A Session Initiation Protocol (SIP) Response Code for Rejected Calls
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From: The IESG <email@example.com> To: IETF-Announce <firstname.lastname@example.org> Cc: The IESG <email@example.com>, Jean Mahoney <firstname.lastname@example.org>, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org Subject: Protocol Action: 'A Session Initiation Protocol (SIP) Response Code for Rejected Calls' to Proposed Standard (draft-ietf-sipcore-rejected-09.txt) The IESG has approved the following document: - 'A Session Initiation Protocol (SIP) Response Code for Rejected Calls' (draft-ietf-sipcore-rejected-09.txt) as Proposed Standard This document is the product of the Session Initiation Protocol Core Working Group. The IESG contact persons are Adam Roach, Alexey Melnikov and Barry Leiba. A URL of this Internet Draft is: https://datatracker.ietf.org/doc/draft-ietf-sipcore-rejected/
Technical Summary This document defines the 608 (Rejected) SIP response code, which informs a calling party that an intermediary has rejected their call attempt. This document also extends the Call-Info header field so that the caller may contact the blocking party if the rejection was in error. The 608 response code addresses the use case of call rejection by a call analytics engine or other automated process. This contrasts with the 607 (Unwanted) SIP response code, which is sent by a SIP user agent when a human indicates that the call was not wanted [RFC8197]. Working Group Summary The document is of interest to the STIR (Secure Telephone Identity Revisited) WG, but discussions were (mostly) kept to the SIPCORE mailing list since the document covers a SIP extension. Sometimes cross-posting was not successful and some discussions occurred only on the STIR mailing list. All feedback that was discussed on the STIR mailing list was incorporated into the document, however. Document Quality One of the authors (Bhavik Nagda) implemented this solution in Kamailio, which is an open source SIP server. The implementation can be found at https://github.com/nagdab/608_implementation. There are also governmental agencies that are interested in the 608 response code feature. Reviewers and their contributions have been called out in the Acknowledgements section. Tolga Asveren provided substantial feedback on interoperability and security considerations. Personnel Jean Mahoney is the Document Shepherd. Adam Roach is the Responsible Area Director.