determine the shortest path between encoder and decoder to route the multicast stream. On
the decoder side, the user requests a stream from the encoder, using an SSM aware RTSP
client (such as VLC, for example).
For more information on source-specific multicast, refer to the following.
22.2
Multi-unicasting
As an alternative to multicasting, the BC840-MC features 'multi-unicasting', that is - sending
out up to 4x2x3 independent copies of video, and sending and receiving four data streams. If
the bit rates selected are moderate, it may be more convenient to use this mechanism instead
of multicasting, even though the network gets more signal to carry from the encoder.
When such a destination is removed, the source also stops sending the corresponding stream.
If the input channel of a destination is disabled without disabling the source, source
transmission will be throttled, but not disabled (this behaviour is selectable through the
FloodGuard settings). The source downsizes the stream by sending empty UDP packets until a
wake-up call is received. The empty packets, of course, carry the relevant IP/port information.
22.3
Port numbers
A valid UDP port number in a TKH Security A-, C-, S-, and V-series system is an unsigned 16-
bit integer between 1024 and 65536. Generally, you do not need to select other than the
default receiver port numbers as given in the MIB (Management Information Base). If you
want to change these receiver port numbers for some reason, use even numbers. A given
receiver port number N is associated with the port number N+1, through which control
information is returned to the source.
Eligible port numbers in general are within the range indicated above, with some exceptions.
Those within the 3000-10000 range are reserved and/or hard-coded, or may become
reserved, so only 10000-65535 are generally safe. Default port numbers (used by receivers)
are shown in the following table.
General
Example
Video
50xxx
Video
50010
Audio
51xxx
Audio
51010
Data
52xxx
Data 1
52010 (RS-4xx)
Data 2
52020 (RS-232)
CC
53xxx
CC 1
53010
CC 2
53020
Default port numbers
TKH Security MX applications using automatic port number allocation may use 55000 and up.
Multicasting
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