Patent ID: 7385919

Claim:
A local network comprising: at least two coupling devices and a redundancy manager, each of which comprises at least two ports, wherein the coupling devices and the redundancy manager are configured as layer 2 components with respect to an ISO OSI 7-layer model and are interconnected in a ring by a connection of two ports of respective adjacent devices, and wherein further, the redundancy manager is configured to send initial test messages into the ring at predefined intervals via two of the at least two ports of the redundancy manager with which it is connected to the ring and if the initial test messages sent by each one of the two ports are received by the other one of the two ports of the redundancy manager within a predefined time interval, to open the ring to create a linear topology and otherwise to close the connection, and wherein further, the redundancy manager is configured to indicate a corresponding ring opened or connection closed status in the initial test messages and at least one of the other coupling devices adjacent to the redundancy manager in the ring is configured as a redundancy manager observer to evaluate messages that it receives at one of its ports which is connected to the redundancy manager and to open the ring to create a linear topology if more than only the initial test messages have been received at the one port and the redundancy manager has indicated the ring opened status in an immediately preceding received initial test message.