Patent ID: 7274660

Claim:
A method of flow control in a distributed switch fabric, the method comprising: detecting a congestion condition in a downstream transceiver port coupled to receive packets over a channel from a transceiver port, wherein the downstream transceiver port is comprised of a downstream receiver port and a downstream transmitter port, wherein detecting the congestion condition comprises the downstream receiver port detecting the congestion condition, wherein the transceiver port is comprised of a receiver port and a transmitter port; reporting the congestion condition to the transceiver port, and wherein reporting the congestion condition comprises: the downstream receiver port reporting the congestion condition to the downstream transmitter port; and the downstream transceiver port reporting the congestion condition to the receiver port; the transceiver port suspending transmission of the packets over the channel to the downstream transceiver port; the packets accumulating in a channel buffer of a traffic manager corresponding to the transceiver port; if the channel buffer reaches a threshold value, the traffic manager modifying transmission of the packets to the channel buffer; the downstream transceiver port detecting a clear condition; reporting the clear condition to the transceiver port; and the transceiver port resuming transmission of the packets to the downstream transceiver port, wherein if transceiver port resumes transmission of the packets prior to the channel buffer reaching the threshold value, the transceiver port suspending transmission of the packets operates transparently to the traffic manager.