Re: [Sip] FW: I-D Action:draft-kaplan-sip-session-id-00.txt

[Hadriel Kaplan <HKaplan at acmepacket.com>]

> -----Original Message-----
> From: Ian Elz [mailto:ian.elz at ericsson.com]
> Sent: Wednesday, November 19, 2008 6:40 AM
>
> I don't think that having the first B2BUA synthesize the session-id
> would work. The idea is to have it end-to-end to solve the problem so
> having it put in by a B2BUA would not solve the problems.

Can you describe why having a B2BUA generate a Session-ID, if and only if one was not in the message already, would be worse than not generating one at all?

> While this draft proposes B2BUA
> actions the defined actions will only occur if the B2BUA fully
> implements this draft.

The draft doesn't say what a B2BUA should do if no header exists.  It does not say the B2BUA can not generate one in such a case.  I consciously left that as a possibility, knowing it would be a while before UAC's would generate one.


> The bigger issue is what is to stop a B2BUA either removing the
> session-id or generating one of its own.
> RFC 3261 defines a B2BUA as a concatenation of a UAS and a UAC. What
> happens between the UAS and UAC parts is undefined and there is no
> specification as to what actions the B2BUA should take when passing a
> request from the UAS to the UAC. There was a draft presented to the
> sipping wg to try an define actions of B2BUAs but this was rejected by a
> hum as dangerous. I guess that the consensus was that the B2BUA should
> remain totally undefined so that it could perform any action that was
> required. [Declaration of interest: I was a contributor to this now
> expired draft.]

I'll tackle those in a separate email.


> A couple of additional items which may need to be considered in the
> draft.
> Is it possible to include a list of headers which currently use the
> existing dialog identifiers? Others which you have not mentioned include
> Target-dialog, Join and In-reply-to.

Funny you mention it - I was tempted to go do it in the draft, but I thought it wasn't really the place to do it because the list could change, and there're a bunch of proprietary ones too, and the goal of the draft isn't to change them.  So I figured it was better to just give a couple examples.  But I can certainly do it if you think it would be useful.

> Is it proposed to propose modifications to the RFCs for the existing
> headers which use dialog ids to use the session-id?

Nope.  If someone wants to propose that in the future that's up to them, but I'm not suggesting that for this draft.  I *do* think some of the XML packages that include them should consider the Session-ID as an alternative (not a replacement - just an alternative).  But only for the ones in draft status or proprietary ones, not published RFCs.


> It is probably necessary to specify B2BUA actions in cases of 3PCC and
> what happens to the session-id in these cases.

Would it be any different?

Thanks for reviewing!

-hadriel
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