In 1998, the Internet Engineering Task Force (IETF) published the specification for a Session Description Protocol or SDP as a format that describes parameters for streaming media. The original IETF Proposed Standard was updated in 2006 as RFC 4566. Although the SDP was created as a feature of Session Announcement Protocol (SAP), it can be used with Real-time Transport Protocol, Real-time Streaming Protocol (RTSP), and Session Initiation Protocol, as well as a standalone protocol. Parameter negotiation, session announcement and session invitation are included in the descriptive sessions from the SDP protocol. Rather than transmit data like other types of protocols, an SDP negotiates between media type endpoints, format and properties involved. A session begins when a connection is established, and the session is terminated only after every endpoint is no longer participating.