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Join draft finished WGLC last week:
ZERO comments — Does anyone care?
No open issues
Who’s read it?
Who’s implemented it?
Who’s planning to implement it?
Join Header Status
RFC 3515 says it is OK to put almost any arbitrary URI in a Refer-To header
arbitrary schemes
specific SIP methods
in or out of a dialog
preloaded SIP headers
What does that mean?
How do I authorize this?
Semantics of REFER
REFER in a dialog, Refer-To method=INVITE
REFER outside dialog, Refer-To method=INVITE
REFER with other methods: REGISTER, SUBSCRIBE, MESSSAGE
Nested REFERs
Refer-To: <http://> (targeted to dialog)
Refer-To: <http://> (not to a dialog)
Refer-To: <sip:[email protected];response=486>
What semantics make sense?
Transfer
Click to Dial
Move Sub
Remote Transfer
Fetch content
Send Busy
Option 1: Send REFER on existing dialog
Option 2: Use a separate GRUU per conversation. (This gets cumbersome very fast. Requires lots of target refresh requests.)
Option 3: Use explicit Refer-To header parameters:
Refer-To: <http://foo.com/>;call-id=123 ;remote-tag=abc;local-tag=xyz
How do you put REFER requests in a
context?
Most uses of REFER other than transfer are unlikely to work on today’s UAs
Suggest that we define semantics of cohesive baskets of REFER functionality. Use option-tags to make sure these are supported.
Propose that we add the explicit dialog parameters to Refer-To header
Provide guidance: to what extent is remote call control, and remote UI invocation (app interaction) OK.
How do we proceed?
