Session Announcement Protocol
The Session Announcement Protocol (SAP) is an experimental protocol for advertising multicast session information. SAP typically uses Session Description Protocol (SDP) as the format for Real-time Transport Protocol (RTP) session descriptions. Announcement data is sent using IP multicast and the User Datagram Protocol (UDP).
The announcement interval is cooperatively modulated such that all SAP announcements in the multicast delivery scope, by default, consume 4000 bits per second. Regardless, the maximum announce interval is 300 seconds (5 minutes). Announcements automatically expire after 10 times the announcement interval or one hour, whichever is greater. Announcements may also be explicitly withdrawn by the original issuer.
Authentication, encryption and compression
SAP features separate methods for authenticating and encrypting announcements. Use of encryption is not recommended. Authentication prevents unauthorized modification and other DoS attacks. Authentication is optional. Two authentication schemes are supported:
Applications and implementations
- "SAP (v1 & v2): Session Announcement Protocol". Archived from the original on 2013-01-26. Retrieved 2012-04-06.
- M. Handley; C. Perkins; E. Whelan (October 2000). Session Announcement Protocol. RFC 2974.
- Viewing with Session Announcement Protocol (SAP), retrieved 2019-03-02
- "AES67-2013: AES standard for audio applications of networks - High-performance streaming audio-over-IP interoperability". Audio Engineering Society. 2013-09-11. Retrieved 2014-02-11.