OPTICAL NETWORK AND ARRANGEMENT AND METHOD IN SUCH NETWORK.

摘要

The present invention concerns an optical network which is arranged to ensure communication between nodes in a lower-order loop and a higher-order loop when there is an interruption in the lower-order loop or in the event of hub failure. Each lower-order loop consists of a bus network (5) with hubs and one or a plurality of nodes (A-D). Two optical fibres (1, 2) connect the nodes in each bus network (5) and are used for communication in opposite directions between the nodes. Each bus network comprises precisely two hubs (H1, H2) of which the first closes the bus network end at the first end thereof and the second closes the bus network at the other end. The hubs connect the bus networks (5) in a lower-order loop and join this loop to a higher-order loop. Each node in the bus network is arranged to communicate with each hub. The invention also concerns a process for channel allocation in the aforementioned optical network. The channel allocation can be carried out so that channels received in one node are re-used for transmission on the same fibre from the same node.