[itu-sg16] Instant Messaging in H.323 & Common Alerting Protocol (CAP)

[simao.campos at itu.int]

Paul,

using snippets from your reply: 

[begin snippet] 
> Opening a different can of worms: in the architecture, it is not clear 
> to me who is the gateway for the incoming CAP messages and be able to 
> perform some content translations. For example, beyond the XML to 
> ASN.1 conversion, to do a text-to-speech for audio-only H.323 
> terminals for delivery of the warning. Or, a distribution node near 
> the end delivery point can perform a de-referencing of an URI inside 
> the CAP message to an A/V content (e.g. for a digital TV distribution).

You're hinting toward what I assumed CAP would actually do: something entirely outside of H.323 itself.  I assumed there would be some kind of back-end CAP system that would take the contents and then create audio, video, and/or text, as necessary, and then instruct a special "warning"
device that would use H.323 to deliver the message in a human usable form.

Carrying CAP within H.323 certainly raises a lot of questions.  It's easy to do, but what does a terminal do with it?  PSTN gateway devices could not do anything with CAP, so we would still need the network-based warning system to deliver audio messages.  (Unless we out a TTS system in every GW, which I think is quite unlikely to happen.)  Terminals with display capability are the only devices that can reasonable accommodate reception of CAP messages directly.
[end snippet]

I wonder, would make sense to think of defining a new entity e.g. a "multimedia alert gateway", where we would state what the conversion requirements would be and then we go on to say how it would be handled within H.323? This maybe as an add on to H.323, or perhaps as something that could be used for H.32x (now putting Q1 in the discussion :-) ) and H.248 as well?

...

[begin snippet]

> Please do not see this as a discouragement to work on IM, I believe as 
> Paul that this is necessary for H.323's continuation as a

As a?  You're out of words?  ;-)

[end snippet]

That's what happens I swap between tasks... if I can remember what I wanted to say, something to the intent of maybe disconnecting the two issues and that work in IM for H.323 should go ahead as it is indeed strategic feature for H.323 from use case and user expectations perspective. Whether that could be a non-real time case of Annex G (as Gary hinted, if I understood it right), XMPP or something else, that remains to be discussed :-)

[trying to reply to the message in just one sit]

Thanks
Simão