Subject: [Sipping] Diversion header

From: "Romel Khan" <[email-masked]>
Date: Mon, 21 Jul 2003 11:55:12 -0400

Is there any SIP header defined in any SIP RFC or Internet Draft that can include the address of the 1st callee, who redirected the call using 302, in the 2nd outgoing INVITE? 

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From: Cullen Jennings <[email-masked]>
Date: Sun, 27 Jul 2003 19:05:10 -0700

I assume your question is there some way for  for the final destination that
receives the call to know the who the 1st callee was that had some device in
the network redirect the call elsewhere.

The answer is YES - there has been a lot of confusion over this so think
about my answer carefully - it will seem counter intuitive at first. The
answer is the "To" header but it will take me a second to explain why.

Imagine case 1 where A send a call to proxy B,  that sent to to C. Now C
sent a 302 back B and B then forked the call to D. The To header in the
message D receives will still have the To set to C. C is the element that
sent the first 302.

Now imagine a case (like your question) where there is not a recursive
proxy. The 302 will go all the way back to A. Now A forms a new invite to
but it can leave the To header set to the same thing it was in the original
message (C in this case). When the message arrives at D, the To header will
be set to C.

If D was a voice mail system, it might be able to know to act on behalf of C
instead of some other entity.

There are more complex things that relate to your request. Mary Barnes has
been moving the history work along
http://www.ietf.org/internet-drafts/draft-ietf-sipping-req-history-04.txt

There is some work on QSIG mappings with diversion
http://www.ietf.org/internet-drafts/draft-elwell-sipping-qsig2sip-diversion-
00.txt

There is a draft-levy-sip-diversion which I (and many others) believe has a
pretty much zero chance of being accepted or becoming a RFC. This work has
been superceded by the history work. Quite a few people do not support the
history work and it is moving very slowly. Don't expect any of this to
resolve quickly.

Give some careful thought to if the "To" header meets your needs and if it
does use - The To header is widely implemented :-)

Cullen

On 7/21/03 8:55, "Romel Khan" <[email-masked]> wrote:

> Is there any SIP header defined in any SIP RFC or Internet Draft that can
> include the address of the 1st callee, who redirected the call using 302, in
> the 2nd outgoing INVITE?
>