Subject: RE: [Ecrit] Issue 30: Summary

From: "Michael Hammer \(mhammer\)" <[email-masked]>
Date: Tue, 31 Jan 2006 13:45:10 -0500

Brian,
 
I thought Barbara stated the problem well and a solution for
disambiguating the overlap in dial plans.  Note that plans is plural.
This is a question of conflicts in dial plans.
 
The core of this is that *** the endpoint doesn't know *** it is an
"emergency number" until the process for separating out the overlaps is
complete.  The delay or # or immediate is *how it knows*.
 
Your reasoning is circular here.  There is a Latin name for this, but
hey, I didn't study Latin.
 
Mike

________________________________

	From: [email-masked] [mailto:[email-masked]] On
Behalf Of Brian Rosen
	Sent: Tuesday, January 31, 2006 12:55 PM
	To: 'Stark, Barbara'; [email-masked]
	Subject: RE: [Ecrit] Issue 30: Summary

	If you would like, I'll raise this with the PSAP and NENA folks.
I don't think they will agree with you.

	The visited emergency number has to work immediately, which
means it has to be recognized by a dial plan, and not depend on timeouts
or # key presses.

	I think they would say that the home emergency number could have
the delay or #.

	You are proposing to change current behavior; as it stands now,
if you bring a phone into a country, it's the visited emergency number
that works.  I do understand that if you use an enterprise phone from a
VPN or something equivalent, everything breaks (you don't have the local
emergency number, you don't have correct location, and the call goes to
the home psap).   I think we really are better off with "both", even if
that causes some kinds of problems with home dial plans.  It's much
easier to deal with Extension 999 doesn't work as a 3 digit number when
I call from the UK as it does "please remember to hit # or wait 4
seconds" to get help when you are in the middle of London.

	Brian

________________________________

	From: [email-masked] [mailto:[email-masked]] On
Behalf Of Stark, Barbara
	Sent: Tuesday, January 31, 2006 10:44 AM
	To: [email-masked]
	Subject: Re: [Ecrit] Issue 30: Summary

	This seems generally reasonable to me, also. 
	However, there is an implicit expectation in the description
below that I'm not quite comfortable with, in the "precedence"
statement. That is, whether or not end of dialing string is
automatically recognized for visited emergency numbers.

	For devices that use a "Send" button, this isn't a problem.
"Send" must always be pressed to indicate "end of dialing". For these,
there would be no clash between a US "911" and UK "911xxx" dial string.
If the user enters "911xxx" + "Send", then this must never be
interpreted as "911". Similarly, "911" + "Send" is equally unambiguous
(in this example).

	SIP devices without a "Send" button generally employ a variety
of mechanisms to recognize "end of dialing". 
	 1. Some strings are automatically recognized; for example, when
a user dials any "N11" string and has an ATA configured for US dialing
plans, the ATA recognizes this string and automatically sends the SIP
Invite without waiting any further.

	 2. The user can usually press "#" to indicate end of dialing.
Many users are unaware of this fact. 
	 3. If the user does not press another digit in 4 or 5 seconds
(differs by device), this is interpreted as end of dialing, and the SIP
Invite is sent.

	What this means, is that, if a user enters a string that is not
automatically recognized as being "complete", and the user doesn't press
"#", there will be a 4 or 5 second delay between the time when the last
digit is pressed and SIP signaling begins.

	While I realize that this delay is generally undesirable, I
would prefer that there be no requirement to automatically recognize
"end of dialing" for visited emergency strings.

	The flip side of this is that if the ATA's current dialing plan
has an automatically escaped string that is shorter than the visited
emergency number (e.g., an ATA might automatically recognize "00" as a
complete string, and the visited emergency number is "000"), then the
ATA logic needs to stop recognizing "00" as a complete string. I'm fine
with this. The user can then dial "00" (+ timeout) or "00#", and also
"000" (+ timeout) or "000#".

	If done this way, the only clashes would be for exact matches. 
	Barbara 
	======================================== 
	On Jan 28, 2006, at 12:25 PM, Stastny Richard wrote: 

	1. By default, the device is set to use the home dialplan 
	and home emergency numbers, either directly or via 
	the home provider. 
	2. If not at home, the device get its location and also 
	the visited emergency numbers via some means 
	3. The visited emergency numbers take precendence 
	over the home dialling plan, if a clash occurs. 
	(Note: your home provider may provide you with an 
	escape code to override this, but then you definitely know 
	what you are doing - e.g. to reach 911xxx local numbers in UK 
	if you happen to be in the US.) 
	Note: this may cause some emergency calls done wrong, 
	but this is preferrable to missroute some real emergency calls 

	*****

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---

From: "Brian Rosen" <[email-masked]>
Date: Tue, 31 Jan 2006 14:04:02 -0500

You are trying to come at this by claiming that the engineering works a
particular way, so users should adapt.  I understand that the problem is
that you are putting a visited emergency number into a home dial plan.  That
is, in general, hard.

