Subject: [Ecrit] draft-winterbottom-ecrit-direct

From: Marc Linsner <[email-masked]>
Date: Wed, 28 Oct 2009 09:00:30 -0400

So, to be sure I¹ve got this straight.

1. The primary mechanism outlined in this draft enables a Œfree-agent¹ SIP
UA to register with an ESRP such to enable PSAP call-back.
2. The secondary purpose of this draft is to simply document (in one place)
how a SIP UA could make emergency calls without using a VSP.

A) This assumes the PS jurisdiction is comfortable with implementing a
Registrar along side their ESRP (in support of #1).
B)  If in fact the SIP UA is used for making non-emergency calls, the AOR
used for the non-emergency calls would not be known by the ESRP/PSAP.
C)  Longer term Œcall-back¹, outside the suggested 60 minutes, would not be
possible due to lack of UA AOR information.

-Marc-

---

From: "Thomson, Martin" <[email-masked]>
Date: Thu, 29 Oct 2009 05:57:32 +0800

Hi Marc,

Just on the one point:

> C)  Longer term ‘call-back’, outside the suggested 60 minutes, would not be possible due to lack of UA AOR information.

This is one aspect that could be made clearer.  It should be:

   [[The existing statement is to this effect: The ESRP/registrar 
   selects a registration period based on local policy.]]  The 
   emergency client MUST accept a registration for at least 60 minutes,
   but MAY accept longer registrations based on its own policy.

(I’ll note that this is virtually identical to the mechanism adopted by 3GPP for emergency registrations, except for the recognition that a client is permitted to set policy in this regard also.)

--Martin

---

From: Marc Linsner <[email-masked]>
Date: Wed, 28 Oct 2009 18:51:42 -0400

Martin,

Thanks!

-Marc-

On 10/28/09 5:57 PM, "Thomson, Martin" <[email-masked]> wrote:

> (I¹ll note that this is virtually identical to the mechanism adopted by 3GPP
> for emergency registrations, except for the recognition that a client is
> permitted to set policy in this regard also.)
> 
> --Martin