Priority aware MAC flow control

• US 8,743,691 B2
• Filed: 06/15/2011
• Issued: 06/03/2014
• Est. Priority Date: 10/23/2003
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Foundry Networks LLC (Broadcom, Inc.)
• Inventors: Jain, Nitin, Jalan, Rajkumar
• Primary Examiner(s): Sheikh, Ayaz
• Assistant Examiner(s): HALIYUR, VENKATESH N
• Application Number:
  US13/161,439
• Publication Number:
  US 20120147747A1
• Time in Patent Office: 1,084 Days
• Field of Search: 370208-352
• US Class Current: 370/235
• CPC Class Codes: G06F 15/17368 non hierarchical topologies
• CPC Class Codes: H04L 12/2852 Metropolitan area networks
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/2433 Allocation of priorities to traffic types

Abstract

Solutions are provided that allow a network device to apply flow control on the MAC layer while taking into account the priority of the frame of traffic. This may be accomplished by generating a frame indicating that traffic flow should be paused, while utilizing a new opcode value, or alternatively by utilizing a new type/length value (possibly combined with a new opcode value). A receiving device may then examine the fields of the frame to determine whether it should use priority-based pausing, and then examine other fields to determine which priority-levels to pause and for how long. This allows for improved efficiency in flow control on the MAC layer.

Claims

1. A method comprising:

determining, in a network device, a present need to pause traffic flow to the network device, and if a present need to pause traffic flow to the network device is determined, placing in a first field in a frame, a value signifying that traffic flow to the network device should be paused or not paused according to its priority level, the traffic flow comprising one or more packets including a priority level, the priority level indicating a relative level of importance of timely delivery of the packet to the network device, the value further indicating that the pausing will be for a time indicated by a second field in the frame without regard for the priority level; and

placing in a priority mask field of the frame, a value signifying which priority levels should be paused.

2. The method of claim 1, wherein the frame is a PAUSE frame.

3. The method of claim 1, wherein the value signifying that traffic flow to the network device should be paused or not paused according to its priority level is a value not used by standard PAUSE frames in the first field.

4. The method of claim 1, further comprising creating the priority mask field before the placing.

5. The method of claim 1 wherein the first field comprises a type/length field.

6. A method comprising:

examining, in a network device, a value in a first field in a frame to determine if it signifies that the frame indicates that traffic flow to the network device should be paused and if it signifies that traffic flow to the network device should be paused or not paused according to its priority level, the traffic flow comprising one or more packets including a priority level, the priority level indicating a relative level of importance of timely delivery of the packet to the network device, the value further indicating that the pausing will be for a time indicated by a second field in the frame without regard for the priority level; and

pausing traffic flow to the network device with priority levels corresponding to levels signified by a value in a priority mask field in the frame if the value in the first field signified that traffic flow to a network device should be paused and that traffic flow to the network device should be paused or not paused according to its priority level.

7. The method of claim 6, wherein the frame is a PAUSE frame.

8. The method of claim 6, wherein the value signifying that traffic flow to the network device should be paused or not paused according to its priority level is a value not used by standard PAUSE frames in the first field.

9. The method of claim 6 wherein the first field comprises a type/length field.

10. An apparatus comprising:

one or more processors;

a memory having stored thereon instructions that, when executed by the one or more processors, causes the one or more processors to;

if a present need to pause traffic flow to a network device is determined, place in a first field in a frame, a value signifying that traffic flow to the network device should be paused or not paused according to its priority level, the traffic flow comprising one or more packets including a priority level, the priority level indicating a relative level of importance of timely delivery of the packet to the network device, the value further indicating that the pausing will be for a time indicated by a second field in the frame without regard for the priority level; and

place in a priority mask field in the frame, a value signifying which priority levels should be paused.

11. The apparatus of claim 10, wherein the frame is a PAUSE frame.

12. The apparatus of claim 10, wherein the value signifying that traffic flow to the network device should be paused or not paused according to its priority level is a value not used by standard PAUSE frames in the first field.

