Re: [splices] Answering an A/V Call Using Two Separate Devices proposal

Simon Pietro Romano <spromano@unina.it> Wed, 25 May 2011 15:22 UTC

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Date: Wed, 25 May 2011 17:21:53 +0200
From: Simon Pietro Romano <spromano@unina.it>
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To: "Shekh-Yusef, Rifaat (Rifaat)" <rifatyu@avaya.com>
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Subject: Re: [splices] Answering an A/V Call Using Two Separate Devices proposal
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I *personally* agree with Rifaat. Let's first discuss the overall 
approach of the call flow and then decide on the best venue where to 
carry out such work.
This said, and based on the discussion we are having on the list, I bend 
towards considering INVOKE as a straightforward "mechanism" which I 
would be glad to see supported.

Simon


Il 25/05/2011 14:32, Shekh-Yusef, Rifaat (Rifaat) ha scritto:
>
> Hi Peter,
>
> >2) INVOKE is more mechanism than a new header. [A method is a bigger 
> deal than a header]
>
> Did you really think that I do not understand that defining a method 
> is a bigger deal than defining a header? J
>
> My comment was about the specifics of the call flow and has nothing to 
> do with defining a method or a header.
>
> Regards,
>
> Rifaat
>
> *From:*Peter Musgrave [mailto:musgravepj@gmail.com]
> *Sent:* Tuesday, May 24, 2011 8:42 AM
> *To:* Paul Kyzivat
> *Cc:* Shekh-Yusef, Rifaat (Rifaat); splices@ietf.org
> *Subject:* Re: [splices] Answering an A/V Call Using Two Separate 
> Devices proposal
>
> I agree with Paul that:
>
> 1) This works ok.
>
> 2) INVOKE is more mechanism than a new header. [A method is a bigger 
> deal than a header]
>
> I'd also observe in a "real politik" sense that the potential energy 
> barrier to geting a new SIP method in place will likely be 
> significant. I would expect it would have to be a dispatch-ed WG all 
> on it's own. People will decide to either use it to solve world hunger 
> - or decide that it is the root of all evil.
>
> Under "out there" ideas - would it be possible to put the Action 
> header in a PUBLISH? Would this allow the same signalling semantics as 
> INVOKE without the need for a new method?
>
> Peter Musgrave
>
> On Mon, May 23, 2011 at 9:07 AM, Paul Kyzivat <pkyzivat@cisco.com 
> <mailto:pkyzivat@cisco.com>> wrote:
>
>
>
> On 5/23/2011 8:56 AM, Shekh-Yusef, Rifaat (Rifaat) wrote:
>
> I do not see how this proposal is "less mechanism" than the original 
> proposal, but I tend to agree with you that this might be "a matter of 
> taste".
>
> The devil is in the details here, and we don't have enough details.
> So its all in the set of assumptions one is making.
>
> In the end we probably aren't going to standardize services - just 
> mechanisms for creating services. But perhaps we will have an 
> "examples" doc that shows how the mechanisms might be used to create a 
> range of interesting services such as these. If so, I would think we 
> would need to work through each one in detail, carefully defining all 
> the assumptions about the environment.
>
> And that is really what it takes to decide on each particular 
> "action", because those seem to be rather specialized. At the moment I 
> don't have a vision of a clear and obvious set of actions that enable 
> all the interesting services. Its more a matter of crafting an action 
> to support one or a few services. I wish it was more clear cut than 
> that. Maybe it will become so with more study.
