Minutes, SIPPING WG, IETF 57
Notes by Tom Taylor, AC
Mahendran, and Hisham Khartabil
Minutes edited by Dean Willis
Chat room moderation by Brian Rosen
Meetings chaired by Gonzalo Camarillo, Rohan Mahy, Dean Willis
Session 1, July 14, 2003 1930-2200
==================================
Topic: Agenda
---------------------
Agenda accepted as previously posted.
Topic: Announcements and Status
----------------------------------
Chairs mentoin the SIP device reqts ad hoc 10-11 am Thur room J241/1,
and that the QoS promotion scheme draft will be discussed in Friday's
TSVWG meeting.
Slides presented reviewing status of working group documents.
pres-chairs-SIPPING-WG-status-ietf-57.ppt
Topic: SIP to QSIG Mapping
------------------------------
Relevant document:
draft-ietf-sipping-qsig2sip
Slides presented
pres-elwell-qsig2sip-ietf-57.ppt
Discussion led by John Elwell
Issue: We need more qualified reviewers for this work. A hand-poll
taken in the room indicated about a dozen people claiming to be familar
with QSIG. We discussed possibly working with external SDOs on
this. Discussion indicated that ECMA is the likely SDO. John Elwell
took the action item of providing a list of ECMA contacts to Allison
Mankin.
No conclusion.
Actions: Francois Audet to formally review document.
Topic: Dialog Package
-----------------------
Relevant document:
draft-ietf-sipping-dialog-package
Slides presented:
pres-rosenberg-dialog-pkg-ietf-57.ppt
Discussion led by Jonathan Rosenberg
Status: Went through WGLC. Minor comments incorporated.
Unable to
restrict a particular XML type in XML -- has only the accompanying text
to provide the
constraint.
Issue: extensions proposed (Sean Olson). Question: what to do
with them? Extend scope of main package, reject them, or document
them separately?
Issue: "on hold". Not clear what "on hold" means, since media can
flow anyway. Suggestion that this isn't a dialog state.
Conclusion: Rough consensus that we are not ready to advance the dialog
package at
the present time. Concerned parties instructed to discuss and
report back to
Thursday mtg.
Topic: Discussion of Configuration Issues
------------------------------------------
Relevant documents:
draft-ietf-sipping-config-framework
draft-ietf-sipping-ua-prof-framewk-reqs
draft-ietf-simple-xcap-package
Slides presented:
pres-petrie-config-fw-issues-ietf-57.ppt
pres-mahy-config-issues-ietf-57.ppt
Some open issues w/ profiles. No discussion. No conclusion on
framrework or profiles.
Issue: potential conflict between XCAP package (SIMPLE work item) and
sip-config. XCAP fits into framework: config retrieval, change notif,
config upload. Differences in many details. Do they share the same
requirements? Do they share the same
solution? Should they be unified?
Proposal to unify led to comment that config is a much more general
problem -- it may not be reasonable to use SIP for notifications in
view of a more general
model coming perhaps out of netconf. This may reflect the views
of a
number of people in the IETF at large. We will need to have a
clear explanation of
scope.
Key point: all of the entities involved have SIP addrs. Fairly
tightly scoped.
Proposal: merge or reorg the two drafts. Need an author
w/more cycles. Poll indicated rough consensus in favour, with
some hums opposed. Locus of work to be
discussed w/ ADs, noting two different areas are involved.
Conclusion: Chairs to discuss with ADs.
Topic: Session Policy and Middle Box Issues
----------------------------------------------
Relevant Document:
draft-ietf-sipping-session-policy-req-00.txt
Discussion led by Jonathan Rosenberg
Issue: Dynamic vs static policies
-- Allison: not necessarily either/or
-- Jonathan just concerned to eliminate unnecessary reqts
-- CALEA an arg against dynamic policies
Rohan volunteers to work on mechanism if he has some help.
Questions on reqt for enforcement of policy. Audience asked to
review text and
submit desired changes.
No conclusion.
Editors note: 3GPP is expecting some results here.
Topic: URI Leasing and GRUUS
----------------------------------
Relevant document:
draft-rosenberg-sipping-lease-00.txt
An informal group met prior to this meeting. They noted that embedded
route headers prevent proxy application of
policy and user services, and that leasing has a couple of other
advantages.
This groups conclusion is that leasing seems to be the way to go.
