Subject: Re: SIP, voicemail, and UPT

From: John Hearty <[email-masked]>
Date: Tue, 22 Jun 1999 12:42 -0500 (CDT)

It sounds like you are considering the case where a caller wants to
terminate to a particular type of device.  If that is the case, look
at draft-ietf-mmusic-sip-caller-00.txt Caller Preferences and Callee 
Capabilities.

Date: Tue, 22 Jun 1999 10:38 -0500 (CDT)
From: "Adam B. Roach" <[email-masked]>
To: [email-masked]
Sender: [email-masked]
Subject: SIP, voicemail, and UPT

I'd like to get a feel for what the group thinks about the following.

Most UPT services (universal personal telephone number -- the
"dial one number and it'll find me" services) will search
through a list of destinations until they find a number that answers. 
They don't care *what* answers; any answer will terminate the search.

Since many numbers have an automatic roll-over to voicemail, an
answering machine, a pager, etc., these services have been
much less useful than they potentially could be.

How would you feel about an extension to SIP -- say, a "280 Voicemail"
response code -- which would help address this problem? Proxies
which implement UPT services could then choose to continue
searching after a 280 response. Since it's a 200-class response,
any clients which don't understand it are already required to
treat it as success, so nothing breaks, and no further requirements
are placed on clients.

(Thanks to Dean Willis for raising this issue originally).

-- 
Adam Roach, Ericsson Inc. |  Ph: +1 972 583 7594 | 1010 E. Arapaho, MS L-04
[email-masked]   | Fax: +1 972 669 0154 | Richardson, TX 75081 USA

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From: [email-masked] (Pradeep Malhotra)
Date: Tue, 22 Jun 1999 11:05:25 -0700

Hi,
	Proxies can start the search in parallel for all the possible locations
	of the user. Proxies can continue with the search for a finite time
	unless the highest priority location of the user has answered. The
	priority of the location could be registered with the server at the
	time of SIP registration. That way any services can be relatively
	priortised by the user. 
	
	In that case we will not require a special  "280 response code" 
	and 200 response code should suffice. 

regards,
pradeep

> From [email-masked] Tue Jun 22 10:43 PDT 1999
> Date: Tue, 22 Jun 1999 10:38:46 -0500 (CDT)
> MIME-Version: 1.0
> Content-Transfer-Encoding: 7bit
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>

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From: Sean Olson <[email-masked]>
Date: Wed, 23 Jun 1999 08:22:35 -0500 (CDT)

> 	and 200 response code should suffice. 

The problem with this approach is that the priorities you mention are set
by the callee and not the caller.

-----------------------------------------------------------------
Sean Olson            E-mail: [email-masked]
Ericsson Inc.         Voice: (972) 583-5472 
                      FAX: (972) 669-0154