13. The apparatus of claim 10, wherein the one or more processors are further configured to create the priority mask field before the placing.

14. The apparatus of claim 10 wherein the first field comprises a type/length field.

15. An apparatus comprising:

one or more processors; and

a memory having stored thereon instructions that, when executed by the one or more processors, causes the one or more processors to;

examine a value in a first field in a frame to determine if it signifies that the frame indicates that traffic flow to a network device should be paused and if it signifies that traffic flow to the network device should be paused or not paused according to its priority level, the traffic flow comprising one or more packets including a priority level, the priority level indicating a relative level of importance of timely delivery of the packet to the network device, the value further indicating that the pausing will be for a time indicated by a second field in the frame without regard for the priority level; and

pause traffic flow to the network device with priority levels corresponding to levels signified by a value in a priority mask field in the frame if the value in the first field signified that traffic flow to a network device should be paused and that traffic flow to the network device should be paused or not paused according to its priority level.

16. The apparatus of claim 15, wherein the frame is a PAUSE frame.

17. The apparatus of claim 15, wherein the value signifying that traffic flow to the network device should be paused or not paused according to its priority level is a value not used by standard PAUSE frames in the first field.

18. The method of claim 15 wherein the first field comprises a type/length field.

19. An apparatus comprising:

means for determining a present need to pause traffic flow to a network device, and if a present need to pause traffic flow to a network device is determined, placing in a first field in a frame, a value signifying that traffic flow to the network device should be paused or not paused according to its priority level, the traffic flow comprising one or more packets including a priority level, the priority level indicating a relative level of importance of timely delivery of the packet to the network device, the value further indicating that the pausing will be for a time indicated by a second field in the frame without regard for the priority level; and

means for placing in a priority mask field of the frame, a value signifying which priority levels should be paused.

20. An apparatus comprising:

means for examining a value in a first field in a frame to determine if it signifies that the frame indicates that traffic flow to a network device should be paused and if it signifies that traffic flow to the network device should be paused or not paused according to its priority level, the traffic flow comprising one or more packets including a priority level, the priority level indicating a relative level of importance of timely delivery of the packet to the network device, the value further indicating that the pausing will be for a time indicated by a second field in the frame without regard for the priority level; and

means for pausing traffic flow to the network device with priority levels corresponding to levels signified by a value in a priority mask field in the frame if the value in the first field signified that traffic flow to the network device should be paused and that traffic flow to the network device should be paused or not paused according to its priority level.

21. A non-transitory computer readable storage medium having stored thereon program code executable by a network device, the program code comprising:

code that causes the network device to determine a present need to pause traffic flow to the network device, and if a present need to pause traffic flow to the network device is determined, code that causes the network device to place in a first field in a frame, a value signifying that traffic flow to the network device should be paused or not paused according to its priority level, the traffic flow comprising one or more packets including a priority level, the priority level indicating a relative level of importance of timely delivery of the packet to the network device, the value further indicating that the pausing will be for a time indicated by a second field in the frame without regard for the priority level;

code that causes the network device to place in a priority mask field of the frame, a value signifying which priority levels should be paused.

22. A non-transitory computer readable storage medium having stored thereon program code executable by a network device, the program code comprising:

code that causes the network device to examine a value in a first field in a frame to determine if it signifies that the frame indicates that traffic flow to the network device should be paused and if it signifies that traffic flow to the network device should be paused or not paused according to its priority level, the traffic flow comprising one or more packets, including a priority level, the priority level indicating a relative level of importance of timely delivery of the packet to the network device, the value further indicating that the pausing will be for a time indicated by a second field in the frame without regard for the priority level; and

code that causes the network device to pause traffic flow to the network device with priority levels corresponding to levels signified by a value in a priority mask field in the frame if the value in the first field signified that traffic flow to a network device should be paused and that traffic flow to the network device should be paused or not paused according to its priority level.