Subject: Re: [Ecrit] PSAP Callback - A New Beginning

From: Hadriel Kaplan <[email-masked]>
Date: Sun, 25 Mar 2012 07:26:16 +0000

On Feb 20, 2012, at 8:54 AM, Brian Rosen wrote:

> I don't have a problem with a nonce.
> We require TLS protection of signaling (because of privacy concerns carrying location and other personal information), which would protect the nonce from misuse.
> But, can't the UA and his system construct the contact to contain the nonce if it wants to, with no involvement of the PSAP?
> 

It could, but there's zero guarantee it will make it to the PSAP's end system, to be used for the callback.  B2BUAs along the way can (and often do) replace the INVITE's Contact.

-hadriel