Queue processing method

Abstract

A method of processing data packets, each data packet being associated with one of a plurality of entities. The method comprises storing a data packet associated with a respective one of said plurality of entities in a buffer, storing state parameter data associated with said stored data packet, the state parameter data being based upon a value of a state parameter associated with said respective one of said plurality of entities, and processing a data packet in said buffer based upon said associated state parameter data.

What is claimed is: 
     
         1 . An apparatus, comprising:
 a plurality of output ports, each output port of the plurality of output ports having an associated state parameter counter, wherein the state parameter counter is configured to be indicative of an operational state of a device connected to that port; and   a shared queue configured to store packets received on a plurality of input ports with an entry in the shared queue including both the packets received and a value of the state parameter associated with the output port on which the packet is to be directed at the time the packet was received;   wherein a state parameter counter associated with a port is updated based on detection of an event associated with the device connected to that port; and   wherein a packet at the head of the shared queue is processed based on a comparison of the state parameter value stored in the shared queue with the packet and a current value of the state parameter counter of the output port on which the packet is to be transmitted.   
     
     
         2 . The apparatus of  claim 1 , wherein the packet at head of the shared queue is forwarded to an output port of the plurality of output ports based on the state parameter value stored in the shared queue with the packet matching the current value of the state parameter counter of the output port on which the packet is to be transmitted. 
     
     
         3 . The apparatus of  claim 1 , wherein the packet at head of the shared queue is discarded based on the state parameter value stored in the shared queue with the packet not matching the current value of the state parameter counter of the output port on which the packet is to be transmitted. 
     
     
         4 . The apparatus of  claim 1 , wherein the state parameter counter associated with a port is updated based on the event indicating the device connected to that port has been reset. 
     
     
         5 . The apparatus of  claim 4 , wherein the state parameter counter associated with a port is incremented based on the event indicating the device connected to that port has been reset. 
     
     
         6 . The apparatus of  claim 1 , wherein the state parameter counter associated with a port remains at a current value until a message is received from the device connected to that port. 
     
     
         7 . The apparatus of  claim 1 , wherein each of the plurality of input ports has an associated state parameter counter that may also be updated based on a message received from a peripheral device connected to an input port of the plurality of input ports. 
     
     
         8 . A method, comprising:
 receiving a packet at an input port of a switch, the packet designating an output port;   storing the packet in a shared queue along with a value of a state parameter counter associated with the output port;   detecting an event at a device connected to the output port;   updating the state parameter counter associated with the output port based on the event; and   processing the first packet based on the stored value of the state parameter counter.   
     
     
         9 . The method of  claim 8 , wherein the event causes the state parameter counter to increment. 
     
     
         10 . The method of  claim 8 , wherein processing the packet based on the stored value of the state parameter comprises:
 comparing the stored value of the state parameter counter with a current value of the state parameter counter; and   based on the stored value of the state parameter counter equaling the current value of the state parameter counter, forwarding the packet to the output port.   
     
     
         11 . The method of  claim 8 , wherein processing the packet based on the stored value of the state parameter comprises:
 comparing the stored value of the state parameter counter with a current value of the state parameter counter; and   based on the stored value of the state parameter counter being unequal to the current value of the state parameter counter, discarding the packet to the output port.   
     
     
         12 . The method of  claim 8 ,
 receiving an additional packet at the input port of the switch, the packet designating a second output port;   storing the additional packet in the shared queue along with a value of a second state parameter counter associated with the second output port; and   processing the additional packet based on the stored value of the second state parameter.   
     
     
         13 . The method of  claim 8 , wherein the detected event indicates the device connected to the output port has been reset. 
     
     
         14 . An apparatus, comprising:
 a plurality of input/output ports with each input/output port of the plurality of input/output ports having an associated state parameter counter;   a buffer to store packets received on the plurality of input/output ports and configured to:
 store a value of the state parameter counter with a received packet, the value representing the value of the state parameter counter at the time the packet arrived; and 
 selectively forward a packet at the head of the buffer to a destination based on a comparison of the stored value and a current value of the state parameter counter; and 
   wherein the state parameter value may be changed in response to a message received from a device connected to an input/output port of the plurality of input/output ports.   
     
     
         15 . The apparatus of  claim 14 , wherein the state parameter value is indicative of a state of operation of the device connected to that port. 
     
     
         16 . The apparatus of  claim 14 , wherein the packet is selectively forwarded based on the stored value and the current value of the state parameter counter being equal. 
     
     
         17 . The apparatus of  claim 14 , wherein the packet is discarded based on the stored value and the current value of the state parameter counter not being equal. 
     
     
         18 . The apparatus of  claim 17 , wherein the current value of the state parameter counter is greater than the stored value. 
     
     
         19 . The apparatus of  claim 14 , wherein the message indicates, at least, that the device connected to that port has been reset. 
     
     
         20 . The apparatus of  claim 14 , wherein the state parameter counter associated with an input/output port of the plurality of input/output ports is incremented in response to receiving a reset message from the device connected to that input/output port of the plurality of input/output ports.