Currently only A and B scenarios are supported. There will be more in future.
Scenario A
Terminals connect to Server via application’s built-in OpenVPN client’s secure channel. This is a preferred deployment by the operators that don’t have dedicated routers in their ATM machines that have VPN capability features.
Scenario B
Terminals connect to Server via VPN that is being provided by additional hardware such as router. This scenario is considered as more secure then A as the VPN configuration is NOT distributed by CAS.
More Notes
Gate service
Listens for terminal’s pairing requests. In case of successful pairing gate service sends terminal VPN configuration including the information on where to connect to master service.
Master service
Listens to terminal’s requests. Answers only terminal requests that are coming from trusted ( paired ) devices.
Admin service
Listens to user's browser requests. Enables CAS users to configure ATMs remotely and inspect processed transactions.
Extensions
Very powerful way how to extend existing server’s functionality. More can be read here.