RE: [Simple] Change to prescaps XML schema

[Markus.Isomaki at nokia.com]

Hi, 

See at the bottom.

> -----Original Message-----
> From: simple-bounces at ietf.org 
> [mailto:simple-bounces at ietf.org]On Behalf
> Of ext mikko.lonnfors at nokia.com
> Sent: 13 October, 2004 14:42
> To: dag.ekengren at hotsip.com; simple at ietf.org
> Subject: RE: [Simple] Change to prescaps XML schema
> 
> 
> Hi,
> 
> inline
> 
> > Hi,
> > 
> > I have a small suggestion, which actually has nothing to do with the
> > splitting of prescaps attributes.
> > 
> > I would like to be able to express that (for a service) 
> audio is full
> > duplex and video is half duplex.
> > 
> > Let me give an example:
> > * A PC has a softphone with audio and video capabilites
> > * The user has not yet plugged in a camera
> > 
> > The softphone will be able to send and receive audio but 
> only receive
> > video. If I understand the prescaps draft correctly, this is not
> > possible to express. Either the whole service is full duplex or half
> > duplex.
> 

In this case video is not even half duplex but simplex into one direction. The question is whether we can ever get to this kind of detail within presence. On this list I have seen people saying that details such as supported codecs etc. are outside the scope of presence and will be negotiated with SDP once the session establishment is in progress. You can similarly find out the limitation you explain below through SDP.

But the main point I wanted to say was that instead of half-duplex the correct way would be defining something like "receive-only". 

> Yes, that is correct. Basically this 'limitation' comes from 
> caller preferences because prescaps draft tries be very close 
> to the model presented in caller preferences. This is why you 
> can now only specify duplex for a whole contact. However, in 
> presence it actually might make sense to be able to specify 
> different duplex modes for different medias in a single tuple. 
> Other way to solve this could be to split the service into 
> multiple tuples which map into single device (softphone). One 
> tuple would have full duplex audio and other one half duplex video.  
> 

That's not right either, since the service capability is really the combination of those two medias, and there are no two separate services, as that kind of tuple splitting would suggest.

> - Mikko
> 

Markus

> > Thanks,
> > Dag
> > 
> > >-----Original Message-----
> > >From: mikko.lonnfors at nokia.com [mailto:mikko.lonnfors at nokia.com]
> > >Sent: den 13 oktober 2004 12:23
> > >To: simple at ietf.org
> > >Subject: [Simple] Change to prescaps XML schema
> > >
> > >Hi,
> > >
> > >Here is a proposal to change current XML schema defined 
> for prescaps.
> > >Intention is to align this work with the latest presence 
> data model.
> > >At a moment all prescaps attributes are defined in a single schema.
> > >Proposal is to spilt XML schema  into tree parts: person, 
> > service, and
> > >device. Below is the list how I think prescaps elements should be
> > divided.
> > >This is my first iteration on this so please check the list 
> > and comment
> > if
> > >you notice something strange.
> > >
> > >Device schema:
> > ><mobility>
> > ><description>
> > ><priority>
> > >
> > >Person schema:
> > ><description>
> > ><languages>
> > >
> > >Service schema:
> > ><audio>
> > ><video>
> > ><application>
> > ><control>
> > ><text>
> > ><type>
> > ><automata>
> > ><class>
> > ><duplex>
> > ><description>
> > ><event-packages>
> > ><priority>
> > ><methods>
> > ><extensions>
> > ><schemas>
> > ><actor>
> > ><is-focus>
> > ><languages>
> > >
> > >- Mikko
> > >
> > >_______________________________________________
> > >Simple mailing list
> > >Simple at ietf.org
> > >https://www1.ietf.org/mailman/listinfo/simple
> > 
> 
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