SDP: Session Description Protocol

Description

SDP describes multimedia sessions (e.g., use of codecs and receiver IP addresses and ports). It is used by SAP, SIP, RTSP and H.332.

Standards

RFC 2327: SDP: Session Description Protocol

Addresses

sap.mcast.net = 224.2.127.254 at port 9875

For local scope groups, at 239.255.255.255. In general, the highest address in all administrative scope zones should be used.

Implementations

Cisco (Precept)

You put the unicast address of the server into the c= line in a .SDP file. You can give that .SDP file as a command-line argument. Actually, it's the caudio= or cvideo= line since the format of the .SDP file is non-standard. This is due to an early decision to allow using Microsoft's .INI file parser. We are going to reverse that decision and change to the standard format in an upcoming release. You can get examples of the format in the GUIDE.TVG file that is fetched by IP/TV from the Program Guide (e.g., here at Precept).

sdr

Related Work

IETF work on content negotiation (RFC 2506, RFC 2533, etc.)
W3C work on client capability descriptions
"description logics", whose fundamental computation is a subsumption over sets of values described by restricted logical expressions. This was used many years ago in industrial contexts (look for CLASSIC).
W3C/DARPA/EU work on an XML language DAML+OIL for conveying DL-type descriptions
Annodex " hyperlinking, searching, and compositing infrastructure to time-continuous data, enabling e.g. video surfing, searching for clips of audio and video files using ordinary Web search engines, or on-the-fly composition of a video on a Web server from previously annodexed clips."

Internet Technical Notes and Resources

Last updated by Henning Schulzrinne