Subject: Re: [Sipping] Some comments on draft-camarillo-sipping-early-media-01.txt

From: Gonzalo Camarillo <[email-masked]>
Date: Thu, 03 Apr 2003 09:25:53 +0300

Alan,

inline

Alan Johnston wrote:
> At 08:30 PM 3/13/2003 +0000, Drage, Keith (Keith) wrote:
> 
> <snip>
> 
>> 10)     Section 3, 1st paragraph, not a comment that requires fixing, 
>> but we have a dependency to the Join draft which will need to be 
>> finished before or at the same time as this draft.
>>
>> 11)     Section 3, 1st paragraph, Amend final sentence to read "... by 
>> sending a new INVITE request to the URI it received in the Join header 
>> field."
> 
> 
> This entire section is quite confusing.  I think that Gonzalo does not 
> mean to reference the Join header field - it has no application in this 
> example.  I think he means to reference the To-Join header field 
> proposed by Jonathan in the original call package 
> (http://www.softarmor.com/sipping/drafts/morgue/draft-rosenberg-sip-call-package-00.txt). 
> 
> 
> Also, the reference 5 cited in this section is the Application 
> Interaction Framework which again has no bearing on this idea of 
> separate dialogs for regular and early media.  Perhaps the Application 
> Component Architecture document was the intended reference?
> 

The idea (which was originally proposed by Jon), is to make the UAS 
establish early media with the UAC in the same way as an application 
server in the path would do it. Therefore, the idea is to reference the 
work of the application interaction design team. That's why we reference 
the draft below:

http://www.ietf.org/internet-drafts/draft-rosenberg-sipping-app-interaction-framework-00.txt

Regarding the Join header, the draft above says:

However, the INVITE from the caller
    indicated that the device is capable of acting as a focus. How did it
    do that? It did so by indicating support for the SIP Join extension
    [11] which allows a UA to request to be conferenced into an existing
    dialog. As such, both app1 and app2, acting as a pure UAC, generate
    an INVITE towards this focus, with a Join header requesting to be
    added to a conference which includes the original dialog. The result
    is two additional dialogs, dialog A and dialog B respectively, which
    join the original dialog in their connection to a focus co-resident
    with the caller.

Reference [11] in that draft is:

[11] R. Mahy and D. Petrie, "The session initiation protocol (sip)
    join header," Internet Draft, Internet Engineering Task Force, Oct.
    2002.  Work in progress.

Once we resolve other issues related to early media, we intend to align 
this section with the application interactions work, but with this 
summary I believe it is clear what we are trying to do.

Thanks,

Gonzalo

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---

From: Alan Johnston <[email-masked]>
Date: Fri, 04 Apr 2003 13:39:56 -0600

Gonzalo,

Thanks for replying to my comments.

After I had sent my reply I had also found the use of Join in the app 
interaction framework and I meant to post comments about that draft as 
well.  I think the use of Join in that draft is also not a good idea.  I 
haven't come to a final conclusion yet, but I suspect that the Replaces 
primitive is much closer to a better fit than Join, especially in the app 
interaction where no media mixing is ever involved.  Turning every call 
placed into a conference call but without any media mixing seems very, very 
odd.

I will continue to think through these scenarios and post more on both 
drafts soon.

Also, I'm not sure it is a good idea to align the application interaction 
framework (which deals with stimulus signaling and markup delivery) with 
early media, as they are such different things.  I

Thanks,
Alan Johnston
WorldCom
sip:[email-masked]

At 11:25 AM 4/3/2003 +0300, Gonzalo Camarillo wrote:
>>>sending a new INVITE request to the URI it received in the Join header field."
>>
>>example.  I think he means to reference the To-Join header field proposed 
>>by Jonathan in the original call package 
>>Interaction Framework which again has no bearing on this idea of separate 
>>dialogs for regular and early media.  Perhaps the Application Component 
>>Architecture document was the intended reference?
>
>this section with the application interactions work, but with this summary 
>I believe it is clear what we are trying to do.
>
>Thanks,
>
>Gonzalo
>

---

From: Gonzalo Camarillo <[email-masked]>
Date: Sat, 05 Apr 2003 09:09:32 +0300

Alan,

> Also, I'm not sure it is a good idea to align the application 
> interaction framework (which deals with stimulus signaling and markup 
> delivery) with early media, as they are such different things.  I

I believe it is alright to align them, since early media can be 
bi-directional as well, and may involve interactions with the UAC. This 
way, if the UAS sends early media to the UAC in order to interact, it 
uses the same mechanism as if it sends media only to say "the user is 
being alterter".

Thanks for your comments,

Gonzalo