Difference between revisions of "SAP"

From VideoLAN Wiki
Jump to navigation Jump to search
m (HTML for RFC)
m (Line breaks)
Line 1: Line 1:
 
{{wikipedia|Session Announcement Protocol}}
 
{{wikipedia|Session Announcement Protocol}}
 
'''SAP''' stands for '''Session Announcement Protocol'''.
 
'''SAP''' stands for '''Session Announcement Protocol'''.
It is defined in [https://tools.ietf.org/html/rfc2974 RFC 2974].
+
It is defined in [https://tools.ietf.org/html/rfc2974 RFC 2974].<br />
 
It uses [[multicast]] to announce streams efficiently on a Local Area Network or on the [[MBONE]]:
 
It uses [[multicast]] to announce streams efficiently on a Local Area Network or on the [[MBONE]]:
 
any computer on the network can receive announces from all others without any manual configuration.
 
any computer on the network can receive announces from all others without any manual configuration.
Line 8: Line 8:
  
 
This technique allows a lot of server to emit streams (often multicasted) and announce them on the network.
 
This technique allows a lot of server to emit streams (often multicasted) and announce them on the network.
Clients on the network can then listen for these announces.
+
Clients on the network can then listen for these announces.<br />
VLC can do this with the "SAP" service discovery plugin.
+
VLC can do this with the "SAP" service discovery plugin.<br />
 
You then get a listing of all these streams and can simply ''tune'' into the stream of your choice.
 
You then get a listing of all these streams and can simply ''tune'' into the stream of your choice.
  
Because SAP uses [[multicast]] (as do [[UPnP]] and Apple [[Bonjour]]), it can normally only operate on a Local area network.
+
Because SAP uses [[multicast]] (as do [[UPnP]] and Apple [[Bonjour]]), it can normally only operate on a Local area network.<br />
 
Unless your computer is connected to the [[MBONE]], you cannot use SAP to advertise your streams onto the Internet, nor can you receive streams from other places.
 
Unless your computer is connected to the [[MBONE]], you cannot use SAP to advertise your streams onto the Internet, nor can you receive streams from other places.
 
  
 
== See also ==
 
== See also ==

Revision as of 02:15, 19 April 2019

SAP stands for Session Announcement Protocol. It is defined in RFC 2974.
It uses multicast to announce streams efficiently on a Local Area Network or on the MBONE: any computer on the network can receive announces from all others without any manual configuration.

SAP conveys SDP's to describe streams parameters. This can include an RTSP control URL to use for setting up the stream, or a multicast group address to subscribe to. The SDP also includes port numbers and audio/video codecs parameters, and a stream name, etc.

This technique allows a lot of server to emit streams (often multicasted) and announce them on the network. Clients on the network can then listen for these announces.
VLC can do this with the "SAP" service discovery plugin.
You then get a listing of all these streams and can simply tune into the stream of your choice.

Because SAP uses multicast (as do UPnP and Apple Bonjour), it can normally only operate on a Local area network.
Unless your computer is connected to the MBONE, you cannot use SAP to advertise your streams onto the Internet, nor can you receive streams from other places.

See also