Subject: [dispatch] Preconditions and intermediaries

From: Gonzalo Camarillo <[email-masked]>
Date: Mon, 06 Jul 2009 16:56:49 +0300

Folks,

[as individual]

the following draft was presented in SIPPING in the the last IETF meeting.

http://tools.ietf.org/internet-drafts/draft-camarillo-sipping-precons-00.txt

This draft was a spin off from the "rollback" discussions that led to 
the following draft. It was a separate issue we decided to document in a 
separate draft.

http://www.ietf.org/internet-drafts/draft-camarillo-sipcore-reinvite-00.txt

Now, I would like to ask comments on the preconditions draft. If this is 
something people are interested in?

Cheers,

Gonzalo

---

From: Paul Kyzivat <[email-masked]>
Date: Mon, 06 Jul 2009 20:00:43 -0400

> 2.  Starting Using the Media Parameters Subject to Preconditions
...
>    However, the fact that the UAs can start using the new media
>    parameters does not mean that they need to start using them
>    immediately.  When preconditions are used, the UAS decides when to
>    start using them.  

Why do you say that?

For one thing offerer and answerer have more significance than UAC and 
UAS in any such decision.

For another, QoS needs to be obtained by both ends before it can be used 
by either end. The order in which it is obtained, and signaled that it 
has been obtained, is indeterminate.

When one end has been told that the other end has obtained it, and knows 
that it has obtained it, then it can start using it.

But that doesn't change the point about signaling the intent to start using.

	Thanks,
	Paul

---

From: Gonzalo Camarillo <[email-masked]>
Date: Thu, 23 Jul 2009 16:15:53 +0300

Hi Paul,

yes, you are right. The draft assumes a particular setting (e.g., the 
UAS is the answerer, the UAC reserves the resources and informs the UAS, 
and the UAS starts using the new parameters). I can fix that and add all 
the other possible scenarios for completeness.

However, before putting any more cycles on this, I would like to know 
whether or not people think this is important. If so, I can edit the 
draft so that we can progress it. On the other hand, if folks are not 
interested in this, I'd rather spend my cycles on something else.

Thanks,

Gonzalo