Subject: [Ecrit] LoST #8: Dial strings

From: Henning Schulzrinne <[email-masked]>
Date: Thu, 13 Jul 2006 16:52:35 -0400

There are two issues:

(1) How to integrate this into the local dial plan.

(2) Whether LoST should support local (corporate) dial plans, such as

   9 (wait for dial tone) 911

In my opinion, since we have assumed that LoST services can be  
provided either by the access provider or the (SIP) service provider,  
having a LoST server provide the precise dial-out sequence is  
dangerous as only the SIP service provider determines the prefix  
part. Even on my office SIP phone at Columbia, I have two service  
providers: the local one and a commercial service provider that gives  
me better international rates...

Thus, I don't think it's a good idea to specify anything except the  
actual NANPA or equivalent digit strings. In other words, rosen- 
dialstrings is probably not helpful, at least not without very tight  
restrictions on the deployment model and with the potential for some  
unpleasant surprises.

As a separate item, more relevant to (say) the SIPPING config work,  
would be to provide a way to integrate emergency/service dial strings  
into the overall dial plan by defining a variable. In other words,  
the dial plan would have something like

9,$

where the $ is replaced by the UA-determined emergency digit string  
(I'm using comma for pause here). The local dialplan provider can  
then decide where this element resides in the dial plan and whether  
to specify something like

9,$T

In short, for the LoST document I propose that we use a simple digit  
sequence (plus *, #) only.

Henning

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From: "Brian Rosen" <[email-masked]>
Date: Thu, 13 Jul 2006 17:04:17 -0400

I have no problem with this resolution of the issue.

I think sip-config is the way to put "home" dialstrings into the phone.  We
should probably have the prefix separate and used for both home and
local/visited dialstrings.

Since I want to have a "manually configured" location possibility, also as a
sip-config thing, I'll volunteer to put a draft together on this.  The LoST
draft won't need to reference it; we'll do that in -phonebcp

Brian

-----Original Message-----
From: Henning Schulzrinne [mailto:[email-masked]] 
Sent: Thursday, July 13, 2006 4:53 PM
To: ECRIT
Subject: [Ecrit] LoST #8: Dial strings

There are two issues:

9,$

9,$T

Henning