Network switch with arbitration sytem

A network switch for routing data packets between a plurality of network stations, comprising:

• a plurality of input ports interconnected to form an input token passing ring, each input port including means for passing the input token to a succeeding input port of the ring after receiving an input token from a preceding input port of the ring, and each input port including means for receiving and forwarding data packets from corresponding network station;
• a plurality of output ports interconnected to form an output token passing ring, each output port including means for passing an output token from a succeeding output port of the ring after receiving the output token from a preceding output port of the ring, and each output port including means for receiving and forwarding data packets to a corresponding network station;
• a switching system connected to said input and output ports for receiving packets forwarded by said input ports and selectively routing them to said output ports in accordance with input routing data;
• and
• a global bus interconnecting said input ports, said output ports and said switching system;
• wherein when one of said output ports receives the output token and is idle (not currently receiving a packet), it signals the input ports via said global bus to begin passing the input token, and wherein when a token receiving input port has received a packet to be forwarded to the token receiving output port, the token receiving input port sends routing data to said switching system via said global bus.