Session Announcement Protocol (SAP) is a protocol to broadcast multicast session information. SAP was published
by the IETF as RFC2974.
The core
encapsulates Session Description protocol (SDP) as a description of
streaming media information. SDP was published by the IETF as RFC4566.
SAP/SDP
inserter sends periodically SAP/SDP announcements at Multicast address
239.255.255.255 and UDP port 9875. These announcements allow the
receivers which support SAP/SDP protocol to retrieve all the necessary
information to connect to all streaming multicast media
present.