[Sip] draft minutes from SIP at IETF 67

[Dean Willis <[e-mail]>]

I'll try and get these posted shortly on the Proceedings and  
Softarmor sites.

Please review and respond with any corrections.


----------------------------

Draft Minutes for SIP at IETF 67
Edited by Dean Willis

Based on notes by David Bryan, Spencer Dawkins, Jason Fischl, Philip  
Mathews, Chris Boulton, Richard Barnes, and Others.


Session 1: Thursday 1300-1500 Grand Ballroom C

Topic: Agenda Bash and Status
Discussion led by Chairs
Slides included in proceedings.

Agenda accepted as presented

Working group members asked to more thoroughly review the certs draft  
and consent framework.



Topic: Outbound
led by Rohan Mahy
Read: draft-ietf-sip-outbound-05
Slides included in proceedings.

Changes since last version reviewed.

Issue: Which response code to use for failures. No objection noted to  
proposed use of 430 Flow Failed.

Issue: Noted that there is no mention of rport in the draft. Author  
will add text explaining that UA must put rport parameter in Via and  
send from port it's prepared to receive on, and add informative  
reference to NAT scenarios document.

Issue: Verify outbound support on first or all hops? Discussion  
seemed to resolve on checking at registrar and first hop. Author will  
make appropriate changes to the document.

Issue: How to resolve possible mismatch in max-flows parameter  
between visited proxy and home proxy? Discussion of this question was  
inconclusive, with a general consensus to defer further discussion.

Issue: Detecting instance-ID binding rules. This relates to concerns  
raised by 3GPP. A side meeting with 3GPP was held, and the author  
thinks he understands the problem and will propose a solution in the  
next revision of the document. The expected approach is to relax the  
flow-token language somewhat to allow the specific use case proposed  
by 3GPP.




Topic: Domain Certs
led by Vijay Gurbani
Slides included in proceedings.
Read: draft-gurbani-sip-domain-certs-03

The use of embedded DNS names to indicate the purpose of a  
certificate was quite controversial and much discussion ensued. The  
security community holds that extended certificates may be a better  
solution.

Discussion of the document touched on whether the work is required  
and how it relates to other work. The discussion was inconclusive,  
and we expect to resolve it via list discussion and possibly a  
subject-specific conference call.


Topic: Connection Reuse
led by Vijay Gurbani 	
Slides included in proceedings
Read: draft-ietf-sip-connect-reuse-07


Issue: Since the impact of this work has essentially declined to  
halving the number of TLS between proxies not separated by NATs,  
should we continue to pursue the work? The opinion of the room was  
weighted about 5 to 1 against continuing the work. The chairs are  
tasked to raise this question on the mailing list.

Issue: The approach taken by the outbound mid-dialg draft may obviate  
some of the applicability for this draft. Discussion on this point  
was inconclusive, and it will be taken as a topic for an upcoming  
conference call.

Issue: The CP behavior in this document contradicts that in draft- 
ietf-sip-outbound.



Topic: SIPS Guidelines
led by Francois Audet
Slides included in proceeedings
Read: draft-audet-sip-sips-guidelines-04

Changes in document since last version reviewed.

Issue: 4 point  BCP list proposed on-list by Dean Willis. Noted that  
Item 1 is somewhat out of place, as it simply restates RFC 3261.  
Suggested that a BCP should perhaps explicitly state this as a  
"reminder". The room seemed to agree with points 2 and 3. Point 4  
remained controversial, with a general consensus emerging that it  
should be expressed at a "Should" strength along with discussion of  
the risk model and consequences.



Topic: GRUU and Supporting Drafts 	
Led by Jonathan Rosenberg 	
Slides included in proceedings
Read: draft-ietf-sip-gruu-11,draft-rosenberg-sip-ua-loose-route-00

Change since last version reviewed.

Issue: GRUU subtype names. The room demonstrated a slight preference  
for the names used in -11 over known alternatives, but nobody seems  
particularly enamored with these names and the floor remains open to  
suggestions.

Discussion on ua-loose-route draft deferred to next session.


