The IESG has approved the following document: - 'Explicit Subscriptions for the REFER Method' (draft-ietf-sipcore-refer-explicit-subscription-03.txt) as Proposed Standard This document is the product of the Session Initiation Protocol Core Working Group. The IESG contact persons are Barry Leiba, Ben Campbell and Alissa Cooper. A URL of this Internet Draft is: https://datatracker.ietf.org/doc/draft-ietf-sipcore-refer-explicit-subscription/ Technical Summary The Session Initiation Protocol (SIP) REFER request, as defined by RFC3515, triggers an implicit SIP-Specific Event Notification framework subscription. Conflating the start of the subscription with handling the REFER request makes negotiating SUBSCRIBE extensions impossible, and complicates avoiding SIP dialog sharing. This document defines extensions to REFER to prevent the implicit subscription and, if desired, replace it with an explicit one. 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- clarifications) 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 the shepherd's 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 document shepherd is Paul Kyzivat. The area director is Ben Campbell.
