From: "Urquhart, Gord" <[EMAIL PROTECTED]>
Specifically I'm thinking of a case of call transfer, where A calls B,
B calls C and then transfers A to C.
When B sends the REFER request to A, what should the URI/URL in the
Refer-to header contain?
- the URI/URL from the Contact header contained in the 200 OK
returned from C to B in response to B's INVITE
OR
- the URI/URL from the To header of the INVITE B sent to C.
OR ....
First, the contents of the Refer-To header is what B wants A to put in
the request-URI of the INVITE that A will send to C. The skeleton of
the INVITE is:
INVITE C SIP/2.0
Replaces: xxx;to-tag=xxx;from-tag=xxx
Require: replaces
so the URI to be put in the Refer-To header is
C?Replaces=xxx;to-tag=xxx;from-tag=xxx&Require=replaces
Where the xxx's are the dialog identifiers of the dialog between A and
B.
Now what to use for C?
Since this request needs to only go to the UA C, we can use its
Contact address.
This assumes that the Contact is routable from A, but RFC 3261
requires that, and if C implements GRUU support, it's likely to be
true.
Dale
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