>
>        Thanks,
>        Paul
>
>     Regards,
>      Rifaat
>
>
>
>     ________________________________________
>     From: Paul Kyzivat [pkyzivat@cisco.com <mailto:pkyzivat@cisco.com>]
>     Sent: Sunday, May 22, 2011 11:03 PM
>     To: Shekh-Yusef, Rifaat (Rifaat)
>     Cc: splices@ietf.org <mailto:splices@ietf.org>
>     Subject: Re: [splices] Answering an A/V Call Using Two Separate
>     Devices proposal
>
>     On 5/22/2011 8:49 PM, Shekh-Yusef, Rifaat (Rifaat) wrote:
>
>
>     You are then proposing the following:
>
>
>     Alice used her *phone* to answer the incoming call
>          |                     |                     |                
>         |
>          |                     | 200 OK [Audio]      |                
>         |
>          |                     |-------------------->|                
>         |
>          |                     |                     | 200 OK [Audio]
>          |
>          |                     |                    
>     |-------------------->|
>          | CANCEL              |                     |                
>         |
>          |<------------------------------------------|                
>         |
>          |                     |                     |                
>         |
>          |                    
>     |<---dialog1------------------------------->|
>          |                    
>     |<======audio==============================>|
>          |                     |                     |                
>         |
>          | INVITE Alert-Info and [Video]             |                
>         |
>          |<--------------------|                     |                
>         |
>
>     What happens here?
>     Will the user be required to take an action on the PC to accept
>     the INVITE?
>     Or you are expecting the PC to provide an answer without user
>     intervention?
>
>
>     Could  be handled various ways.
>
>     The alert-info could suggest auto-answer. (The PC *honoring* such a
>     request might be conditional on who it comes. But even if not honored
>     for auto-answer it might still alert *differently*.) If it wasn't
>     auto-answered, and returned 180, it could be followed up with an
>     INVOKE
>     to force the answer.
>
>             Thanks,
>             Paul
>
>          | 200 OK [Video]      |                     |                
>         |
>          |<--------------------|                     |                
>         |
>          |                     | re-INVITE [A/V]     |                
>         |
>          |                     |-------------------->|                
>         |
>          |                     |                     | re-INVITE [A/V]
>         |
>          |                     |                    
>     |-------------------->|
>          |                     |                     | 200 OK [A/V]  
>          |
>          |                     | 200 OK [A/V]      
>      |<--------------------|
>          |                     |<--------------------|                
>         |
>          | ACK                 |                     |                
>         |
>          |<--------------------|                     |                
>         |
>          |                     |                     |                
>         |
>        
>      |<------dialog2------>|<---dialog1------------------------------->|
>          |                     |                     |                
>         |
>          |                    
>     |<======audio==============================>|
>        
>      |<============================video==============================>|
>          |                     |                     |                
>         |
>
>     -----Original Message-----
>     From: Paul Kyzivat [mailto:pkyzivat@cisco.com
>     <mailto:pkyzivat@cisco.com>]
>     Sent: Sunday, May 22, 2011 5:09 PM
>     To: Shekh-Yusef, Rifaat (Rifaat)
>     Cc: splices@ietf.org <mailto:splices@ietf.org>
>     Subject: Re: [splices] Answering an A/V Call Using Two Separate
>     Devices
>     proposal
>
>
>
>     On 5/22/2011 2:40 PM, Shekh-Yusef, Rifaat (Rifaat) wrote:
>
>     Because a new INVITE will probably cause the PC to present the
>     user with a
>
>     UI component and wait for the users input.
>
>     Well, I suppose you would want the PC to indicate what is going on in
>     the UI in *some* way. But probably not exactly the same as getting
>     a new
>     call.
>
>     That could be handled via appropriate Alert-Info. To some extent
>     this is
>     a matter of taste. I am inclined to prefer an economy of
>     mechanism, and
>     I think the alert-info feels like less mechanism than the particular
>     INVOKE mechanism used in this scenario. (The invoke mechanism used
>     here
>     requires the phone to assume that the PC is aware of the dialog, and
>     able to associate it with the appropriate contact address for
>     doing the
>     invite.)
>
>            Thanks,
>            Paul
>
>     Regards,
>        Rifaat
>
>     -----Original Message-----
>     From: splices-bounces@ietf.org <mailto:splices-bounces@ietf.org>
>     [mailto:splices-bounces@ietf.org
>     <mailto:splices-bounces@ietf.org>] On Behalf
>
>     Of
>
>         Paul Kyzivat
>         Sent: Saturday, May 21, 2011 11:15 PM
>         To: splices@ietf.org <mailto:splices@ietf.org>
>         Subject: Re: [splices] Answering an A/V Call Using Two
>         Separate Devices
>         proposal
>
>         I guess all of that can work. But for the last part, if the
>         phone knows
>         enough to send the invoke to the pc, why can't it just send an
>         INVITE to
>         the pc?
