Technical Summary
The SIP REFER method relies on the SIP-Specific Event Notification
Framework. That framework was revised by RFC6665. This document
highlights the implications of the requirement changes in RFC6665,
and updates the definition of the REFER method, RFC3515, to clarify
and disambiguate the impact of those changes.
Working Group Summary
There was some controversy and difficulty in reaching agreement on this draft.
Before work on this draft and the companion draft (draft-ietf-sipcore-refer-
explicit-subscription) commenced, some (notably 3GPP) made attempts to use
existing mechanisms (RFC4488) to avoid the need for GRUUs. That mechanism as
insufficient on its own, and so was enhanced with particular conventions.
There was a desire to maintain compatibility with that work. This led to
careful word smithing. That has been discussed at length within the WG.
The results are now acceptable to all parties.
Document Quality
The shepherd is not aware of any implementations yet.
It is his understanding that 3GPP release 12 has a reference,
indicating that implementations can be expected.
This document has been thoroughly reviewed and discussed. Everyone
that had something to say has aired it.
Personnel
The shepherd is Paul Kizivat. The responsible AD is Ben Campbell.