Session Initiation Protocol (SIP) INFO Method and Package Framework
This document defines a method, INFO, for the Session Initiation Protocol (SIP), and an Info Package mechanism. This document obsoletes RFC 2976. For backward compatibility, this document also specifies a "legacy" mode of usage of the INFO method that is compatible with the usage previously defined in RFC 2976, referred to as "legacy INFO Usage" in this document. [STANDARDS-TRACK]