A protocol intended for the description of multimedia sessions for purposes of session announcement, session invitation, and other forms of session initiation. Described in IETF RFC 2327, SDP is used to advertise multimedia conferences and communicate the conference addresses and tool-specific information required for participation. SDP defines the characteristics and parameters of a multimedia session, but does not incorporate a transport protocol. Rather, SDP relies on transport protocols such as Hypertext Transport Protocol (HTTP), Session Initiation Protocol (SIP), and Real-Time Streaming Protocol (RTSP). See also HTTP, IETF, multimedia, protocol, RTSP, session, and SIP.
(Session Description Protocol) An IETF protocol that defines a text-based message format for describing a multimedia session. Data such as version number, contact information, broadcast times and audio and video encoding types are included in the message. Designed originally for describing multicast transmissions in the Mbone, SDP is also used by the RTSP streaming protocol and SIP and MGCP IP telephony protocols. See SDP, Mbone, RTSP, SIP and MGCP/MEGACO.