Notes on SIP Session 2 at IETF 67
Reported by Chris Boulton
Agenda Bash - Chairs
Discussion on loose Route
- Dean - do we except this as a reasonable direction?
- Long line of discussion on grid etc property
- Rohan/Francois Audet concerned about backwards compatibility with new mechanism.
- Robert Sparks - likes current proposal.
- Cullen - do we want a milestone for this? Doesn't see backwards compatibility problem. Favor general solution.
- Jonathan R doesn't think there are any spec backward compatibility problems.
- Andrew Allen - No impact P-CSCF - it should work if compliant to specifications.
Concerns if SBC removes route header.
- CONCENSUS in the room that we have to do something in this space.
- No conclusion today BUT further work is required.
- Rohan proposes a design team to look at use-cases (for backwards compatibility).
- Jonathan - points out that adopting the draft DOES NOT mean that you are adopting the content - just the basis for work.
- Jonathan - No reference from GRUU and so wont hold it up.
- Rohan - disagrees
- Paul - clearly enhances GRUU and GRUU is definitely useable without it. Would not like to see GRUU held up.
- Scott Lawrence - Proposal has a lot of good properties regardless of GRUU.
- Andrew Allen - also doesn't want to see GRUU held up by this work. Do it as a parallel piece of work.
- Jonathan - clear that implementing GRUU does not require this - no normative dependency.
CHAIR DEAN - HUM - clear no need to link - Proposal of adopting as base-line - HUM of acceptance.
Location Conveyance - James Polk
- Outlined changes in -05 version
- James explains to Jon Peterson the motivation for the work.
- Paul K - what are the trust issues? James - entities can lie - Nothing in SIP to stop that.
- Rohan - questions when using location by value - do you need Geolocation.
- Jon Peterson - What is important - who are which entity inserted?
- James - just the type.
- Jon P - any value in adding inside a PIDF-LO object?
- CHAIR Keith - Are we heading in right direction by adding to a header - no one seems to have a problem with current direction.
- James Polk - runs through remaining OPEN ISSUES.
- Line discussion on the use of Content-Disposition - Miguel Garcia suggests using 'signal'. Take to the list to discuss.
- James Polk - location error created by this draft - needs additional
information and so James has written Geopriv draft for an error code
registry. Geopriv hate the idea.
Suggestion to split SIP/LOST etc and have separate registries.
- CHAIR - Keith - suggest conference call before Christmas to discuss.
- James Polk - walks through his 4 alternatives.
Connected Identity - John Elwell
- Current Status - WGLC - fixed except one issue - rejection of SIP by RFC 4474 verifier.
- John - proposal - NOT send 428 to a mid dialog request. Abandon
dialog if you get a 428/436/437/438 to a mid dialog request. John
outlines the pros and cons.
- Jon Peterson - I like it in general - has problems that maybe its too lax (around 427).
- Jonathan R - question to Jon Peterson - what are you worried about?
- Jon Peterson - worried about who is on the other side - there are cases when I care and cases when I don't.
- John Elwell - proposal - don't make statement about 428 and policy.
- CHAIR Keith - POLL - is the draft heading in the right
direction? Proposal seems to be maybe to add an information
header in a mid dialog request rather than rejecting out right.
- CHAIR - Keith - John Elwell to go and update doc.
Identity Coexistence - Jonathan R
- Problem statement - how mechanism work together (P-Asserted-ID and Identity).
- Long Line Discussion on inclusion of transient network in solution -
currently breaks and folks are concerned about a partial solution.
- Jonathan R - thinks you have to pick your poison - dont use cryptographically asserted messages.
- Paul K - why remove PAID when they trust each other?
- Jonathan R - wanted to keep PAID as intra domain.
- Cullen - Thinks that logic is wrong - rather than looking for PAID
and falling back to Identity - should be looking for Identity and
falling back to PAID.
- Jon Peterson make point that people are looking to allow 'man-in-the-middle' attacks to exsit in transient networks.
- CHAIR Keith/Jonathan R - Obvious interest in this work - Jonathan R
suggests another individual revision on the document. Talk to ADs
about scoping work.
- Jon Peterson - Agrees that work is valuable and is supported.
- Christer Holmberg - clarification of problem.
Outbound Discovery and High Availability - Jonathan R
- Problem statement.
- Jonathan R - draft is very complicated - needs to be split into 3 drafts
(see slides).
- Step through Discovery etc from the draft.
- Scott Lawrence - don't accommodate clients that don't use DNS.
- Jonathan R - agrees that its a side requirement.
- Scott Lawrence - Need some clarity on UA behavior. Doesn't
think you need additional mechanisms if you use single DNS SRV tree.
- BACK TO THE LIST
Handling large UDP responses in SIP - Scott Lawrence
- Problem Statement - responses get much bigger - causing fragmentation in UDP.
- GOAL is not to make UDP work with large responses - simply to flag in responses.
- Walk through of mechanisms (see slides).
- Draft recommends additional responses to flag that its going on.
- Unknown - concern raised that you can only send 100 provisional
response to Non-INVITE request - so what happens for things like
OPTIONS/UPDATE.
- Rohan - Non-Invite wants to deprecate provisional for Non-INVITE. He thinks this all is bad.
- Robert Sparks - has seen a lot of phones can deal with fragmented packets. Have you considered using SIP Redirection?
- Scott Lawrence - that has not been considered at this point.
- Cullen - things that do UDP should be able to re-assemble. Wanted to make sure those assertions are correct.
- Jonathan R - How do you 'Go and do TCP?'.
- Next Steps - WG interest? WG item?
- Scott Lawrence - more thought - take to the list.
XCAP Config - Dan Petrie
- Changes from -00 version.
- Problems identified in Montreal - how does it indicate it doesn't support XCAP. Dan runs through options (see slides).
- draft-petrie-sip-event-param-err-00 - Requirements presentation (see slides).
- Jonathan R - why did we want it as the same event package?
Can't remember motivation. Jonathan questions the lack of
interest in XCAP notifications.
- Mary - confirms that its an OMA dependency
- CHAIR - ACTION - DEAN to ask OMA about their dependency.
- Paul K - thinks that packetcable uses this draft - CONFIRMED.
Route Construction - Jonathan Rosenberg
- Problem statement (see slides) - confusing.
- UA/Registrar behavior not specified.
- Status - re-write to simplify - new backwards compatibility mechanism
+ very complex 3XX mechanism replaced by loose Route technique (loose
Route draft).
- Open Issues - requires input from IMS vendors.
- Rohan - doesn't like using Service-Route for providing the oubound proxy set.
- Christer Holmberg - very useful for IMS as well.
- CHAIRS Close meeting.