Session the Announcement Protocol (SAP) is network minutes from the range of the IP-Telefonie, which supports multicast Multimediasitzungen and other multicast meetings and which appropriate meeting configuration passes on on in question coming participants. It was developed of the IETF and is described in the RFC 2974. The SAP sends thereby periodically announcement packages to those generally admitted ("“wave known"”) multicast address (sap.mcast.net = 224.2.127.254) on the appropriate haven (standard: 9875). The SAP Client horcht on this haven, in order recognize possible multicast meetings and to assume to be able.

Structure of a SAP package

• V - 3 bit - version number, must be set to 1
• A 1 bit - ADDRESS type, can be 0 or 1
  • 0 field Originating SOURCE contains IPv4-Adresse (32 bits)
  • 1 - Field Originating SOURCE contains IPv6-Adresse (128 bits)
• R - 1 bit - Reserved, is set by SAP to 0 and ignored by SAP Clients
• T-1 bit - Message type, can be 0 or 1
  • 0 package for the announcement of a meeting
  • 1 - Package for the deletion of a meeting
• E - 1 bit - Encryption bit, can be 0 or 1
  • 0 of the Payload is not coded, the Timeout field may be missing
  • 1 - The Payload is coded, the Timeout field must the header be added
• C - 1 bit - Compressed bit, if 1 is set, then the Payload compressed
• Authentication length - 8-bits - indicates the number of which follow the header and contain Authentifizierungsdaten, on. If 0, then no Authentifizierungs header available
• Message Identifier Hash - 16 bits - is used together with the field Origination SOURCE, in order to receive a global clear Identifikator for this message.
• Origination SOURCE - 32 bits or 128 bits - the IP address of the author of the message. If field A 0 is set, here a IPv4-Adresse stands if 1, then a IPv6-Adresse.
• Timestamp - 32 bits - case of the Payload is coded, contains this field a time stamp, which prescribes, how long the message is valid. It is stored and in seconds indicated in the NTP format.
• Payload type - contains the MIME type (speak the data format) the Payloads. It is indicated and of a zero byte (ASCII NUL) is locked as ASCII stringer.
• Payload - contains the actual data (pay load) and is again into various Unterfelder divided.

See also

• SIP (session Initiation Protocol)
• SDP (session Description Protocol)
• IP-Telefonie

Related links

• RFC 2974

Articles in category "Session Announcement Protocol"

We found here 6 articles.

Related Websites

We found here 3 related websites.

• SAP (SAPv1 & SAPv2): Session Announcement Protocol Overview (RFC 2974)
  SAP: Session Announcement Protocol overview, commands, format and reference IETF 2974.


• SAP (Session Announcement Protocol) (Linktionary term)
  Description of SAP (Session Announcement Protocol) from Tom Sheldon's Encyclopedia of Networking and Telecommunications.


• Session Announcement Protocol (SAP)
  The Session Announcement Protocol (SAP) must be one of the simplest protocols around. To announce a multicast session, the session creator merely multicasts ...