Network switch with dynamic backpressure per port

Abstract

A network switch including a plurality of network ports for communicating data packets, each port including logic for receiving a backpressure indication and for transmitting a jamming sequence to terminate transmission of a data packet being received. The switch includes a memory for temporarily storing data packets received by the ports, and a switch manager for determining one or more threshold conditions of the memory, for determining if a new data packet being received is to be stored in the memory for transmission by another port, and if so, for providing the backpressure indication to terminate the new data packet if a backpressure signal indicates that a threshold condition would be violated by storage of the new data packet. The jamming sequence is not sent if the packet is not intended to be stored in the switch, so that network devices coupled to a single port may continue to communicate to each other. The remaining ports of the switch are not effected. The threshold conditions include, among others, a maximum number of sectors storing data packets received by a port in a receive sector chain, a maximum number of data packets stored in the memory in a transmit packet chain, a minimum number of free sectors available in the memory for storage of data packets, and a maximum number of broadcast data packets stored in the memory.