Hi all!

A question about To tags. This is the scenario I have in mind:

* UA1 calls [EMAIL PROTECTED] via the proxy P.
* P knows that [EMAIL PROTECTED] should be forwarded to UA2.
* UA2 responds to the Invite with a 180 Ringing and has added a To tag to
the response.
* After a period of time, logic in P notices that UA2 hasn't answered the
call yet. Then P has instructions to try at UA3 instead, so it sends Cancel
to UA2 and sends the origianl Invite to UA3.
* UA3 now answers with 180 Ringing with a new To tag since it has no idea of
the To tag that UA2 sent.
* UA3 send 200 OK and the call is set up.

My quesiton is that isn't not allowed to change the To tag within a dialog
since it is used to identify a call? Is it possible to do my scenario? Could
it be solved in that way that before P forwards the Invite to UA3, it adds
tha To tag that UA2 sent in the first 180? I think I've read somewhere that
you are not allowed to put the To tag inside an Invite (if it is not an
re-Invite), is this correct? Should I solve the forward on no reply in some
other way?

Appreciate to hear your thoughts in this matter.

Regards,
Andreas

____________________________________
Andreas Bystrom
Computer Engineer

e-horizon Streaming Technologies
Stadshusplatsen 2, 4th floor
Box 172
SE 14922 Nynashamn

mail  : [EMAIL PROTECTED]
web   : www.e-horizon.se
phone : +46 8 524 201 80
mobile: +46 708 85 23 35
____________________________________

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