Speculative loading of buffers within a port of a network device

• US 6,920,106 B1
• Filed: 09/07/2001
• Issued: 07/19/2005
• Est. Priority Date: 09/07/2001
• Status: Expired due to Fees

• Current Assignee: Microsemi Storage Solutions (U.S.), Inc. (Microchip Technology Incorporated)
• Original Assignee: Agilent Technologies, Inc.
• Inventors: Cremel, Olivier, Chou, Norman
• Primary Examiner(s): HO, DUC CHI
• Application Number:
  US09/948,455
• Time in Patent Office: 1,411 Days
• Field of Search: 370/412, 370/229, 370/235, 370/429, 370/401, 370/315, 710/52, 710/305, 710/310, 709/318
• US Class Current: 370/229
• CPC Class Codes: H04L 41/046 comprising network management agents or mobile agents therefor
• CPC Class Codes: H04L 43/00 Arrangements for monitoring or testing data switching networks
• CPC Class Codes: H04L 49/3018 Input queuing
• CPC Class Codes: H04L 49/35 Switches specially adapted for specific applications
• CPC Class Codes: H04L 49/358 Infiniband Switches
• CPC Class Codes: H04L 49/555 Error detection

Abstract

In one embodiment a method for processing an incoming packet in a port of an interconnect device includes speculatively forwarding the incoming packet to multiple buffers within the port prior to determining which of the multiple buffers is a target buffer for the packet, decoding the packet, and determining which of the multiple buffers is the target buffer for the packet using the decoded packet. The method further includes notifying an agent associated with the target buffer that the target buffer is an intended owner of the data packet. In one embodiment, agents associated with the multiple buffers are designated to process packets that are not subject to a credit-based flow control method.

Claims

1. A method for processing an incoming packet in a port of an interconnect device, the method comprising:

speculatively forwarding the packet to a plurality of buffers within the port prior to determining which of the plurality of buffers is a target buffer for the packet;

decoding the packet;

determining which of the plurality of buffers is the target buffer for the packet using the decoded packet; and

notifying an agent associated with the target buffer that the target buffer is an intended owner of the packet.

2. The method of claim 1 wherein the port is a management port of the interconnect device.

3. The method of claim 1 wherein the notifying of the agent includes sending a signal indicating that the packet resides in the target buffer properly.

4. The method of claim 1 wherein agents associated with the plurality of buffers process packets that are not subject to a credit-based flow control method.

5. The method of claim 4 wherein the plurality of buffers are virtual lane 15 (VL 15) buffers.

6. The method of claim 5 wherein the agent associated with the target buffer is any one of a subnet management agent (SMA), an SMA passthrough agent, and a processor bus interface.

7. The method of claim 4 further comprising:

the agent blocking load of the target buffer until the packet is processed.

8. The method of claim 7 further comprising:

the agent ensuring that no partial loading of a next incoming packet can occur before unblocking the load.

9. The method of claim 1 further comprising:

notifying each agent associated with other buffers of the plurality of buffers other than the target buffer that the packet resides in the other buffers of the plurality of buffers improperly.

10. A method for processing an incoming packet in a port of an interconnect device, the method comprising:

speculatively forwarding the packet to each of a first group of buffers and an intermediary buffer associated with a second group of buffers prior to determining which buffer from the first group of buffers and the second group of buffers is a target buffer for the packet;

decoding the packet;

determining which buffer from the first group of buffers and the second group of buffers is the target buffer for the packet using the decoded packet; and

notifying an agent associated with the target buffer that the target buffer is an intended owner of the packet.

11. The method of claim 10 wherein the port is a management port of the interconnect device.

12. The method of claim 10 wherein:

agents associated with the first group of buffers process packets that are not subject to a credit-based flow control method;

agents associated with the second group of buffers process packets that are subject to a credit-based flow control method; and

the intermediary buffer is associated with a flow controller to manage credits for packets received by t he second group of buffers.

13. The method of claim 12 wherein the first group of buffers consists of virtual lane 15 (VL 15) buffers and the second group of buffers consists of non-VL 15 buffers.