Session 2: Friday 0900-1130 Grand Ballroom C


Topic: UA-loose-route, continued from previous session.

Consensus noted that we do need some sort of solution for the general  
problem of delivery of URI parameters across contact-routing operations.

Issue: Concerns raised about backward compatibility. Noted that  
compliant P-CSCF should be OK.  Suggested that we have a design team  
revisit call-flows and analyze for backward compatibility issues.

Issue: Does GRUU normatively depend on this work? Resolved: GRUU does  
not reference this document. However, some participants feel it  
should, as the benefit of GRUU cannot be fully recognized in the  
absence of this specification.  The chairs asked for a hum, and the  
consensus of the room is that GRUU and ua-loose-route can proceed  
independently.

Question: Adopt this draft as baseline text for a WG effort, should  
the ADs approve the milestone? Consensus to adopt noted by chairs. To- 
do: Chairs to work with AD to set new milestone.

Topic: Location Conveyance
led by  James Polk and Brian Rosen
Slides included in proceedings
Read:  draft-ietf-sip-location-conveyance-05

Changes since last version reviewed.

The room discussed trust issues, location-by-value (needs  
geolocation), and the question of whether it is important to know  
which entity inserted a location. No changes to the document were  
noted as being required during this discussion.

The chairs polled for acceptability of current direction -- adding to  
a header. There were no objections noted to this direction.

Issue: Where to track the location error created by this draft?  
Proposed that we have separate registries for SIP and LOST.

Further discussion deferred to list and future conference call. To- 
do: Chairs to establish a conference call for discussion.


Topic: Connected Identity
led by John Elwell
Slides included in proceedings
Read: draft-ietf-sip-connected-identity-02

Current status reported as all issues fixed exception for rejection  
by RFC 4474 verifier.

Discussion concluded with a proposal to not make a statement about  
428 responses and policy, perhaps add an informational header into a  
mid-dialog request rather than rejecting outright.

Author will work with this approach and revise doc appropriately.


Topic: Identity Coexistence
led by Jonathan Rosenberg
slides included in proceedings
Read: draft-rosenberg-sip-identity-coexistence-00

Issue: How to deal with transit networks? This produced an extensive  
discussion. Proposed that logic in draft is inverted, and that we  
should perhaps be looking for Identity and falling back to PAID.

There seems to be some consensus that this work is valuable, although  
there is no consensus yet on the documented approach.

The author will revise the document for further discussion.


Topic: Outbound Discovery and Mid-Dialog Requests
led by: Jonathan Rosenberg
Slides included in proceedings
Read: draft-rosenberg-sip-outbound-discovery-mid-dialog-00

Issue: How to discover in the absence of DNS? There appears to be no  
consensus on whether this is a requirement.

Further discussion deferred to list.



Topic: Diagnostic Responses
led by Scott Lawrence
Slides included in proceedings
Read: draft-ietf-sip-hop-limit-diagnostics-03, draft-gurbani-sip- 
large-udp-response-00

Noted that ongoing NIT work proposes to deprecate provisional  
responses for non-INVITE transaction.

Proposed that SIP Redirection could be used to eliminate problem.

Author will bring discussion questions to the mailing list.


Topic: UA Profile Delivery
led by Dan Petrie
Slides included in proceedings
Read:  draft-ietf-sip-xcap-config-00 draft-petrie-sip-event-param-err-00

Changes since last version reviewed.

Noted that OMA has a dependency on XCAP change notifications. To:do;  
OMA liaison manager to open a dialog on this dependency.

Noted that PacketCable 2.0 uses this draft.



Topic: Route Constuction
Led by Jonathan Rosenberg
Slides included in proceedings
Read: draft-rosenberg-sip-route-construct-02

Noted that input from IMS vendors is needed to evaluate impact of  
this proposal. One speaker with some background in IMS opined that  
this technique should be useful with IMS.

Issue: Is Service-Route a reasonable way to provide the outbound  
proxy set? One speaker didn't think so, but no alternative  
suggestions were noted.

Further discussion deferred to mailing list.

Meeting adjourned several minutes past scheduled end of session.





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