Re: [splices] Answering a Call Using Two Separate Devices proposal

["Shekh-Yusef, Rifaat (Rifaat)" <[e-mail]>]

> -----Original Message-----
> From: [e-mail] [mailto:[e-mail]] On Behalf Of
> Paul Kyzivat
> Sent: Monday, April 25, 2011 8:44 AM
> To: [e-mail]
> Subject: Re: [splices] Answering a Call Using Two Separate Devices proposal
> 
> 
> On 4/25/2011 12:26 AM, [e-mail] wrote:
> >
> >
> > Then, during the adding video stream stage, Alice's desk phone send
> > INVITE(with video) to Alice's PC. I think Alice PC can accept the INVITE
> > request by Alice's manual action, while not by the refer-action indication.
> 
> Yes, that is certainly possible.
> What is tricky is what appears on the UI of the PC in this circumstance.
> Some possibilities:
> - appears as a "normal" (new) video call from Alice
> - appears as a "normal" (new) video call from Bob
> - appears as something special - a request for video support
>   from the desk phone.
> 
> To get this to be anything but the first of the above will require
> *something* we don't currently have.
> 

I think that we should try to achieve the second option of the 3 options you listed above.

How about if the PC subscribes to the Desk Phone dialog event package with include-session-description, combined with Peter's idea of slow start INVITE with Join from the PC, as follows:

    | SUBSCRIBE Event: dialog;include-session-description             |
    |-------------------->|                     |                     |
    | 200                 |                     |                     |
    |<--------------------|                     |                     |
    | NOTIFY [100 Trying] |                     |                     |
    |<--------------------|                     |                     |
    | OK                  |                     |                     |
    |-------------------->|                     |                     |

(*)
    |                     |                     |                     |
    |                     |                     |                     |
    |                     |                     |                     |
The following is a re-INVITE from the remote party (Bob) to add video 
to the existing audio call
    |                     |                     |                     |
    |                     |                     | INVITE Alice [A/V]  |
    |                     |                     |<--------------------|
    |                     | INVITE Alice [A/V]  |                     |
    |                     |<--------------------|                     |
    |                     | 100 Trying          |                     |
    |                     |-------------------->|                     |
    |                     |                     | 100 Trying          |
    |                     |                     |-------------------->|
    |                     |                     |                     |
    |                     |                     |                     |
The PC gets a notification of the new incoming call and the fact that it 
is video call.
    | NOTIFY dialog-info with session description                     |
    |<--------------------|                     |                     |
    | 200 OK              |                     |                     |
    |-------------------->|                     |                     |
    |                     |                     |                     |
The PC prompts the user and waits for his response. When the user 
accepts the request, the PC initiates a slow start INVITE to the Desk 
Phone as follows:
    |                     |                     |                     |
    | INVITE Join dialog1 |                     |                     |
    |-------------------->|                     |                     |
    | 200 [Video]         |                     |                     |
    |<--------------------|                     |                     |
    | ACK [Video]         |                     |                     |
    |-------------------->|                     |                     |
    |                     | 200 OK [A/V]        |                     |
    |                     |-------------------->|                     |
    |                     |                     | 200 OK [A/V]        |
    |                     |                     |-------------------->|
    |                     |                     |                     |


Regards,
 Rifaat