Network switch including bandwidth controller

A network switch comprising a plurality of receive ports for receiving addressed data packets and a plurality of transmit ports for forwarding the addressed data packets and means responsive to data in said packets for directing received packets to said transmit ports, said switch including, in respect of at least one of said transmit ports:

• a plurality of bandwidth controllers each for a respective selected packet type, each bandwidth controller including
• means for diminishing an aggregate count in a first sense in response to the sizes of packets of said respective type destined for said one transmit port;
• means for continually augmenting said aggregate count in a second sense opposite said first at a selectable rate;
• means for making a comparison of said aggregate count with a threshold;
• and
• means responsive to said comparison for initiating discard of packets of said respective type before they can be forwarded from said one transmit port such as to limit the proportion of available bandwidth occupied by packets of said one type in respect of said one transmit port.