But I think the operative phrase is English: "get over it". The REQUIREMENT
is, I think, that the visited emergency number works, always, without
anything funny.  That's an end user experience requirement.  We have to
figure out how to make the devices meet that requirement.

So, if you had an overlap, it is the emergency number that "wins" (that is,
is recognized as the end of dialing), with some escape mechanism needed for
whatever it overlapped in the original dial plan.

Brian

  _____  

From: Michael Hammer (mhammer) [mailto:[email-masked]] 
Sent: Tuesday, January 31, 2006 1:45 PM
To: [email-masked]; Stark, Barbara; [email-masked]
Subject: RE: [Ecrit] Issue 30: Summary

Brian,

I thought Barbara stated the problem well and a solution for disambiguating
the overlap in dial plans.  Note that plans is plural.  This is a question
of conflicts in dial plans.

Your reasoning is circular here.  There is a Latin name for this, but hey, I
didn't study Latin.

Mike

  _____  

From: [email-masked] [mailto:[email-masked]] On Behalf Of
Brian Rosen
Sent: Tuesday, January 31, 2006 12:55 PM
To: 'Stark, Barbara'; [email-masked]
Subject: RE: [Ecrit] Issue 30: Summary

If you would like, I'll raise this with the PSAP and NENA folks.  I don't
think they will agree with you.

The visited emergency number has to work immediately, which means it has to
be recognized by a dial plan, and not depend on timeouts or # key presses.

I think they would say that the home emergency number could have the delay
or #.

You are proposing to change current behavior; as it stands now, if you bring
a phone into a country, it's the visited emergency number that works.  I do
understand that if you use an enterprise phone from a VPN or something
equivalent, everything breaks (you don't have the local emergency number,
you don't have correct location, and the call goes to the home psap).   I
think we really are better off with "both", even if that causes some kinds
of problems with home dial plans.  It's much easier to deal with Extension
999 doesn't work as a 3 digit number when I call from the UK as it does
"please remember to hit # or wait 4 seconds" to get help when you are in the
middle of London.

Brian

  _____  

From: [email-masked] [mailto:[email-masked]] On Behalf Of
Stark, Barbara
Sent: Tuesday, January 31, 2006 10:44 AM
To: [email-masked]
Subject: Re: [Ecrit] Issue 30: Summary

This seems generally reasonable to me, also. 
However, there is an implicit expectation in the description below that I'm
not quite comfortable with, in the "precedence" statement. That is, whether
or not end of dialing string is automatically recognized for visited
emergency numbers.

For devices that use a "Send" button, this isn't a problem. "Send" must
always be pressed to indicate "end of dialing". For these, there would be no
clash between a US "911" and UK "911xxx" dial string. If the user enters
"911xxx" + "Send", then this must never be interpreted as "911". Similarly,
"911" + "Send" is equally unambiguous (in this example).

SIP devices without a "Send" button generally employ a variety of mechanisms
to recognize "end of dialing". 
 1. Some strings are automatically recognized; for example, when a user
dials any "N11" string and has an ATA configured for US dialing plans, the
ATA recognizes this string and automatically sends the SIP Invite without
waiting any further.

 2. The user can usually press "#" to indicate end of dialing. Many users
are unaware of this fact. 
 3. If the user does not press another digit in 4 or 5 seconds (differs by
device), this is interpreted as end of dialing, and the SIP Invite is sent.

While I realize that this delay is generally undesirable, I would prefer
that there be no requirement to automatically recognize "end of dialing" for
visited emergency strings.

The flip side of this is that if the ATA's current dialing plan has an
automatically escaped string that is shorter than the visited emergency
number (e.g., an ATA might automatically recognize "00" as a complete
string, and the visited emergency number is "000"), then the ATA logic needs
to stop recognizing "00" as a complete string. I'm fine with this. The user
can then dial "00" (+ timeout) or "00#", and also "000" (+ timeout) or
"000#".

*****

The information transmitted is intended only for the person or entity to
which it is addressed and may contain confidential, proprietary, and/or
privileged material. Any review, retransmission, dissemination or other use
of, or taking of any action in reliance upon this information by persons or
entities other than the intended recipient is prohibited. If you received
this in error, please contact the sender and delete the material from all
computers. 117