Patent ID: 7092387
Filing Date: 2006-08-15
Classification: H04L

Abstract:
1. A switch controller inside a switch device capable of easing network congestion, the switch controller has a plurality of ports and the switch device further includes a shared buffer and a plurality of physical layer devices (PHY), the shared buffer can be divided into a plurality of buffering units, the switch controller comprising: a buffer control device coupled to the shared buffer for assigning and releasing the buffering units; a plurality of port control devices coupled to the physical layer devices and the buffer control device, wherein each port control device has a one-to-one correspondence with the ports, the port control device that corresponds to a source port receives a network packet and then sends the packet to at least one of the buffering unit(s) for storage; a forwarding control device coupled to the port control devices, and a target port of the packet is determined according to a header of the network packet; and a queue control device coupled to the port control devices and the buffer control device, wherein the queue control device further includes a plurality of output queues, each output queue has a one-to-one correspondence with the port control devices and the buffering unit for storing the packets is linked to the output queue corresponding to the port control device at a target port; wherein each output port has a number of reserved buffering units which are not used by any other output port, and the source port triggers or terminates a congestion mode to control the number of free buffering units in response to the number of reserved buffering units in the output queue, and each port control device includes: a receive medium access control device coupled to one of the physical layer devices, wherein the received medium access control device inspects any incoming network packet for errors, if no errors is found, the packet is accepted, otherwise the packet is returned; a receive control device coupled to the receive medium access control device, the queue control device and the buffer control device, the receive control device issues requests to the buffer control device to assign at least one buffering units(s) for storing the packet and signals the queue control device to request queuing to the corresponding output queue; an output control device, coupled to the queue control device and the buffer control device for outputting the packet from the output queue, and releasing the buffering units after the buffer control unit has sent out the packet; a transmission medium access control device coupled to the output control device and one of the physical layer devices for outputting the packet to the physical layer device, and when the congestion control mode is triggered, the transmission medium access control device within the port control device that corresponds to the source port sends out a control signal to execute the congestion control operation; and a physical layer control device coupled to the transmission medium access control device and one of the physical layer devices, receiving a plurality of state signals from an external network device to select a proper congestion control mode.