Re: [Ecrit] FW: FW: I-D Action:draft-rosen-ecrit-premature-disconnect-rqmts-02.txt

[Ted Hardie <hardie at qualcomm.com>]

At 10:30 AM -0800 1/13/09, Brian Rosen wrote:
>I'm trying to solve a problem where the user is doing the wrong thing.  By
>definition, his opinion is that he should terminate the call. 

And you are substituting the PSAP call taker's judgement for
the individual user's because it is statistically better.  But,
as the "intruder" case discussed below makes clear, there are
times when you already acknowledge that the user's judgement
is better.

>"Negotiating"
>with the user is not possible.  We can do something and provide an override,
>but it doesn't work to negotiate with the user.
>
>I do understand the "intruder" problem. 

I'm glad that we have at least this common ground.


>I'd like to be able to solve that
>in the best possible way.  If the user really knew what was happening, they
>would pull the battery out of the device, because any phone can be called
>any time. 

Note that in the "abuser" version of this, it really makes a difference as
to who calls (and the abused may be hurt for failing to respond to the
abuser's call as well as abused for reaching out for help).

>That's not a reasonable response, and I understand that.  We have
>a balance to strike.  Of course the override could and probably should be
>proactive (that is, if you should be able to invoke the override before you
>terminate).

Do you see it as reasonable to invoke the over-ride before the
call starts?  That is, start the call in a state so that the PSAP knows
it would not get the right to control the ending?

I would be more comfortable with this capability, as it also addresses
the other concern--use/abuse of this facility by non-PSAP uses.  If users
can start a call in way that prevents this facility being used, users can
choose to operate in this manner in contexts where they fear abuse
of the facility.

> That is also not a complete answer.  It seems to me that the
>incidence of bad judgment causing serious problems is so much more common
>than the intruder's shouldn't hear alerting that we ought to compromise in a
>way that facilitates the former rather than the latter.  Although I'm not
>entirely comfortable taking that position, I'm a heck of a lot more
>comfortable with that then any other proposed solution.

I would guess that you're not comfortable with it for the same reason
I am not.  It's hard to face someone whose situation got worse with
the reasoning "well, statistically things got better".

>I'm not at all worried about the "least surprise" issue with people coming
>in from other jurisdictions.  Surprise is the most common reaction to people
>in the jurisdictions it's been implemented in, mostly because you don't make
>emergency calls very often.  Most Canadians don't know that the PSAP can
>control termination on wireline calls.

This sounds like a great way to further fluster folks who are already
apparently too nervous to do the right thing.

>The current proposed mechanism is that you negotiate the feature with a full
>3 way handshake.

So UA can simply fail to support the feature during this handshake as
a form of negotiation?

> Then, normally, instead of termination, you signal
>hookstate.  If you get stuck (the signaling of hookstate doesn't complete,
>or the override is triggered), you terminate.  The PSAP has a way to alert.
>All that is required to make this work in complex networks is that the
>negotiation mechanism and the hookstate signaling mechanism is transparent
>to networks and devices other than the UAS and the UAC.  If either end
>really does send BYE, the call terminates. 

I guess I don't understand how the UA sends BYE here (and thus how this
remains "either end really does send BYE).
				regards,
					Ted Hardie



>Brian


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