There appear to be some open issues wrt GRUU grants. The author will
add requirement that
leasing be stateless to the requirements doc.
Conclusion: Agreed that requirements shall address stateless leasing.
Consensus that work will continue with leasing model at this time.
Topic: Firewall and NAT Traversal
------------------------------------
Relevant Document:
draft-rosenberg-sipping-ice-00.txt
Slides presented in:
pres-rosenberg-sipping-nat-stuff-ietf-57.ppt
Status report
ice-01 addresses concerns raised in IETF 56
-- backward compatibility
--- case that breaks bkwd compatibility is multihomed
host. alt framework vs. alt attribute being taken into off-line
discussion
ice-01 has ~50 pages of example flows -- proposed replacement of
sipping-nat-scenarios
-- ice algorithm works out
-- troublesome case is v4-v6
-- need add call flow between ice and non-ice hosts
Question from chair: if Jonathan adds the required cases, is this a
sufficient
replacement for what we have now in the sipping-nat-scenarios document?
Consensus is that it is adequate, provided that we add text to allow
alternate approaches (such as ALG, MIDCOM) and add cases for MSRP
relay. Francois Audet volunteered to send text relating to alternate
approaches.
Process open issues:
1. Do we proceed, and if so, in which WG?
-- main ice behaviour -- mmusic?
-- SDP extensions -- mmusic
-- preconditions -- if people care, would go to sip
(poss mmusic)
-- usage scenarios -- repl sipping-nat-scenarios -- sipping
Conclusion: Hums indicated a consensus to do core ICE behavior and SDP
changes in MMUSIC, usage scenarios in SIPPING, and preconditions work
in SIP if needed.
Chairs are to discuss division of work with ADs.
Topic: Adding Realm Identifier for Private Addresses
------------------------------------------------------
Relevant Document:
draft-audet-sipping-add-realm-00.txt
Slides presented in:
pres-audet-sipping-add-realm-ietf-57.ppt
Notes: Adds explicit realm identifier for private (i.e. "local")
addresses into SDP.
Useful in case both endpoints have a priori knowledge that they are in
the same
realm -- can avoid ICE. Need to configure realm only if multiple media
terminations behind the
same NAT which will communicate with each other. Proposes SDP
attribute. Configuration mech out of scope of current draft.
Discussion on network toplogy and applicability indicated that some
additional clarity is needed. How does this relate to
phone-context?
Conclusion: Requires further list dicussion. Burden of proof is
on Francois to say it
is worth varying from general application of ICE.
Topic: Open Issues from Conferencing Design Team
-----------------------------------------------------
Relevant documents:
draft-ietf-sipping-conferencing-framework
draft-ietf-sipping-cc-conferencing SIP
draft-ietf-sipping-conferencing-requirements
Slides presented in:
pres-levin-conf
team-update-ietf-57.ppt
Discussion led by Orit Levin
Status: Conceptual issues
resolved: basic conf by SIP, adv would use XCON (they hope).
Design team work is almost complete and they welcome general
comments. If XCON forms a working group, it may be possible to
reduce the scope of draft-ietf-sipping-conferencing-requirements to
"just the SIP requirements."
Open issues with draft-ietf-sipping-conferencing-requirements: Focus
discovery.
Open issues with draft-ietf-sipping-cc-conferncing: add details for
selected msgs in presented call flows, or move into sip draft for
mechanisms.
Open issues with draft-ietf-sipping-conference-package: Needs another
rev e.g. re sidebar conversations Looking to future draft on
implementation of sidebar
Topic: Open Issues from Transcoding/Deaf Design Team
---------------------------------------------------------
Relevant Document:
draft-camarillo-sip-deaf-02.txt
Slides presented in:
pres-camarillo-transcoding-emergency.ppt
Discussion led by Gonzalo Camarillo.
Status: Resuming design team meetings. Transcoding has dependencies
which may be isolated in a separate draft.
No conclusion.
Topic: Report from Energency Calling Design Team
----------------------------------------------------
Slides presented in:
pres-camarillo-transcoding-emergency.ppt
Discussion led by Gonzalo Camarillo
Status: Scenarios doc to appear within a couple of weeks.
Topic: Requirements for SIP Service Configuration
---------------------------------------------------
Note: This has some bearing on 3GPP's use of SIP.
