Queue speed-up by using multiple linked lists

1. A switch, comprising:

a transmission module operable to determine corresponding output ports for frames stored in a queue; and

a queue management module operable to:

store frames associated with the queue in a number of sub-queues which allow frames in different sub-queues to be retrieved independently;

select a second sub-queue for retrieving a second frame before receiving a queue status update of a previously selected first sub-queue from which a first frame has been retrieved; and

schedule subsequent transmissions for the first and second frames before receiving a queue status update of the first sub-queue, thereby achieving a pipelined parallel processing among the sub-queues.

2. The switch of claim 1 , wherein the sub-queues are implemented using linked lists, wherein a respective linked list has a head and a tail pointer, and wherein the head and the tail pointers are maintained by the queue management circuitry.

3. The switch of claim 2 , further comprising a linked list management module operable to:

store a respective linked list corresponding to a respective sub-queue; and

update the head pointer maintained by the queue management circuitry.

4. The switch of claim 1 , wherein the queue management module further comprises a first counter associated with the queue, and wherein a current count of the first counter specifies in which sub-queue an incoming frame is to be enqueued.

5. The switch of claim 4 , wherein the queue management module is operable to queue the incoming frame to a sub-queue following a round-robin sequence.

6. The switch of claim 1 , wherein the queue management module further comprises a second counter associated with the queue, and wherein a current count of the second counter specifies from which sub-queue an outgoing frame is to be dequeued.

7. The switch of claim 6 , wherein the outgoing frame is dequeued from the sub-queues following a round-robin sequence; and

wherein the queue management module is further operable to increment the second counter to select the second sub-queue before receiving a queue status update of the first sub-queue.

8. The switch of claim 1 , wherein the sub-queues include at least one queue that is associated with an inactive output port.

9. The switch of claim 1 , wherein the switch is a Fibre Channel over Ethernet (FCoE) switch.

10. The switch of claim 1 , wherein the queue is associated with a priority class.

11. The switch of claim 1 , wherein the queue is a Fibre Channel (FC) virtual channel (VC) queue configured to store frames belonging to a particular VC.

12. A computer-executable method for facilitating queuing of communication frames at a switch, comprising:

storing frames associated with a queue in a number of sub-queues which allow frames in different sub-queues to be retrieved independently;

selecting a second sub-queue for retrieving a second frame before receiving a queue status update of a previously selected first sub-queue from which a first frame has been retrieved; and

scheduling subsequent transmissions for the first and second frames before receiving a queue status update of the first sub-queue, thereby achieving a pipelined parallel processing among the sub-queues.

13. The method of claim 12 , further comprising:

implementing the sub-queues using linked lists, wherein a respective linked list has a head and a tail pointer; and

maintaining the head and the tail pointers for the linked list in queue management circuitry.

14. The method of claim 13 , further comprising:

storing a respective linked list corresponding to a respective sub-queue in a linked-list management circuitry; and

updating, by the linked-list management circuitry, the head pointer maintained in the queue management circuitry after a frame is retrieved from the corresponding sub-queue.

15. The method of claim 12 , further comprising maintaining a first counter associated with the queue, wherein a current count of the first counter specifies in which sub-queue an incoming frame is to be enqueued.

16. The method of claim 15 , wherein the incoming frame is enqueued to a sub-queue following a round-robin sequence.

17. The method of claim 12 , further comprising maintaining a second counter associated with the queue, and wherein a current count of the second counter specifies from which sub-queue an outgoing frame is to be dequeued.

18. The method of claim 17 , wherein the outgoing frame is dequeued from the sub-queues following a round-robin sequence; and

further comprising incrementing the second counter to select the second sub-queue before receiving a queue status update of the first sub-queue.

19. The method of claim 12 , wherein storing the frames in the sub-queues involves storing at least one frame in a queue that is associated with an inactive output port.

20. The method of claim 12 , wherein the switch is a Fibre Channel over Ethernet (FCoE) switch.

21. The method of claim 12 , wherein the queue is associated with a priority class.

22. The method of claim 12 , wherein the queue is a Fibre Channel (FC) virtual channel (VC) queue configured to store frames belonging to a particular VC.

23. A queuing means, comprising:

a storing means for storing frames associated with a queue in a number of sub-queues which allow frames in different sub-queues to be retrieved independently;

a selecting means for selecting a second sub-queue for retrieving a second frame before receiving a queue status update of a previously selected first sub-queue from which a first frame has been retrieved; and

a scheduling means for scheduling subsequent transmissions for the first and second frames before receiving a queue status update of the first sub-queue, thereby achieving a pipelined parallel processing among the sub-queues.