GarretCom’s substation routers have two principal modes of serial communications of transporting over a WAN, one routed and one non-routed. These two modes will co-exist on a common WAN in many implementations. SCADA Frame Forwarding is referring to the non-routable transport mode and some times call as Serial over Frame Relay (or Serial FR). This may best be thought of as a Frame Relay Multiplexing technology in the context of NERC CIP. Serial-FR encapsulates each RS232 or RS485 based serial data connection at a substation into a unique Serial-FR logical connection as a multiplexing technology. Each Serial-FR connection is then converted back to a native RS232/RS485 based serial interface, and then connected to a master of Serial-based SCADA. GarretCom has two families of substation routers, Magnum DX and DynaStar.
DynaStar/DX SCADA Frame Forwarding will work equally whether implemented using a frame relay network (cloud) or using point to point digital circuits from substation to control centers – either a carrier provided Frame Relay Service or a private frame relay network. No IP routing is provided over frame relay. The protocol ‘stack’ remains Serial over FR also without IP. The common trunks merge to frame relay PVCs via intermediary frame relay switching nodes when using a frame relay network. Serial FR using a relay network of frame, rather than relay of frame over dedicated digital circuits. Some GarretCom DynaStar can also provide relay of frame switching s well as frame relay access functionality.