Master Control Station -- Monitor/Control Station Communications Architecture

Links within this architecture are either T1 or fractional T1 data links, with exact capacity to be determined from required data traffic between the Master Control Station and that station. Each link will be sized to be capable of handling 200% of the data volume anticipated between the Master Control Station and that station. The network protocol used is TCP/IP, with a central router at the Master Control Station and other routers at each monitor station. The recommended topology is shown below.

This network topology was chosen to provide a high degree of availability of communications between each Monitor/Control Station and the Master Control Station. The topology selected (star and ring) provides the following advantages:

• The recommended topology requires a total of ten (10) circuits, the same as dual direct connectivity between each Monitor/Control Station and the Master Control Station.
• Other than the Master Control Station router, there is no single point of failure that can isolate any Monitor/Control Station.
• Each Monitor/Control Station has five possible paths to get data to the Master Control Station; the primary is the direct link, while available alternates are through other stations.
• No Monitor/Control Station can lose connectivity with the Master Control Station unless it either (1) loses all incoming links, or (2) a total of four links in the network are lost, causing network bifurcation, and the affected station is in the resulting subnetwork that does not contain the Master Control Station.
• A private network does not allow for attepts at external penetration via normal Internet hacking attempts.
• Links in this network should be encrypted. If proper key management is followed, this also provides protection against interception, authentication of transmissions, and data integrity. A symmetric keying system is recommended due to the data rates involved. Keys should be unique to each link (to limit problem in the event of compromise) and should be distributed electronically due to geographical dispersion.
• Known primary routes and possible alternate routes, coupled with light network load, gives tight bounds for average propagation time, making network behavior highly predictable.

The recommended protocol stack for this layer is the standard TCP/IP network stack. DCE middleware components will be present at each end host to provide a standardized API/RPC environment. The protocol stack would be the same at each site.