Subject: RE: [MEDIACTRL] MS capabilities

From: "Chris Boulton" <[email-masked]>
Date: Wed, 28 Mar 2007 09:14:03 +0100

3/
Another point to note (and still under some discussion) is how a
media session can be identified by the control 'commands' sent via
one of the control channels, which 'manipulate' a given media stream
(eg play announcement). One thought is that a unique SIP dialog 
identifier (identifying one of the *y* SIP dialogs) should be
directly used in the commands sent over the control channel. 
This works fine when AS and MS are co-located, and as we had 
discussed in our first WG meeting, this may not always be case 
when a B2BUA is in between the AS and the MS. We will need to
sort through this issue some more.

[Chris Boulton] I think this is an important scope issue to address (Mr
B - your thoughts?).  In my opinion, to make such assertions (e.g.
insertion of a B2BUA between the AS and MS) is not in the scope of the
requirements OR core protocol design.  You are correct that a B2BUA will
break the current mechanism BUT then B2BUA functionality IS NOT defined
anywhere and so whatever tricks you adopt to traverse this could
adversely fail (man I have seen some weird stuff out in the wild).  For
this reason the base should be kept as pure as possible.  IF we (as the
group) feel there is a requirement (I have already discussed this with a
number of folks) for the Control Framework to have some sort of Relay
extension (not core - as MSRP has done) then so be it.  This would allow
a Control Framework compliant box to be able to traverse and
appropriately manipulate the underlying PDU's as it would RELAY the
control channel.  I am against 'shoe-horning' logic into the core
solution which will not guarantee success due to a vast and wide variety
of B2BUA behavior.

Thanks.

Chris.

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From: "Even, Roni" <[email-masked]>
Date: Thu, 29 Mar 2007 16:27:31 +0200

Hi,

I think that we can look at RFC 4575 that has the same problem of
correlating the users and SDP media to the event notification.

The user is identified by authenticated ID while media are identified
using the 'label' attribute specified also in the SDP. The AS can add
the label to the SDP going to the MS.

Roni 

> -----Original Message-----

> From: Chris Boulton [mailto:[email-masked]]

> Sent: Wednesday, March 28, 2007 10:14 AM

> To: Adnan Saleem; Diego B; Eric Burger

> Cc: [email-masked]

> Subject: RE: [MEDIACTRL] MS capabilities

> Information contained in this e-mail and any attachments are intended
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> Ubiquity Software Corporation. All unauthorized use, disclosure or

> distribution is strictly prohibited.  If you are not the addressee,
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5EA,

> Wales, United Kingdom.