Subject: [Ecrit] draft-patel-ecrit-sos-parameter

From: "Patel, Milan" <[email-masked]>
Date: Tue, 9 Feb 2010 07:22:54 -0500

Hi,

At the previous meeting, it was requested that a feedback mechanism is
introduced to allow the UA to know if the registrar supports the
emergency registration extension or not (e.g. use of option-tag). It
seems from a 3GPP point of view this is not important. However, I can
understand that for other reg-type values, it may be useful to introduce
such feedback mechanism. 

In order to progress this draft (since this seems to be the only
sticking point), I propose the following:

UA may include an option-tag (name to be decided) in the Supported
header field, if the UA needs to know if the reg-type URI parameter is
supported by the registrar. The registrar returns the option-tag in the
200 (OK) upon successful registration if the extension is supported. 

Note, I am proposing this mechanism is introduced as an option...not
mandating the UA must include the option-tag during such registration.
Additionally, I am not including the option-tag in the Required header
field since if the emergency registration is not supported at the
registrar, fall back to normal non-emergency registration should occur -
not the failure of registration. 

Please let me know what you think. I will start on the revision. 

Best regards,

Milan

---

From: "Leis, Peter (NSN - DE/Munich)" <[email-masked]>
Date: Tue, 9 Feb 2010 15:51:43 +0100

hello Milan,

I do support your approach as outlined below.

Peter

________________________________

From: [email-masked] [mailto:[email-masked]] On Behalf
Of ext Patel, Milan
Sent: Tuesday, February 09, 2010 1:23 PM
To: [email-masked]; [email-masked]
Subject: [Ecrit] draft-patel-ecrit-sos-parameter

Hi,

Best regards,

Milan

---

From: "John-Luc Bakker" <[email-masked]>
Date: Thu, 11 Feb 2010 10:36:42 -0600

Hi Milan,

What would a UA do if a SIP message is received and the option-tag is
included in the "unsupported" header field? Should a 3GPP UA the not use
"draft-patel-ecrit-sos-parameter" in that case? 

Regards,

                John-Luc

--- 
John-Luc Bakker 
Standards Manager 
Research In Motion 
BlackBerry: +1 (908) 463 7321 
Office: +1 (972) 373-1761 
Internal: (820) 63761 
E-mail: [email-masked] 

From: [email-masked] [mailto:[email-masked]] On Behalf
Of Patel, Milan
Sent: Tuesday, February 09, 2010 6:23 AM
To: [email-masked]; [email-masked]
Subject: [Ecrit] draft-patel-ecrit-sos-parameter

Hi,

Best regards,

Milan

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---

From: "Patel, Milan" <[email-masked]>
Date: Thu, 11 Feb 2010 11:51:41 -0500

Hi,

As a result of today's interim meeting, we decided that the next version
of the draft will not include the feedback mechanism since it is not
required by 3GPP. Furthermore the next version of the draft will give
some explanation on the backwards compatibility case and what occurs at
the registrar and how the UA proceeds with the emergency call, once
registered. Also, it will be further clarified why the sos parameter is
used in the emergency registration in order to clear up this confusion
and help non-3GPP folks understand further the requirements.

John-Luc, the lack of support of the URI parameter at the registrar does
not impact the UA's ability to place an emergency call. The registration
is handled as a normal non-emergency registration. If the UA was
previously registered, then if the IMS system is pre-release 8, the
current registration would be overwritten by this new registration. One
use of the sos parameter  is to prevent this, but if you can't
distinguish emergency registration at the registrar, the result is the
registration is handled by normal registration procedures. We can't let
lack of support of the URI parameter at the registrar result in a failed
registration. 

Best regards,

Milan

From: John-Luc Bakker [mailto:[email-masked]] 
Sent: Thursday, February 11, 2010 4:37 PM
To: Patel, Milan; [email-masked]; [email-masked]
Subject: RE: [Ecrit] draft-patel-ecrit-sos-parameter

Hi Milan,

Regards,

                John-Luc

--- 
John-Luc Bakker 
Standards Manager 
Research In Motion 

Hi,

Best regards,

Milan

--------------------------------------------------------------------- 
This transmission (including any attachments) may contain confidential
information, privileged material (including material protected by the
solicitor-client or other applicable privileges), or constitute
non-public information. Any use of this information by anyone other than
the intended recipient is prohibited. If you have received this
transmission in error, please immediately reply to the sender and delete
this information from your system. Use, dissemination, distribution, or
reproduction of this transmission by unintended recipients is not
authorized and may be unlawful.