Subject: [martini] Use of user=phone in gin draft

From: "Elwell, John" <[email-masked]>
Date: Thu, 18 Mar 2010 15:15:37 +0100

The examples in the gin draft include 'user=phone' in the contact URI registered with the SSP, e.g.: <sip:198.51.100.3:5060;user=phone;bnc>

I just wonder whether user=phone is appropriate here. The parameter makes a statement that the user part is a telephone subscriber number, which in this case, in the absence of a user part, is clearly not the case. However, when expanded and used in an inbound request (e.g., <sip:[email-masked]:5060;user=phone>, it can be correct. In fact, because the draft is limited to fully-qualified E.164 numbers in the user part, the presence of user=phone will always be correct.

So we would seem to have several choices:
1. Keep as is.
2. Omit from the REGISTER request but require the registrar to add it when constructing the complete contact URI.
3. Don't use user=phone at all.

I don't have a strong opinion - just raising the question.

John

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From: "Kevin P. Fleming" <[email-masked]>
Date: Thu, 18 Mar 2010 09:56:03 -0500

> 3. Don't use user=phone at all.

I don't have a strong opinion either, but I went through the same logic
when reading the draft that you've listed above, and came to the same
conclusion... it's appropriate in the REGISTER URI because it will be
correct (and possibly even required) in the generated INVITE URI. So...
that's option #1.

The only thing that might be worth doing is modifying the draft to say
that "any URI parameters that are required to appear in the INVITE's
Request URI must be included in the REGISTER's Request URI, because the
registrar will never add them on its own. This could include
'user=phone' (and these examples do include it), or other URI parameters
that may be defined later to be used with E.164-type Request URIs".

-- 
Kevin P. Fleming
Digium, Inc. | Director of Software Technologies
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
skype: kpfleming | jabber: [email-masked]
Check us out at www.digium.com & www.asterisk.org

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From: Brett Tate <[email-masked]>
Date: Thu, 18 Mar 2010 12:48:06 -0700

In case it helps, here is a link concerning user=phone topic; it was recently discussed on sipcore and sip-implementors.

http://www.ietf.org/mail-archive/web/sipcore/current/msg01784.html 

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] On
> Behalf Of Elwell, John
> Sent: Thursday, March 18, 2010 10:16 AM
> To: [email-masked]
> Subject: [martini] Use of user=phone in gin draft
> 
> The examples in the gin draft include 'user=phone' in the contact URI
> registered with the SSP, e.g.: <sip:198.51.100.3:5060;user=phone;bnc>
> 
> I just wonder whether user=phone is appropriate here. The parameter
> makes a statement that the user part is a telephone subscriber number,
> which in this case, in the absence of a user part, is clearly not the
> case. However, when expanded and used in an inbound request (e.g.,
> <sip:[email-masked]:5060;user=phone>, it can be correct. In
> fact, because the draft is limited to fully-qualified E.164 numbers in
> the user part, the presence of user=phone will always be correct.
> 
> 2. Omit from the REGISTER request but require the registrar to add it
> when constructing the complete contact URI.
> _______________________________________________
> martini mailing list
> [email-masked]
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