Comtech EF Data MIDAS 4 System and Design - Manual (Page 27)

System and Design Manual, Revision 2
Solutions 2–3
The circuit is established immediately and remains active until specifically
terminated by the MIDAS operator.
Connectivity on
Demand
On-demand connectivity could be required for applications such as LAN
extension, file sharing, file/media/software distribution, desktop
videoconferencing, remote session, etc. MIDAS supports on-demand
connectivity that can be initiated through the node control modem’s user port,
MIDAS operator’s workstation, or automatic IP address routing.
Node Control
Modem User Port
Manual Request
An end user can request a circuit to be set up immediately by entering the
destination traffic node and channel identification, and the desired grade of
service (data rate, modulation, and the encoding scheme) through the node
control modem’s user port.
The Node Control Modem sends a request to the MIDAS Controller. On
receiving the request, MIDAS Controller validates the request, allocates
bandwidth and transmits power, and informs the participating traffic nodes of
the frequencies to be used for the circuit. On receiving the frequency
assignment, the Node Control Modems tune the corresponding traffic modems
and enable them to transmit and receive, respectively, leading to circuit
establishment.
The user can request termination of the circuit any time by entering the
termination command through the Node Control Modem’s user port. The
modem terminates the circuit locally and informs the MIDAS Controller. The
MIDAS Controller terminates the satellite circuit and releases the associated
hardware; Bandwidth frequency and Power allocation.
Customer
Equipment Interface
User Port Commands
In addition to RTS/DTR triggered circuit setup and termination, customer
equipment can also be programmed to send circuit setup and termination
requests to the Node Control Modem via the user port. When a circuit is
required, the customer equipment sends the setup request to the Node Control
Modem via the user port.