Comtech EF Data MIDAS 4 System and Design - Manual (Page 31)

System and Design Manual, Revision 2
Solutions 2–7
Figure 2-2. Congestion Reduction
The network operation for congestion reduction is to connect the routers via
the primary terrestrial circuit. The router’s overflow port is connected to the
traffic modems via synchronous serial interface. The satellite circuit is not
active. Router detects congestion, switches excess traffic to overflow port and
raises RTS/DTR of the traffic modem. Node Control Modem detects
RTS/DTR active state-of-the traffic modem; requests MIDAS Controller for
overflow circuit.
MIDAS Controller allocates bandwidth, power, and establishes overflow
circuit within seconds (preempting low priority circuits if required). The router
detects end of congestion and deactivates RTS/DTR of the traffic modem.
Node Control Modem detects RTS/DTR deactivation in the traffic modem,
terminates the circuit locally and informs the MIDAS Controller. MIDAS
Controller terminates the satellite circuit and releases the associated resources.