OASyS DNA Socket Server Relay Service

The OASyS DNA Socket Server Relay Service allows two different TCP clients to connect to two different ports such that the bytes received on one port are relayed to the other, and vice versa.

Typically, the service is used on AVEVA Enterprise SCADA systems in cases where, for example, a process such as Omnicomm needs to receive connections from remote systems that call into the AVEVA Enterprise SCADA system by connecting to a TCP port. Since Omnicomm does not allow external systems to connect to it (Omnicomm always initiates IP connections), the OASyS DNA Socket Server Relay Service provides a mechanism whereby Omnicomm can connect to the Relay Service, which in turn can listen for remote connections from the field. Once the remote connection is established with the service, any data from the field device on that connection is relayed to Omnicomm, and vice versa.

A port pair can operate in either blocking or non-blocking mode:

• Blocking Mode: Each port of the pair accepts one client.

• Non-Blocking Mode: Multiple clients can connect to a single port (Port A). Similarly, multiple clients can connect to the other port (Port B). All clients are served on a FCFS (First Connected First Served) basis.

One instance of the service can handle multiple port pairs.