Proposal: Extend config framework to include service info.
Open issue: Which server to contact for data manipulation (XCAP)?
Open issue: Download conference-factory URI for automatic conf creation
No conclusion.
Session 2, Thursday, July 17, 2003, 1300-1500
=====================================
Topic: Agenda and Status
----------------------------------
Review requested for new digest-AKA draft.
Topic: Open Issues from Application Interaction Design Team
---------------------------------------------------------------
Relevant Documents:
draft-rosenberg-sipping-app-interaction-framework-00
draft-jennings-sip-app-info-01
draft-burger-sipping-kpml-02
Slides presented in:
pres-rosenberg-sipping-day2-ietf-57.ppt
Discussion led by Jonathan Rosenberg
Issues:
KPML DTMF reporting problem
• INFO ( Cannot work within call dialog)
• NOTIFY w implicit subscription
• Explicit subscription from application
• HTTP
• New method?
• MESSAGE
Design team reluctantly chose MESSAGE!
Proposal:
• Continue to hammer out the open issue
• Adopt the framework and KPML as SIPPING items.
Conclusions:
a) Hum on “This is interesting work and that we should adopt the
framework” – Accepted.
b) Hum on “All who believe KPML should be accepted as WI” – accepted.
c) Chairs will ask the AD to adopt framework and KPML as WG items.
d) The KPML reporting issue will be discussed more on the mailing list.
Topic: Early Media
-------------------
Relevant document:
draft-camarillo-sipping-early-media-02.txt
Discussion led by Gonzalo Camarillo
Status:
Changes since last rev include clarifying which features are specific
to early media and which ones to SIP and other editorial changes.
To be done: Align application server model section with app design team
No conclusions.
Topic: Conveying Tones in SIP
-------------------------------
Relevant document:
draft-mahy-sipping-tones-00.txt
Discussion led by Rohan Mahy
Issue: How to provide tones?
Options discussed include
1) In RTP
a. Speech codec – poor choice
b. Using audio/tone AVT payload
c. Using audio/telephone-event
AVT payload
2) Referenced externally by URI with Alert-info or
message/external
3) In a SIP header (proposed back in Nov 2000)
4) In the session description
5) In SIP body
a. Use Content-Disposition: Render
If in a body, What body types are available?
1) Traditional
a. Wav, au, mp3
2) Audio/tone
3) Audio/tone-info+xml
4) Many more…
5) XML based: Audio/tone-info+xml
Discussions:
-Use of midi was suggested by Henning.
Conclusions: The issue on tones will be discussed more on the list.
Topic: Network Announcements
---------------------------------
Relevant document:
draft-burger-sipping-netann-06
Discussion led by Eric Burger.
Open Issues:
1) Early media:
Punt. No definitions for early
media
Makes 487/409 problem go away.
2) Media on hold
Punt. Local matter
3) Multiple media streams
Punt. Netann is about objects not
streams
Only composite objects for
multimedia
4) VoiceXML keyword without value
Generate 404 with explanation.
Poll taken for adoption as a working group item indicated little
support. However, the work is not seen as being in opposition to
chartered work.
Conclusions: The draft will be submitted for publication as an
individual contribution.
Topic: Event Filtering and Throttling
------------------------------------
Relevant document:
draft-niemi-sipping-event-throttle-reqs-01.txt
Slides presnted in:
pres-niemi-event-throttle-ietf-57.ppt
pres-niemi-sipping-ietf57-throttles-17072003.ppt
Discussion led by Aki Niemi
Changes:
1) Updated model. A throttle defines minimum time
period between two notifications
2) Updated use cases
3) Refined requirements
4) Aligned language with model
Open issues:
1) Should use cases be more elaborate?
Proposal: No
2) Are Requirements are solid enough?
Seem to be.
3) Is scope for work well defined?
Seem to be.
Discussions:
- It was suggested that it would be worth noting in
the draft about the type of buffering needed (like LIFO, FIFO etc)
Conclusion: Chairs will recommended to the ADs to adopt this
draft as WG item.
