https://app.kbone.net/vault/rfc/docid/7505
RFC6910: Completion of Calls for the Session Initiation Protocol (SIP)
Internet Engineering Task Force (IETF) D. Worley Request for Comments: 6910 Ariadne Internet Services, Inc. Category: Standards Track M. Huelsemann ISSN: 2070-1721 R. Jesske ...