Subject: RE: [Ecrit] Dial Strings...

From: "Stastny Richard" <[email-masked]>
Date: Wed, 22 Mar 2006 18:30:10 +0100

I consider this very useful, and
not much additional effort
 
It requires also on location infromation based on country
It could be given back with the country default PSAP(s)
if only the country is known
 
I think this was also in the original cc.sos.arpa proposal from Brian
 
The basic question is what happens if the local dialstring is
clashing with other local numbers. THis may be left to the user
client, but we should give some guidance here.
 
Richard

________________________________

Von: Marc Linsner [mailto:[email-masked]]
Gesendet: Mi 22.03.2006 18:12
An: [email-masked]
Betreff: [Ecrit] Dial Strings...

I want to float an idea wrt dial strings.

We had some conversation for some time as to the value of the UA
understanding local emergency dial strings.  Since we're at the end of the
requirements for LoST, please express opinion on whether distributing local
dial strings via LoST is feasible and worthy of adding to our requirements
draft.

One example: UA boots --> UA launches LoST query and receives location
validation, PSAP uri (for fallback), and local dial strings.

Thanks,

-Marc-

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---

From: "Brian Rosen" <[email-masked]>
Date: Wed, 22 Mar 2006 12:32:11 -0500

The intersection of a local emergency dialstring with a home dialplan are
ugly.  We looked at this in PacketCable 2.0 work.  I believe the conclusion
is that with any of the methods people have for representing dialplans that
can be automatically processed by a phone or proxy, that inserting the local
dialstring into those dialplans is way too hard.  What you probably have to
do is to just have a list of local dialstrings and have the interpreter have
special processing that looks for them independently of the dial plan
interpretation.

The home dial string can be imbedded in the dial plan, and almost always is.

Brian

-----Original Message-----
From: Stastny Richard [mailto:[email-masked]] 
Sent: Wednesday, March 22, 2006 12:30 PM
To: Marc Linsner; [email-masked]
Subject: RE: [Ecrit] Dial Strings...

 

Richard

Thanks,

-Marc-

---

From: "Francois D. Menard" <[email-masked]>
Date: Wed, 22 Mar 2006 13:12:02 -0500

> The intersection of a local emergency dialstring with a home dialplan are
ugly.  

At home, I have a Mediatrix 2102
(http://www.mediatrix.com/products_devices.php?prodid=14) with 911 fallback
(US Patent 6,944,151) hooked to an Asterisk box and the digit map inside the
2102 recognizes 911 as a priority number sequence and falls backs on my POTS
line.  Asterisk has therefore no knowledge of 911 in its dial plan. This
works very well.  If the call is to go over VoIP instead of over POTS, then
the 2102 would send a SIP SOS and I would pray for the CMTS to knock off my
neighbors pumping P2P upstream so as to ensure I have priority over them
talking to the PSAP. Unfortunately, the CMTS providing service to my home,
even if my ISP interconnects directly to it, has no ability to do this as
part of the wholesale service provided by that cable company to my ISP. This
is why I keep a POTS line at home.  I asked the CRTC to force the ILECs to
sell 911-only POTS for $5 per month but the CRTC asked that I file a formal
complaint.

Cheers!

-=Francois=-

--
François D. Ménard
Chargé de projet
Xit télécom inc.
1350 rue Royale #800
Trois-Rivières, QC, G9A 4J4
Canada
[email-masked]
Tel: (819) 374-2556 ext. 268
Fax: (819) 374-0395
Cell: (819) 692-1383

-----Original Message-----
From: Brian Rosen [mailto:[email-masked]] 
Sent: 22 mars 2006 12:32
To: 'Stastny Richard'; 'Marc Linsner'; [email-masked]
Subject: RE: [Ecrit] Dial Strings...

Brian

-----Original Message-----
From: Stastny Richard [mailto:[email-masked]]
Sent: Wednesday, March 22, 2006 12:30 PM
To: Marc Linsner; [email-masked]
Subject: RE: [Ecrit] Dial Strings...

It requires also on location infromation based on country It could be given
back with the country default PSAP(s) if only the country is known

The basic question is what happens if the local dialstring is clashing with
other local numbers. THis may be left to the user client, but we should give
some guidance here.
 
