SYSTEM FOR CONTROLLING DOUBLE RING NETWORK COMMUNICATION

PURPOSE:To prevent the collision of a packet and to realize the transmission of the packet of optional length without providing a special node by connecting a link for transmission and a link for returning to plural nodes and controlling the link with the aid of the switching part of each node. CONSTITUTION:A double ring network is constituted by connecting the nodes 3-1-3-(n) with the aid of the link 1 for transmitting the packet and the link 2 for returning an impact packet. The testing part 4 of each node has a function identifying the packet and controlling the switching part 7. When the testing part 4 identifies the packet for its own node, it fetches the packet to a reception part 5 and does not relay-transmit it to the node of a downstream side. As the packet is not transmitted to the link 1, the node of the downstream side can transmit the packet. As the node which transmits the packet switches and connects the receiving side of the link 1 to the link 2 and returns the packet which is transmitted from the node of an upstream side, it judges that the collision occurs when it receives the packet which its own transmits. Therefore, the packet of the optional length can be transmitted without taken or the like and the impact can be easily detected.