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The BC840-MC includes a SAP announcer. The Session Announcement Protocol is used to
advertise that a media stream generated by the BC840-MC is available at a specific multicast
address and port. For more information about SAP, see the note below.
Item
Enable SAP
Stream name
Stream dest. IP
Stream dest. port
Stream DSCP field
Multicast TTL
Announcement
interval
Session scope
Multicast IP range
Note on the Session Announcement Protocol (SAP): SAP, defined in RFC 2974 (see RFC
2974 - http://www.ietf.org/rfc/rfc2974.txt), is a protocol for advertising multicast session
information. A SAP announcer periodically broadcasts announcement packets which include
the session description information of multicast sessions presented by the announcer. SAP
uses the Session Description Protocol (SDP) as the format of the session descriptions. The
announcement is multicast with the same scope as the session it is announcing, ensuring
that the recipients of the announcement are within the scope of the session the
announcement describes. SAP listening applications can listen to the announcements and
use the information to construct a guide of all advertised sessions. This guide can be used to
select and start a particular session. The SAP announcer is not aware of the presence or
absence of SAP listeners.
Description
When selected, session announcements are sent at the frequency
determined by the Announcement interval parameter and the
media stream is transmitted to the multicast IP address specified in
the Stream dest. IP address box.
Enter a descriptive name to identify the media stream.
Enter the multicast IP address the media stream is to be sent to.
The address must be within the range defined by the Multicast IP
range parameter.
The destination port number. Default: 1024.
Range: [0...63]. See the note on DSCP.
Range: [0...127]. Specify the number of routers (hops) that
multicast traffic is permitted to pass through before expiring on the
network.
Determines the frequency of announcements.
Global, the default session scope, sets the Multicast IP range
parameter to 224.2.128.0 - 224.2.255.255 (IPv4 global scope
sessions). A SAP listening application will recognize the global
scope and automatically listen for SAP announcements at the
224.2.127.254 multicast IP address.
The Administrative session scope allows you to enter a custom IP
range within the 239.0.0.0 - 239.255.255.255 (IPv4 administrative
scope sessions) range. For an Administrative session scope, the
multicast address for SAP announcements will be set to the highest
address in the relevant administrative scope. For example, for a
scope range of 239.16.32.0 - 239.16.33.255, the IP address
239.16.33.255 is used for SAP announcements.
See Session scope.
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