14. The method of claim 13 wherein non-VL 15 buffers are VL 0 buffers.

15. The method of claim 14 wherein each agent associated with a buffer from the second group of buffers is any one of a performance management agent (PMA), a baseboard management agent (BMA), and a processor bus interface.

16. The method of claim 13 wherein each agent associated with a buffer from the first group of buffers is any one of a subnet manager agent (SMA), an SMA passthrough agent, and a processor bus interface.

17. The method of claim 10 wherein:

the target buffer is a buffer from the first group of buffers; and

notifying the agent includes sending a signal indicating that the packet resides in the target buffer properly.

18. The method of claim 17 further comprising:

notifying each agent associated with the remaining buffers from the first group of buffers that the packet resides in each of the remaining buffers improperly; and

notifying a flow controller associated with the intermediary buffer that the packet resides in the intermediary buffer improperly.

19. The method of claim 17 further comprising:

the agent blocking load of the target buffer until the packet is processed.

20. The method of claim 19 further comprising:

the agent ensuring that no partial loading of a next incoming packet can occur before unblocking the load.

21. The method of claim 10 wherein:

the target buffer is a buffer from the second group of buffers; and

notifying the agent further includes sending a signal indicating that the packet resides in the intermediary buffer properly to a flow controller associated with the intermediary buffer and to a target agent associated with the target buffer.

22. The method of claim 21 further comprising:

the target agent obtaining the packet from the intermediary buffer if a corresponding pending indicator is not set; and

the flow controller releasing the credit associated with the packet.

23. The method of claim 22 wherein the pending indicator is set while the intended agent processes a prior packet.

24. The method of claim 21 further comprising:

the target agent determining that a pending indicator is set and obtaining the packet from the intermediary buffer after processing of a prior packet is completed.

25. A method for processing an incoming packet in a port of an interconnect device, the method comprising:

speculatively forwarding the packet to each of a first group of buffers and to an intermediary buffer associated with a second group of buffers prior to decoding the packet;

decoding the packet;

based upon the decoded packet, notifying each agent associated with any one of the intermediary buffer, the first group of buffers and the second group of buffers whether the packet is valid and whether a corresponding buffer from the first group of buffers and the second group of buffers is a target buffer for the packet.

26. The method of claim 25 wherein the port is a management port of the interconnect device.

27. The method of claim 25 wherein:

agents associated with the first group of buffers process packets that are not subject to a credit-based flow control method;

agents associated with the second group of buffers process packets that are subject to the credit-based flow control method; and

the intermediary buffer is associated with a flow controller to manage credits for packets received by the second group of buffers.

28. The method of claim 27 wherein the first group of buffers consists of virtual lane 15 (VL 15) buffers and the second group of buffers consists of non-VL 15 buffers.

29. The method of claim 27 further comprising:

the flow controller releasing credit associated with the packet upon receiving a notification that the packet is invalid and that the target buffer is from the second group of buffers.

30. An apparatus for processing an incoming packet in a port of an interconnect device, the apparatus comprising:

means to speculatively load the packet to each of the first group of buffers when the packet is received at the port;

means to decode the packet;

means to determine which of the first group of buffers is a target buffer for the packet; and

means to notify an agent associated with the target buffer that the target buffer is an intended owner of the packet.

31. An apparatus for processing an incoming packet in a port of an interconnect device, the apparatus comprising:

a first group of buffers to store the packet speculatively loaded to each of the first group of buffers when the packet is received at the port;

a first set of agents associated with the first group of buffers to control operations pertaining to the packet; and

a decoder to decode the packet, to determine which of the first group of buffers is a target buffer for the packet, and to notify an agent associated with the target buffer that the target buffer is an intended owner of the packet.

32. The apparatus of claim 31 further comprising:

an intermediary buffer to store the packet speculatively loaded to the intermediary buffer when the packet is received at the port;

a second group of buffers associated with the intermediary buffer, one of the second group of buffers is to receive the packet from the intermediary buffer if said one of the second group of buffers is the target buffer.

