Subject: RE: [Sipping] SIP URL's with telephony numbers

From: "Michael O'Doherty" <[email-masked]>
Date: Mon, 12 Nov 2001 18:36:23 -0000

Sean, Jonathan,

The spec Bis05 says that recipients can interpret the SIP URL as a telephone
number even if the 'user=phone' is not present.

What I was looking for was some way for a sender to ensure, for whatever
reason, that a particular SIP URL (which may look very like a telephone
number) is definitely not interpreted by the recipient as a telephone
number. 'IP' rather than 'SIP' is not a problem  - I missed that in the BNF
(and didn't see it mentioned any place in the text ?).

If we are saying something like:

 - with user=phone it must be interpreted as addressing a traditional E.164
telephone number
 - with user=ip it must be interpreted as addressing a SIP CLIENT
 - with nothing the recipient may decide

this would be fine.

Cheers,

Mick.

-----Original Message-----
From: Michael O'Doherty [mailto:[email-masked]]
Sent: Monday, November 12, 2001 12:25 PM
To: [email-masked]'
Subject: [Sipping] SIP URL's with telephony numbers

>
>Hi, 
>A question about the use of SIP URL's with the username in the form of a
tel URL: 
>If we want the SIP address to be treated as a SIP address rather than as a
telephone 
>number (e.g. we might want to reach the SIP address associated with a
particular PSTN 
>number) two approaches come to mind that clearly avoid any confusion with a
SIP URL which 
>is intended to be routed to the PSTN:
> (a)    SIP:[email-masked];user=SIP 
> (b)    SIP:[email-masked]; 
>The first option (a) is effectively saying "even though the left part of
the SIP URL looks 
>like a telephone number I want it to be treated as a SIP address".  While
it can be argued 
>that this is the default anyway, it makes it explicit if we can use the
user field like 
>this.
>The second option achieves the same thing but arguably not as cleanly. 
>Any opinions on which is the better approach ? 

This is a non-problem. The user parameter exists already to disambiguate. If
its a phone number, its user=phone. Otherwise, its user=ip.

-Jonathan R.
---
Jonathan D. Rosenberg, Ph.D.                72 Eagle Rock Ave.
Chief Scientist                             First Floor
dynamicsoft                                 East Hanover, NJ 07936
[email-masked]                     FAX:   (973) 952-5050
http://www.jdrosen.net                      PHONE: (973) 952-5000
http://www.dynamicsoft.com

---

From: Ben Campbell <[email-masked]>
Date: Wed, 21 Nov 2001 15:44:49 -0600

Sorry for the late entry to the discussion. Comments inline.

Michael O'Doherty wrote:

> Sean, Jonathan,
> 
> The spec Bis05 says that recipients can interpret the SIP URL as a 
> telephone number even if the 'user=phone' is not present.
> 
> number. 'IP' rather than 'SIP' is not a problem  - I missed that in the 
> BNF (and didn't see it mentioned any place in the text ?).

And in the case of a sip: url, why should the caller have the ability to 
do that? Shouldn't the interpretation of the user part of the URL be 
entirely up to the domain specificied in the domain part? Why should the 
caller have any control over the interpretation of that name-space?

>  - with user=phone it must be interpreted as addressing a traditional 
> E.164 telephone number

I think that for a SIP URL, it should always be up to the designated 
domain to decide.

> http://www.dynamicsoft.com

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