Pipelined packet processor

• US 20050226242A1
• Filed: 04/28/2004
• Published: 10/13/2005
• Est. Priority Date: 03/30/2004
• Status: Active Grant

• Current Assignee: Extreme Networks, Inc.
• Original Assignee: Extreme Networks, Inc.
• Inventors: Parker, David K.
• Granted Patent: US 7,649,879 B2
• Time in Patent Office: Days
• US Class Current: 370/389
• CPC Class Codes: H04L 12/56 Packet switching systems
• CPC Class Codes: H04L 45/7453 using hashing
• CPC Class Codes: H04L 47/2441 relying on flow classification, e.g. using integrated services [IntServ]

Abstract

A pipelined packet processor is described having at least one pipeline, the at least one pipeline having one or more processing slots. Packets are assigned to available ones of the slots, and each of one or more of the assigned packets are processed during one or more cycles of processing. Upon or after a packet has undergone one or more cycles of processing, a packet classification or filtering decision is derived for the packet.

Claims

1. A pipelined packet processing system comprising:

a pipelined processor configured to

     1) provide at least one pipeline having one or more slots,

     2) assign packets to each of one or more available ones of the slots,

     3) process one or more of the assigned packets during one or more cycles of processing, and

     4) derive a packet classification or forwarding decision for each of one or more of the assigned packets, upon or after the packet has undergone one or more cycles of processing.

2. The system of claim 1 wherein the pipelined processor is further configured to process a packet associated with a slot during a processing cycle by 1) accessing one or more resources responsive to packet processing state data relating to the packet, 2) retrieving data from the one or more resources, and 3) selectively updating the packet processing state data relating to the packet responsive to the data retrieved from the one or more resources.

3. The system of claim 1 wherein the assigned packets are processed in sequence during a cycle of processing.

4. The system of claim 1 wherein each of the assigned packets undergoes a common, predetermined number of processing cycles.

5. The system of claim 1 wherein the processor is configured to fill one or more available ones of the slots with packet processing state data during a loading mode of operation, and process the packets assigned to the available slots during a subsequent processing mode of operation that commences after the loading mode of operation.

6. The system of claim 1 wherein the processor is configured to assign packets to available ones of the slots as obtained from a queue.

7. The system of claim 6 wherein the processor is configured to bypass available ones of the slots if and while the queue is empty.

8. The system of claim 6 wherein packet identifiers, identifying packets as stored in a buffer, are stored in the queue.

9. The system of claim 1 wherein packet processing state data relating to a packet is stored in a slot of the pipeline assigned to a packet.

10. The system of claim 9 wherein the packet processing state data as stored in a slot of the pipeline is an identifier of packet processing state data as stored in a buffer.

11. The system of claim 1 wherein the packet processing state data comprises control data.

12. The system of claim 11 wherein the packet processing state data comprises pipeline management information.

13. The system of claim 11 wherein the packet processing state data comprises static packet information.

14. The system of claim 1 wherein the packet processing state data comprises packet classification or forwarding data.

15. The system of claim 14 wherein the packet processing state data comprises priority-based packet classification or forwarding data.

16. The system of claim 13 wherein the packet processing state data comprises non-priority-based packet or forwarding data.

17. The system of claim 16 wherein the non-priority-based packet or forwarding data comprises one or more sticky flags.

18. The system of claim 1 wherein the packet processing state data comprises statistical information relating to the packet.

19. The system of claim 18 wherein the statistical information relates to each of a plurality of the processing cycles performed on the corresponding packet data.

20. The system of claim 1 wherein the packet processor is further configured to release an assigned slot after processing of the corresponding packet has been completed.

21. The system of claim 1 wherein the packet processor is configured to release a slot by unloading packet processing state data relating to the packet from the slot.

22. A method of performing pipelined processing of one or more packets comprising the steps of:

providing at least one pipeline having one or more slots;

assigning packets to each of one or more available ones of the slots;

processing each of one or more of the assigned packets during one or more cycles of processing; and

deriving a classification or forwarding decision for each of one or more of the assigned packets after each has undergone or more cycles of processing.

23. The method of claim 22 wherein the processing step further comprises processing each of one or more assigned packets in sequence during a cycle of processing.

24. The method of claim 22 wherein the processing step further comprises processing each of one or more assigned ones of the packets for a common, predetermined number of processing cycles.

25. The method of claim 22 wherein the number of slots is a predetermined, programmed variable.

26. The method of claim 22 wherein the step of assigning a packet to a slot comprises storing packet processing state data relating to the packet in the slot.

27. The method of claim 22 further comprising releasing an assigned slot upon or after processing of the corresponding packet has been completed.

28. The method of claim 27 wherein the step of releasing a slot comprises unloading packet processing state data from the slot.

29. The method of claim 22 further comprising assigning packets to available slots as obtained from a queue.

30. The method of claim 29 further comprising bypassing available ones of the slots if and while the queue is empty.

31. The method of claim 22 further comprising assigning a packet to a slot by storing an identifier of the packet as stored in a buffer in the slot.

32. The method of claim 26 wherein the packet processing state data stored in a slot comprises an identifier of the packet as stored in a buffer.

33. The method of claim 26 wherein the packet processing state data stored in a slot comprises control data.

34. The method of claim 33 wherein the control data comprises pipeline management data.

35. The method of claim 33 wherein the control data comprises static packet information.

36. The method of claim 22 wherein the packet processing state data comprises packet classification or forwarding data.

37. The method of claim 22 wherein the packet processing state data comprises priority-based packet classification or forwarding data.

38. The method of claim 22 wherein the packet processing state data comprises non-priority-based packet classification or forwarding data.

39. The method of claim 38 wherein the packet processing state data comprises one or more sticky flags relating to the packet.

40. The method of claim 22 wherein the packet processing state data comprises statistical data relating to the packet.

41. The method of claim 40 wherein the statistical data relates to each of a plurality of processing cycles performed on the corresponding packet data.

42. The method of claim 22 wherein the step of processing a packet assigned to a slot during a cycle of processing comprises the sub-steps of:

accessing one or more resources responsive to packet processing state data corresponding to the packet data stored in the slot;

retrieving data from the one or more resources; and

selectively updating the packet processing state data corresponding to the packet responsive to data retrieved from the one or more resources.

43. A system for performing pipelined processing of one or more packets comprising:

first means for providing at least one pipeline having one or more slots;

second means for assigning packets to one or more available ones of the slots, processing each of one or more of the assigned packets during one or more cycles of processing; and

third means for deriving classification or forwarding decision for a packet upon or after the same has undergone one or more cycles of processing.