>
>             Thanks,
>             Paul
>
>         On 5/21/2011 8:56 AM, Shekh-Yusef, Rifaat (Rifaat) wrote:
>
>         Hi,
>
>         We are still working on a new version of the INVOKE document
>         that removes
>
>         the implicit subscription.
>
>
>         Meanwhile I would like to continue the discussion of the
>         various possible
>
>         uses cases.
>
>         The following is a proposal for Answering an A/V Call Using
>         Two Separate
>
>         Devices.
>
>
>         Regards,
>             Rifaat
>
>
>
>               Alice                 Alice                Proxy        
>                  Bob
>                PC                 Desk Phone
>                |                     |                     |          
>                   |
>                |                     |                     |          
>                   |
>         Both Alice's devices subscribe to the reg event package, which
>         allows each
>
>         device to
>
>         discover the capabilities of the other device based on the
>         feature tags
>
>         provided by each device.
>
>         The Desk Phone knows that the PC supports Video, while the PC
>         knows that
>
>     the
>
>         Desk Phone only supports audio.
>
>                |                     |                     |          
>                   |
>                |                     | SUBSCRIBE reg       |          
>                   |
>                |                     |-------------------->|          
>                   |
>                |                     | 200 OK              |          
>                   |
>                |                     |<--------------------|          
>                   |
>                |                     |                     |          
>                   |
>                | SUBSCRIBE reg       |                     |          
>                   |
>                |------------------------------------------>|          
>                   |
>                | 200 OK              |                     |          
>                   |
>                |<------------------------------------------|          
>                   |
>                |                     |                     |          
>                   |
>                |                     |                     |          
>                   |
>         The two devices also subscribe to the dialog of each other.
>                |                     |                     |          
>                   |
>                |                     |                     |          
>                   |
>                | SUBSCRIBE dialog    |                     |          
>                   |
>                |-------------------->|                     |          
>                   |
>                | 200 OK              |                     |          
>                   |
>                |<--------------------|                     |          
>                   |
>                |                     |                     |          
>                   |
>                | SUBSCRIBE dialog    |                     |          
>                   |
>                |<--------------------|                     |          
>                   |
>                | 200 OK              |                     |          
>                   |
>                |-------------------->|                     |          
>                   |
>                |                     |                     |          
>                   |
>                |                     |                     |          
>                   |
>         The scenario starts with an A/V call from Bob to Alice
>                |                     |                     |          
>                   |
>                |                     |                     | INVITE
>         Alice [A/V]  |
>                |                     |                    
>         |<--------------------|
>                |                     | INVITE Alice [A/V]  |          
>                   |
>                |                     |<--------------------|          
>                   |
>                | INVITE Alice [A/V]  |                     |          
>                   |
>                |<------------------------------------------|          
>                   |
>                |                     |                     |          
>                   |
>
>
>         (*)
>
>
>         Let's assume that Alice used her PC to answer the incoming call
>         The PC instructs the phone to answer the audio call
>                |                     |                     |          
>                   |
>                | INVOKE Action:
>
>         urn:invoke:call:answer;media=audio;transducer=speaker|headset
>
>                |-------------------->|                     |          
>                   |
>                | 200 OK              |                     |          
>                   |
>                |<--------------------|                     |          
>                   |
>                |                     |                     |          
>                   |
>                |                     | 200 OK [Audio]      |          
>                   |
>                |                     |-------------------->|          
>                   |
>                |                     |                     | 200 OK
>         [Audio]      |
>                |                     |                    
>         |-------------------->|
>                | CANCEL              |                     |          
>                   |
>                |<------------------------------------------|          
>                   |
>                |                     |                     |          
>                   |
>                |                    
>         |<---dialog1------------------------------->|
>                |                     |                     |          
>                   |
>                |                    
>         |<======audio==============================>|
>                |                     |                     |          
>                   |
>                |                     |                     |          
>                   |
>         The PC then adds Video to the existing audio call.
