>>>>> Paul Kyzivat <[EMAIL PROTECTED]> wrote:

> Right. Lets take an example:
> Assume call is initially To: sip:[EMAIL PROTECTED]
> Alice forwards it to sip:[EMAIL PROTECTED] by putting that into the R-URI. 
> (To 
> URI is unchanged.)
> The call then arrives at the softswitch for biloxy.com.  The softswitch 
> then rewrites the R-URI with the contact for Bob's device: 
> sip:bobphone.biloxy.com.
> When the invite reaches the phone, it tries to use the To-uri to figure out 
> which line the call was addressed to. But it is expecting it to be either 
> sip:[EMAIL PROTECTED] or sip:[EMAIL PROTECTED] It is not expecting 
> sip:[EMAIL PROTECTED] and so can't figure out which line was intended.

This example shows only that any approach has its limited usage
scope and won't work when is used in inappropriate way. And the
main point is final UA ignorance of target. If this were, for
example, Bob's call center which proceeds secretary service for its
subscribers including Alice, it can use any header field to detect
what target was original to this request - if it sees Alice in
h_To, it would accept calls as targeted to Alice, use Alice's
incoming voicemail pool and even greet as "Alice enterprises,
please leave your message after beep". But you explicitly denied
its intelligence to distinguish calls using h_To, and that's your
choice, not its.

>       Paul
-- 
Valentin Nechayev
PortaOne Inc., Software Engineer
mailto:[EMAIL PROTECTED]
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