Subject: RE: [Iptel] Comments on 2806bis-08 (tel:uri)

From: "Bender, Andrew" <[email-masked]>
Date: Fri, 9 May 2003 23:46:04 -0400

> -----Original Message-----
> From: Henning Schulzrinne [mailto:[email-masked]]
> Sent: Friday, May 02, 2003 3:58 PM
> To: [email-masked]
> Cc: [email-masked]
> Subject: Re: [Iptel] Comments on 2806bis-08 (tel:uri)
> 
> Beyond the N11 numbers and the various *99=highway patrol numbers, 
> there are also vertical service codes 
> (http://www.nanpa.com/number_resource_info/vertical_service.html). 
> Examples include *66 and *72. These aren't really identifiers for 
> telephone subscribers, so my inclination would be to explicitly 
> declare them out of scope. I can see no useful application in the 
> context of a URN such as the tel: schema.

Thus you make handling of vertical service codes by events or in-band compulsory vs using the URI? Is this the intention? Is this unnecessarily limiting?

Regards,
Andrew Bender
taqua.com

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From: Henning Schulzrinne <[email-masked]>
Date: Sat, 10 May 2003 08:50:09 -0400

> Thus you make handling of vertical service codes by events or in-band
>  compulsory vs using the URI? Is this the intention? Is this 
> unnecessarily limiting?

I think there are four possibilities:

1) Declare *XX out of scope for now; we can add this later once we 
figure out a clean way to do this and there has been a demonstrated 
need. I think this can be justified if *XX can be consistently treated 
as identifying a logical endpoint and is a call endpoint. I don't use 
these rip-off codes much, but they seem to come in two flavors: one just 
does something (changes setting), but there is no call to anywhere. The 
other kind invokes some kind of IVR-based service that prompts for 
information or delivers information. *51 (Who Called Me?) may be an 
example.

2) Declare it out of scope since they don't fit the 2806 URN-like model 
of identifiers of telephone end system. Instead, KPML, 2833, SIP URIs or 
similar mechanisms should be used, just like any other in-band service 
invocation (aka DTMF). After all, once we start adding *XX, there is no 
logical reason not to add other DTMF service sequences, e.g., voice mail 
sequences. (For SIP URIs, there is no doubt as to who should do what and 
this fits pretty well with the model of special user-name parts of SIP 
URIs that invoke services.)

3) Ignore the conceptual problems and treat them as local numbers, with 
a context.

4) Define a new URI that explicitly deals with dial strings. I think 
such a URI is a bad idea (we don't have URIs that encode telnet 
sequences of characters, either), but others may consider this attractive.

My preference is (2), but I'd welcome feedback. I would prefer that this 
debate not delay progress indefinitely.

> 
> Regards, Andrew Bender taqua.com