>                |                     |                     |          
>                   |
>                | INVITE with Join [Video]                  |          
>                   |
>                |-------------------->|                     |          
>                   |
>                | 100                 |                     |          
>                   |
>                |<--------------------|                     |          
>                   |
>                |                     | re-INVITE [A/V]     |          
>                   |
>                |                     |-------------------->|          
>                   |
>                |                     |                     | re-INVITE
>         [A/V]     |
>                |                     |                    
>         |-------------------->|
>                |                     |                     | 200 OK
>         [A/V]        |
>                |                     | 200 OK [A/V]      
>          |<--------------------|
>                |                     |<--------------------|          
>                   |
>                | 200 OK [Video]      |                     |          
>                   |
>                |<--------------------|                     |          
>                   |
>                |                     |                     |          
>                   |
>              
>          |<------dialog2------>|<---dialog1------------------------------->|
>                |                     |                     |          
>                   |
>                |                    
>         |<======audio==============================>|
>              
>          |<============================video==============================>|
>                |                     |                     |          
>                   |
>                |                     |                     |          
>                   |
>
>
>
>         The scenario continues after the (*) above
>         Let's assume that Alice used her phone to answer the incoming
>         call.
>         The phone answers the audio call
>                |                     |                     |          
>                   |
>                |                     | 200 OK [Audio]      |          
>                   |
>                |                     |-------------------->|          
>                   |
>                |                     |                     | 200 OK
>         [Audio]      |
>                |                     |                    
>         |-------------------->|
>                | CANCEL              |                     |          
>                   |
>                |<------------------------------------------|          
>                   |
>                |                     |                     |          
>                   |
>                |                    
>         |<---dialog1------------------------------->|
>                |                     |                     |          
>                   |
>                |                    
>         |<======audio==============================>|
>                |                     |                     |          
>                   |
>                |                     |                     |          
>                   |
>         The phone then instructs the PC to initiate a video call to
>         join the
>
>         existing call
>
>                |                     |                     |          
>                   |
>                | INVOKE Action:
>         urn:invoke:call:join;media=video;dialog=dialog1
>                |<--------------------|                     |          
>                   |
>                | 200 OK              |                     |          
>                   |
>                |-------------------->|                     |          
>                   |
>                |                     |                     |          
>                   |
>         The PC then adds Video to the existing audio call.
>                |                     |                     |          
>                   |
>                | INVITE with Join [Video]                  |          
>                   |
>                |-------------------->|                     |          
>                   |
>                | 100                 |                     |          
>                   |
>                |<--------------------|                     |          
>                   |
>                |                     | re-INVITE [A/V]     |          
>                   |
>                |                     |-------------------->|          
>                   |
>                |                     |                     | re-INVITE
>         [A/V]     |
>                |                     |                    
>         |-------------------->|
>                |                     |                     | 200 OK
>         [A/V]        |
>                |                     | 200 OK [A/V]      
>          |<--------------------|
>                |                     |<--------------------|          
>                   |
>                | 200 OK [Video]      |                     |          
>                   |
>                |<--------------------|                     |          
>                   |
>                |                     |                     |          
>                   |
>              
>          |<------dialog2------>|<---dialog1------------------------------->|
>                |                     |                     |          
>                   |
>                |                    
>         |<======audio==============================>|
>              
>          |<============================video==============================>|
>                |                     |                     |          
>                   |
>
>
>
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-- 
                             _\\|//_
                             ( O-O )
    ~~~~~~~~~~~~~~~~~~~~~~o00~~(_)~~00o~~~~~~~~~~~~~~~~~~~~~~~~
                     Simon Pietro Romano
               Universita' di Napoli Federico II
                  Computer Science Department
         Phone: +39 081 7683823 -- Fax: +39 081 7684219
                 e-mail: spromano@unina.it
           http://www.comics.unina.it/simonpietro.romano

     <<Molti mi dicono che lo scoraggiamento รจ l'alibi degli
    idioti. Ci rifletto un istante; e mi scoraggio>>. Magritte.
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