Richard

Thanks,

-Marc-

---

From: Henning Schulzrinne <[email-masked]>
Date: Wed, 22 Mar 2006 14:36:35 -0500

We have gone over this issue a few times in the past. A short summary to 
prevent yet more of revisiting:

The issue of home vs. visited/local dial strings affects mostly mobile 
devices. This is not a major concern for desk phones in offices. Local 
(PBX-style) dial plans are not an issue for residential users. All 
mobile devices of interest use en bloc dialing ("Send" key), removing 
many of the dial plan collisions.

Thus, to make this problem tractable, can we state precisely the 
combination of circumstances where this is an issue? I see three scenarios:

- Enterprise: probably can configure emergency dial strings manually 
since this is a managed environment. I trust a sysadmin to spend enough 
time getting it right.

- Residential (DSL/cable): generally, not mobile, but may have overlap 
dialing. Doesn't have local dial extensions and such. Insertion into 
dial plan should be easy.

- Mobile (3G): no overlap dialing; mostly, no local dial plans 
(extensions). Needs both home and visited. Danger is mainly overlap with 
other service numbers.

Henning

---

From: Andrew Newton <[email-masked]>
Date: Wed, 22 Mar 2006 14:52:15 -0500

Henning,

I agree that we should break this down into scenarios to understand  
the requirements.  However, your residential case needs adjustment.   
There exist today VSPs who allow their customers to take their UAs  
out of their homes and plug them into other access networks, for  
instance at a relatives house or in a hotel.

-andy

On Mar 22, 2006, at 2:36 PM, Henning Schulzrinne wrote:

> We have gone over this issue a few times in the past. A short  
> summary to prevent yet more of revisiting:
>
> The issue of home vs. visited/local dial strings affects mostly  
> mobile devices. This is not a major concern for desk phones in  
> offices. Local (PBX-style) dial plans are not an issue for  
> residential users. All mobile devices of interest use en bloc  
> dialing ("Send" key), removing many of the dial plan collisions.
>
> - Enterprise: probably can configure emergency dial strings  
> manually since this is a managed environment. I trust a sysadmin to  
> spend enough time getting it right.
>
> - Residential (DSL/cable): generally, not mobile, but may have  
> overlap dialing. Doesn't have local dial extensions and such.  
> Insertion into dial plan should be easy.
>
> (extensions). Needs both home and visited. Danger is mainly overlap  
> with other service numbers.
>
> Henning
>
> Brian Rosen wrote:
>> From: Stastny Richard [mailto:[email-masked]] Sent:  
>> Wednesday, March 22, 2006 12:30 PM

---

From: Henning Schulzrinne <[email-masked]>
Date: Wed, 22 Mar 2006 15:05:28 -0500

Right. That was the "generally" part :-) Temporarily moving ATAs and 
phones out of the country is probably still going to be rare. (Other 
residential UAs, such as soft clients, are almost exclusively using 
en-bloc dialing, so they don't the same set of problems.)

Andrew Newton wrote:
> Henning,
> 
> I agree that we should break this down into scenarios to understand the 
> requirements.  However, your residential case needs adjustment.  There 
> exist today VSPs who allow their customers to take their UAs out of 
> their homes and plug them into other access networks, for instance at a 
> relatives house or in a hotel.
> 
> -andy
>

---

From: Henning Schulzrinne <[email-masked]>
Date: Wed, 22 Mar 2006 15:05:28 -0500

---

From: "Brian Rosen" <[email-masked]>
Date: Wed, 22 Mar 2006 15:15:42 -0500

Does that help?  If it's possible, everything has to support it.
If there are tradeoffs (efficiency for example), rarity can assist in
selection of alternative solutions.  I don't think we are there yet, we're
in requirements discussion.  The requirement is that we have to support
local dialstrings everywhere.

I do agree that an en-bloc dialing scheme makes it easier to support local
dialstrings.  Easier is not trivial.  En-Bloc dialing still has a dial plan,
with interpretation of that plan into what the device does to route the
call.  It doesn't affect ecrit work, it's only an aid in implementation of
these things inside the dialplan interpretation element (phone or first hop
proxy).

Brian