Protocol Action: 'Session Initiation Protocol Extension Header Field for Service Route Discovery During Registration' to Proposed Standard

[The IESG <iesg-secretary@ietf.org>]

The IESG has approved the Internet-Draft 'Session Initiation Protocol 
Extension Header Field for Service Route Discovery During Registration' 
<draft-ietf-sip-scvrtdisco-04.txt> as a Proposed Standard. This document is 
the product of the Session Initiation Protocol Working Group. The IESG 
contact persons are Allison Mankin and Jon Peterson.

Technical Summary
                                                                                
            This document defines a SIP extension header field used in
            conjunction with responses to REGISTER requests to provide a
            mechanism by which a registrar may inform a registering User
            Agent (UA), that is, an end-user, of a service route that the UA
            may use to request outbound services from the registrar's domain.
                                                                                
            SIP has a Route Header which is used to loose source route
            messages, and this Service Route extension allows providers to
            offer plans in which a user can ensure that they visit a provider's
            proxy at which they registered. IETF protocols should neither favor
            nor preclude* such capabilities. Security for the user and the
            provider are provided by the use of the SIP sips: address of record
            mandating that the hops be carried over TLS, and use of S/MIME for
            the bodies in the messages.
                                                                                
                                                                                
Working Group Summary
                                                                                
            There was active review. This document was split out from
            the other direction, called the PATH header and worked on until
            it had adequate clarity and security. Its current version has
            good consensus.
                                                                                
                                                                                
Protocol Quality
                                                                                
        This document has been reviewed for the IESG by Rohan Mahy and
        and Allison Mankin. Some implementations were tested in recent
        interoperability events.