https://app.knowbase.one/vault/rfc/docid/6580
RFC6050: A Session Initiation Protocol (SIP) Extension for the Identification of Services
Internet Engineering Task Force (IETF) K. Drage Request for Comments: 6050 Alcatel-Lucent Category: Informational November 2010 ISSN: 2070-1721 A Session Initiation Protocol (SIP) Extensio...