Subject: Re: [Simple] Three dimensions of service

From: Adam Roach <[email-masked]>
Date: Mon, 07 Mar 2005 13:57:41 -0600

Brian Rosen wrote:

> Yep, I understand that you think this is possible. I don't. Try to 
> think of what it is that the icon would look like that would show you 
> the difference between, say, a PTT that was half duplex and another 
> that was full duplex. Is that what you want to see?

I believe the prospect of "full duplex PTT" is so painfully contrived as 
to be pretty much worthless as an example.

/a

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From: Paul Kyzivat <[email-masked]>
Date: Mon, 07 Mar 2005 15:31:28 -0500

I think there is no reason to render icons that display what the service 
"is". What is useful is to render icons that indicate how the watcher 
may *use* the service. That is determined by the understanding that the 
watcher device has understanding of the published info as well as having 
software that allows the user to do stuff with it.

So what is important is that the watcher be able to figure out enough to 
make that determination. If the watcher has something that can make use 
of a service that is half duplex voice with some particular described 
form of floor control, and if it wants to display that as a PTT icon, 
then fine. If the presence data doesn't sufficiently describe this - 
e.g. it doesn't say what kind of floor control is required - then it is 
broken.

	Paul

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From: "Brian Rosen" <[email-masked]>
Date: Mon, 7 Mar 2005 16:39:17 -0500

There is our disconnect.

You think you can invent enough variables to do that, and I think you can't.
Another way to look at that is that if you have more than a handful of
variables, no human can determine if two services are compatible, even if
you could figure out how to display the variation in an icon.  You are
talking about way more than a handful.

This is reverse engineering of service from capabilities, and we usually
think of such things as very hard.  You are guessing that half duplex +
floor control + audio is a PTT service.  Maybe yes, maybe no.  If you want
to declare that the only possible use for half duplex + floor control +
audio is a PTT service, then maybe.  I suspect we don't want to go there.

Brian

> -----Original Message-----
> From: Paul Kyzivat [mailto:[email-masked]]
> Sent: Monday, March 07, 2005 3:31 PM
> To: Adam Roach
> Cc: Brian Rosen; 'Simple WG'; 'Aki Niemi'; 'Henning Schulzrinne'
> Subject: Re: [Simple] Three dimensions of service
>