Dialog Package
Relevant document: draft-ietf-sipping-dialog-package-04.txt
Slides presented: pres-mahy-sipping-ietf59-dialog-pkg.ppt
Discussions led by: Rohan Mahy

Issue: callee-caps feature tag for interactivity.
Discussion: Media feature tags are usually static. Interactivity has to do with the application, rather than with the media.

Topic: End-To-Middle
Relevant documents:
Slides presented: pres-sipping-ono-IETF59-e2m.ppt
Discussions led by: Kumiko Ono

Issue: We need to find use cases where e2m security is needed.
Discussion: Emergency may not be a good use case, because proxies may need the information for routing, and the UA does not know those proxies in advance.
Location outside emergency calls would be a good use case.
Open question: Should we allow proxies to remove bodies that were only addressed to them?

Topic: Real-Time Text Conversation Using SIP
Relevant document: draft-manyfolks-sipping-toip-01.txt
Slides presented: pres-ietf59-wijk-toip.ppt
Discussions led by: Arnoud van Wijk

Issue: what is special about text gateways that is not covered by the transcoding and conferencing frameworks?
Conclusion: Authors will send scenarios to XCON.

Topic: Q.SIG SIP Call Transfer
Relevant document: draft-rey-sipping-qsig2sip-transfer-00.txt
Slides presented: pres-ietf59-rey-qsig2sip-xfer.ppt
Discussions led by: Jean-Francois Rey

Conclusion: The WG can address SIP-related open issues, but will not take this work as a WG item. There is a lack of expertise and interest.

Topic: S/MIME Certificates in SIP
Relevant document: draft-jennings-sipping-certs-02.txt
Slides presented: pres-sipping-jennings-IETF59-Certs-v2.ppt
Discussions led by: Cullen Jennings

Issue: is this the same thing as identity?
Discussion: we need to compare both approaches, because we do not want two mechanisms to do the same thing.
Discussion: we need a deployabe solution.

Topic: RTCP Summary Report Event Package
Relevant document: draft-johnston-sipping-rtcp-summary-02.txt
Slides presented: pres-ietf59-johnston-rtcp.ppt
Discussions led by: Alan Johnston

Conclusion: the authors should explain the difference between this work and RMON.

Topic: State Update
Relevant documents:
Slides presented: pres-sipping-elwell-update-ietf59.ppt
Discussions led by: John Elwell

Conclusions: we need more requirements to underand how this related to security and identity.

Session 2, Wednesday, March 3, 2004, 1300-1500

Topic: Application Interaction Design Team and Registration Event Package
Relevant document: draft-ietf-sipping-app-interaction-framework-01.txt
Slides presented: pres-sipping-jdr-ietf59.ppt
Discussions led by: Jonathan Rosenberg

Issue: Matching REFERs to associated components.
Conclusion: we need an explicit correlator.

Issue: The current version of the draft, which is in AUTH48, does not allow adding path information.
Discussion: adding a URI to contact, use "unknown" XML elements...
Conclusion: Jonathan posts a concrete proposal to the list.

Topic: KPML
Relevant document: draft-ietf-sipping-kpml-02.txt
Slides presented: pres-ietf59-sipping-burger-kpml.ppt
Discussions led by: Eric Burger

Issue: should the draft use GRUUs?
Conclusion: yes, it should use GRUUs.

Topic: SIP Conferencing Design Team
Relevant documents:
Slides presented: pres-ietf59-sipping-johnston-conf.ppt
Discussions led by: Alan Johnston

Conclusion: we need to understand how to use nicknames not only in conferences, but in a wider range of situations.

Topic: Transcoding Design Team
Relevant document: draft-camarillo-sipping-transc-b2bua-01.txt
Slides presented: pres-ietf59-sipping-camarillo-transcoding.ppt
Discussions led by: Gonzalo Camarillo

Conclusion: Consensus on WGLCing draft-ietf-sipping-transc-3pcc-00.txt

Issue: should we invoke the transcoder as if it was a conference (current approach) or using Route entries?
Discussion: no consensus on which is the best approach.

Topic: Location Conveyance Requirements
Relevant document: draft-ietf-sipping-location-requirements-00.txt
Slides presented: pres-ietf59-sipping-polk-location.ppt
Discussions led by: James Polk

Issue: Location for emergency calls. Should it be included even if it may be wrong?

Topic: SIP Emergency
Relevant documents:
Slides presented: pres-ietf59-sipping-henning-emergency.ppt
Discussions led by: Henning Schulzrinne

Conclusion: Continue discussions in the mailing list.

Topic: Exploders and Multiple REFER
Relevant documents:
Slides presented: pres-ietf59-sipping-camarillo-exploders.ppt
Discussions led by: Gonzalo Camarillo

Conclusions: update uri-list draft so that it defines a general mechanism to transport uri lists using headers or URI parameter. Each application will choose where to place the uri list. Write documents explaining how to use uri lists at least for conferencing and presence. Make ad-hoc management a general mechanism that works with different resources. Clarify the requirements (Cullen Jennings will work together with Gonzalo Camarillo on clarifying them).

Discussion: We will decide whether or not to tackle multiple-REFER when the drafts above have been updated and understood.

Topic: REFER Extensions
Relevant document: 
Slides presented: pres-ietf59-sipping-audet-refer.ppt
Discussions led by: Francois Audet

REFER Extensions:
Discussion: we need use cases for each extension to understand their appropriateness.
Conclusion: tackle each extension separately. Their maturity levels are different.

REFER for Call Control:
Discussion: REFER may not be the right tool for this.
Conclusion: Authors look at the MBUS work done in MMUSIC.

Ad-Hoc Meeting on E2M and M2E Security, Session Policies, and Location

Topic: For which applications do we need e2m and m2e security? We need use cases.
e2m: location conveyance (Non-emergency location based call routing), logging services, and session policies.
Open question: how does identity fit here?

m2e:  request history, identity, and Session policy (in piggyback model).
Open question: if proxies cannot insert bodies, how do we secure request history?

Topic: Session Policies
Conclusion: we want to have session independent policies, and they should be aligned with the configuration framework.

Discussion: Mechanisms for session specific policies can get complicated. We need to agree which requirements we want to meet and which ones we do not want to meet. Three levels:
  1. Request
  2. Response
  3. Asynchronous (this may be implemented using session independent policies)
Open question: how do UAs disclose session information (e.g., IP addresses being used) to the policy server? Is it SIP using the piggybacking model, SIP using the re-direct model, or a different protocol?

Action Items