Optelecom-nkf Siqura C-54 E-MC User Manual page 49

Using the internal web pages
Note on FloodGuard: FloodGuard is a stream control mechanism that can be enabled/disabled
independently for each video and sampled data transmitter. FloodGuard will throttle the transmitter
when it no longer receives control messages from the receiver, thereby preventing the transmitter from
flooding the network.
FloodGuard only works when enabled on both the transmitter and the receiver, and when the transmitter
sends to a unicast address.
When a transmitter is enabled, it opens a control receive port with the port number equal to its source
port number + 1. This port listens for control packets from the destination receiver. When no FloodGuard
packets come in during the time set for the FloodGuard throttle delay, the receiver is expected to have
disappeared (powered off, receiver disabled, network problem etc.) and the stream is 'throttled'. In
throttled mode the transmitter will - in order to contact the intended receiver (again) - send empty
packets into the network at an interval determined by the FloodGuard throttle interval parameter. After
reception of a valid FloodGuard packet the transmitter will immediately resume streaming.
Encoder
Stream
manager
Transmitter #
Figure 7.19 Stream manager and FloodGuard
- 45 -
Enable
Stream bandwidth limit
Keep alive interval
Low latency
FloodGuard throttle delay
FloodGuard throttle interval