It's not POST call-setup. It's AT call setup.
It's the difference between:
Line seisure by pressing key
*
User press Line appearance. This is reported to Presence/Dialog server.
PUBLISH or BFCP.
*
Presence/dialog for that line goes "busy" right away, for anybody that
sees it
*
Nobody can use that line regardless of how long it takes the user to
dial
Line seisure at call setup
*
User press Line appearance. This is local: no reporting anywhere.
*
Nothing changes anywhere
*
Line is "seized" when the call is actually made
*
In the interim between pressing the key, somebody else could also press
the key and make a call. If he's faster, he'll be able to seize the line before
the first guy.
Besides the mind-numbing complexity of doing the first approach, there are also
advantages to the second approach. It avoids the problem of having somebody
"hogging" the line by pressing on the key and not dialling anybody.
And frankly, the SIP mechanism to "arbitrate" the
line-seisure-by-pressing-an-appearance will by definition be very complicated
and generate lots of traffic. I don't be believe it will be simpler than BFCP.
Furthermore, there will be lots of potential for race condidtions (while the
NOTIFYs and PUBLISH are flying all over the place). This will result in very
poor user experience. Basically, pressing on the button will often "not work".
(I have a vision of pissed-off users repeatedly pressing the key that doesn't
want to turn on, and banging on their sets).
The second option, with line seisure at call setup does not suffer from this
problem. The expectation is that the line is "taken" when you actually make the
call, not when you press the button.
I will point out that PBXs (as opposed to key systems) often work the second
way, not the first way.
This is all very similar to arbitrating between making an outgoing call and
receiving an incoming one while dialing.
________________________________
From: Bill Mitchell [mailto:[EMAIL PROTECTED]
Sent: Friday, March 21, 2008 11:58
To: DOLLY, MARTIN C, ATTLABS
Cc: [email protected]; Audet, Francois (SC100:3055); [EMAIL PROTECTED]
Subject: RE: [BLISS] MLA with Floor Control
My answer is YES. Line seizing before call setup is worthwhile,
because it enables shout control with a **reasonable end-user experience**.
Line seizing post-call-setup is NOT worthwhile. It only adds confusion
with potential mid or post-dial line key hopping.
Pre-call-setup line seizure can be optional.
BFCP has the right primitives, but I firmly agree with Venkatesh that
it adds significant network complexity and would be a large barrier for
implementation. I'll add my vote for a SIP-based mechanism to communicate line
seize requests and responses.
-Bill
________________________________
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of DOLLY,
MARTIN C, ATTLABS
Sent: Friday, March 21, 2008 9:09 AM
To: Francois Audet; Venkatesh; Paul Kyzivat
Cc: Rohan Mahy; [email protected]
Subject: Re: [BLISS] MLA with Floor Control
I agree, NO
________________________________
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Francois
Audet
Sent: Friday, March 21, 2008 11:45 AM
To: Venkatesh; Paul Kyzivat
Cc: Rohan Mahy; [email protected]
Subject: Re: [BLISS] MLA with Floor Control
The real question is "should we do line seizing before call setup" as a
worthwile feature.
I think "No".
If the group feels "Yes", then we could look at BFCP. I really think we
should not be stupid enough to make this mandatory.
________________________________
From: Venkatesh [mailto:[EMAIL PROTECTED]
Sent: Thursday, March 20, 2008 21:49
To: Paul Kyzivat
Cc: Audet, Francois (SC100:3055); Rohan Mahy; [email protected]
Subject: Re: [BLISS] MLA with Floor Control
I don't disagree with your argument. However, I also think,
should a particular approach unduly complicate implementation of a feature
(especially require support from multiple network elements for a feature to
work), vendors are going to resort to non standard ways to implement the
feature as well......
Venkatesh
On Thu, Mar 20, 2008 at 9:15 PM, Paul Kyzivat <[EMAIL
PROTECTED]> wrote:
I'm not promoting one way or the other. Ultimately people
building
products will build the functionality they think they need to
sell their
products. If people feel this is important then they will want
a way to
do it. If it isn't standard then it will be nonstandard.
Paul
Francois Audet wrote:
>
>
>> There is a tradeoff...
>>
>> If multiple extensions can place outgoing calls from the same
>> line, then the line doesn't have "binary" status, so it can't
>> be indicated as active or not with a light. And you can't
>> "conference in" by picking up on the same line.
>>
>> While I am not into it myself, I can see how someone can
>> build a "business process" around the specific way in which
>> lines are managed by the phones, and then be very upset if
>> they can't get that same user experience.
>
> Yeah, sure, it's doable. I do not believe that adding the
concept
> of a Line number to do this is required to do this, or even
> desireable.
>
>> Now you can come up with some very nice UIs that provide
>> better user experience, if you have a suitable display
>> instead of just a bunch of lights. (E.g. an entry for the
>> "number" (AOR that people call), and a variable length drop
>> down list of active calls, showing the callerid of the
>> caller, how long it has been active, and which extensions are
>> currently connected to it.) But that is *different*, and
>> requires a device with richer UI.
>
> Agreed.
>
> My point is that we shouldn't bastardize the protocol with
all this
> complex extra protocol (Line numbers, BFCP,
NOTIFY/PUBLISH-storms, etc.)
> just do do this.
>
> The basic "single-lamp" based approach is doable without any
of this.
>
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