Site home page
Get alerts when Linktionary is updated
Book updates and addendums
Get info about the Encyclopedia of Networking and Telecommunicatons, 3rd edition (2001)
Download the electronic version of the Encyclopedia of Networking, 2nd edition (1996). It's free!
Contribute to this site
Electronic licensing info
SDP (Session Description Protocol)
Note: Many topics at this site are reduced versions of the text in "The Encyclopedia of Networking and Telecommunications." Search results will not be as extensive as a search of the book's CD-ROM.
SDP is a protocol that describes a format for conveying descriptive information about multimedia sessions. When a user wants to join a conference, he or she needs a way to know the multicast group address and the UDP port address for the conference.
SDP was designed as a session directory tool that could be used to advertise multimedia conferences, and communicate the conference addresses and conference tool-specific information necessary for participation. At the same time, SDP was designed for general-purpose use so that it could be used for a wide range of network applications.
This information includes session name and purpose, session time, type of media (voice or video), media format (MPEG, for example), transport protocol and port number, bandwidth requirements, and contact information. SDP is not a transport protocol, but relies instead on SIP (Session Initiation Protocol) or SAP (Session Announcement Protocol) to deliver the session information to destinations. For example, a caller can send SDP descriptive information in a SIP INVITE message. The callee then responds with acknowledgments regarding the descriptions that it can accept.
Copyright (c) 2001 Tom Sheldon and Big Sur Multimedia.