Network switch with head of line input buffer queue clearing

A network switch for routing data transmissions between network stations, the network switch comprising:

• a plurality of input ports, each including a memory for receiving and storing incoming data transmissions from at least one of said network stations;
• a plurality of output ports;
• routing means for selectively providing a route for conveying data transmissions in the memory of any one of said input ports to any other of said output ports,
• wherein whenever any data transmission stored in an input port's memory becomes the longest-stored data transmission in that memory, that input port transmits a routing request to the routing means requesting a route for conveying that longest-stored data transmission to a selected one of the output ports,
• wherein each input port removes and discards a longest-stored data transmission in its memory when its memory's unused storage capacity fall below a predetermined threshold level before the routing means establishes a route for conveying the longest-stored data transmission to one of the output ports, each input port otherwise forwarding its longest-stored data transmission from its memory via the route established by the routing means, and
• wherein said routing means stores each routing request received from each input port, discards a currently stored request from any input port when that input port subsequently transmits another routing request to the routing means before the routing means provides a route requested by the currently stored routing request, and otherwise discards a currently stored routing request from any input port only after providing the route requested thereby.