1. A communications system comprising a first node ( 1 ) and a plurality of second nodes ( 2 ); in which the first node is connected to the plurality of second nodes for controlling the operation of the second nodes; in which the plurality of second nodes are physically interconnected ( 3 ) characterised in that; the plurality of second nodes are arranged in one or more logical interconnects ( 4, 5 ); in which the topology of the one or more logical interconnects is distinct from the topology of the physical interconnection; in which each second node ( 2 ) comprises means for identifying the corresponding logical successor node and logical predecessor node; in which each second node ( 2 ) comprises means for sending status messages to its logical successor second node and means for monitoring status messages received from its logical predecessor second node for determining the status thereof; in which each second node comprises application data and means for exchanging the application data with its logical successor node in the form of application messages in which at least some of the application messages function as status messages.