33. The apparatus of claim 32 further comprising:

a second set of agents, associated with the second group of buffers, to process packets that are subject to a credit-based flow control method; and

a flow controller, associated with the intermediary buffer, to manage credits for packets received by the second group of buffers.

34. The apparatus of claim 33 wherein the first group of buffers consists of virtual lane 15 (VL 15) buffers and the second group of buffers consists of non-VL 15 buffers.

35. The apparatus of claim 34 wherein non-VL 15 buffers are VL 0 buffers.

36. The apparatus of claim 35 wherein each agent associated with a buffer from the second group of buffers is any one of a performance management agent (PMA), a baseboard management agent (BMA), and a processor bus interface.

37. The apparatus of claim 34 wherein each agent associated with a buffer from the first group of buffers is any one of a subnet manager agent (SMA), an SMA passthrough agent, and a processor bus interface.

38. The apparatus of claim 31 wherein the port is a management port of the interconnect device.

39. The apparatus of claim 31 wherein packets processed by the first set of agents are not subject to a credit-based flow control method.

40. The apparatus of claim 31 wherein:

the target buffer is a buffer from the first group of buffers; and

the decoder is to notify the agent by sending a signal indicating that the packet resides in the target buffer properly.

41. The apparatus of claim 40 wherein the decoder is to further notifying each agent associated with the remaining buffers from the first group of buffers that the packet resides in each of the remaining buffers improperly, and to notify a flow controller associated with the intermediary buffer that the packet resides in the intermediary buffer improperly.

42. The apparatus of claim 40 wherein the agent is to block load of the target buffer until the packet is processed.

43. The apparatus of claim 42 wherein the agent is to ensure that no partial loading of a next incoming packet can occur before unblocking the load.

44. The apparatus of claim 31 wherein:

the target buffer is a buffer from the second group of buffers; and

the decoder is to send a signal indicating that the packet resides in the intermediary buffer properly to a flow controller associated with the intermediary buffer and to a target agent associated with the target buffer.

45. The apparatus of claim 44 wherein the target agent is to obtain the packet from the intermediary buffer if a corresponding pending indicator is not set, and the flow controller is to release the credit associated with the packet.

46. The apparatus of claim 45 wherein the target agent is to set the pending indicator when receiving an indicator of ownership pertaining to a next packet while processing the current packet.

47. The apparatus of claim 44 wherein the target agent is to determine that a pending indicator is set and to obtain the packet from the intermediary buffer after processing of a prior packet is completed.

48. A machine-readable medium storing a description of a circuit, said circuit comprising:

a grant controller to speculatively forward a packet received at a port of an interconnect device to a plurality of buffers within the port prior to determining which of the plurality of buffers is a target buffer for the packet;

a decoder to decode the packet;

a parser to determine which of the plurality of buffers is the target buffer for the packet using the decoded packet; and

a notifier to notify an agent associated with the target buffer that the target buffer is an intended owner of the packet.

49. A machine-readable medium storing a description of a circuit, said circuit comprising:

a grant controller to speculatively forward a packet received at a port of an interconnect device to each of a first group of buffers and an intermediary buffer associated with a second group of buffers prior to determining which buffer from the first group of buffers and the second group of buffers is a target buffer for the packet;

a decoder to decode the packet;

a parser to determine which buffer from the first group of buffers and the second group of buffers is the target buffer for the packet using the decoded packet; and

a notifier to notify an agent associated with the target buffer that the target buffer is an intended owner of the packet.

50. A machine-readable medium storing a description of a circuit, said circuit comprising:

a grant controller to speculatively forward a packet received at a port of an interconnect device to each of a first group of buffers and to an intermediary buffer associated with a second group of buffers prior to decoding the packet;

a decoder to decode the incoming packet; and

a notifier to notify each agent associated with any one of the intermediary buffer, the first group of buffers and the second group of buffers whether the packet is valid and whether a corresponding buffer from the first group of buffers and the second group of buffers is a target buffer for the packet.