Topic: DPNSS to SIP Interworking
------------------------------------
Relevant document:
draft-mukundan-sipping-dpnss-02.txt
Slides presented in:
pres-mukundan-sipping-dpnss-ietf-57.ppt
Discussion led by Ranjith Mukundan
Difference between DPNSS MIME and QSIG/ISUP MIME
1) Similar to RFC 3204 (MIME for ISUP/QSIG
2) Mandates single binary coded octet message length
field
3) Specifies message buffering option
4) Mandates single DPNSS call per SIP dialog
Discussions:
- Henning indicated that this doesn’t work with the MIME model.
- Some were skeptical about the usefulness of doing this work.
- There was a feeling that the group did not have enough expertise to
take on this work.
- Gonzallo indicated that solving the MIME type is reasonable but the
translation work is a tough thing to do.
Conclusions: This will NOT be taken as WG item and it will proceed as
an individual contribution.
Topic: Discussion of End-to-Middle Security
---------------------------------------------
Relevant document:
draft-ono-sipping-end-middle-security-00.txt
Slides presented in:
pres-ono-end2middle-ietf-57.ppt
Discussion led by Kumiko Ono
Issues:
1) End-to-end encryption may conflict with some
features provided by intermediaries
2 )Use cases:
a. Logging services (IM logging,
other logging)
b. Hotspot service
c. Connecting to home SIP server
via partially trusted proxy
3) Session-policy
4) Transcoding
Proposed Mechanism:
• Allows a UA to disclose data to selected
intermediaries
• End-to-middle encryption uses S/MIME CMS Enveloped
data for intermediaries.
Discussions:
- People felt that this is a very interesting WI.
- Jonathan R said that we need to add more use cases
to explain the problem of addressing data for intermediaries by
user-agent.
Conclusions:
1) There was consensus in the room that work has
enough interest in the group.
2) There was consensus that the requirements on
end-to-middle & middle-to-end security should to be taken on as WG
item.
Topic: Phone-related Status and Presence
------------------------------------------
Relevant document:
draft-rosenberg-peterson-simple-pidf-phone
Slides presented in:
pres-rosenberg-sipping-day2-ietf-57.ppt
Discussion led by Jonathan Rosenberg
Discussions:
-Difference between human presence vs device presence.
- Rohan said that states like dialing/ringing etc are not applicable to
device or user; these are particular to a call/dialog. Some of the raw
data is useful, but presence may not be right place for it.
- Henning: Information like line-state etc are not too useful as
presence information.
Conclusions:
a) Hum on “Dealing with presence issues of phone” as useful work
indicated a consensus..
b) Jonathan proposed to develop more use cases for the draft.
c) Is this a SIMPLE or SIPPING activity? Chairs to discuss with SIMPLE
chairs.
Topic: Session Diagnostics in SIP
----------------------------------
Relevant document:
draft-johnston-sipping-rtcp-summary-00.txt
Slides presented in:
pres-johnston-sipping-rtcp-summary-ietf57.ppt
Discussion led by Alan Johnston
Summary:
1) Delivery of RTCP summary reports to third parties
a. Logging is main motivation
2) Three alternatives
a. Forking RTCP to multiple
locations
b. Carrying in SIP header in BYE
c. Event package (preferred)
Discussions:
1) Should RTCP be transferred to third parties?
2) What is the purpose of this? If this is for fault management or
performance management, this is not needed. SNMP management tools
should be sufficient.
3) How does this compare to RMON?
Conclusions: This will be deferred to this to the list. Alan is asked
to investigate RMON work and provide some comparison here.
ACTION ITEMS
-------------------
1) John Elwell volunteered to provide a list of ECMA contacts for QSIG
to
SIP work o Allison Mankin.
2) Chairs to discuss netconf and XCAP reconciliation proposals with ADs.
3) Francois Audet volunteered to review the qsig2sip document and
respons
on-list.
4) Francois Audet volunteered to send text relating to alternate
approaches such as ALG and MIDCOM for the ICE usage scenarios document.
5) Chairs to discuss moving some ICE work into MMUSIC and SIP with ADs.
6) Chairs to discuss
adding draft-rosenberg-sipping-app-interaction-framework-00 and
draft-burger-sipping-kpml-02 as WG items with ADs.
7) Chairs to work withs AD to add charter item(s) for end-to-middle and
middle-to-end security requirements.
8) SIPPING chairs to discuss phone-presence with SIMPLE chairs and ADs
to dtermine where thiswork belongs.
9) Alan Johnston was asked to consider how RMON work relates to
proposed RTCP summary work and report to the mailing list.