Techniques to manage flow control

• US 20060126512A1
• Filed: 12/10/2004
• Published: 06/15/2006
• Est. Priority Date: 12/10/2004
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Rosenbluth, Mark B., Wolrich, Gilbert, Jain, Sanjeev, Wilkinson, Hugh M.
• Granted Patent: US 7,554,908 B2
• Time in Patent Office: Days
• US Class Current: 370/236
• CPC Class Codes: H04L 2012/5678 Traffic aspects, e.g. arbitration, load balancing, smoothing, buffer management
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 49/15 Interconnection of switching modules
• CPC Class Codes: H04L 49/254 Centralised controller, i.e. arbitration or scheduling
• CPC Class Codes: H04L 49/30 Peripheral units, e.g. input or output ports

Abstract

Method and apparatus to manage flow control for a network device are described.

Claims

1. An apparatus, comprising:

a first processor to include a transmit manager module and a transmit buffer module, said transmit manager module to send flow control messages to said transmit buffer module over a control path and a transmit path, and said transmit buffer module to manage flow control for a queue in response to said flow control messages.

2. The apparatus of claim 1, wherein said transmit manager module includes a flow control decoder and a transmit management flow control state machine.

3. The apparatus of claim 1, wherein said transmit buffer module includes a flow control table lookup and a transmit buffer flow control state machine.

4. The apparatus of claim 1, including a flow control service module to connect to said transmit buffer module, said transmit buffer module to send a request to perform roll back operations to said flow control service module.

5. The apparatus of claim 4, including a queue manager to connect to said flow control service module, said flow control service module to send said request to perform roll back operations to said queue manager, said request to include a segment descriptor, and said queue manager to write a remaining segment count using said segment descriptor.

6. The apparatus of claim 1, including a buffer and block manager to connect to said transmit buffer module, said buffer and block manager to receive a release message from said transmit buffer module, said buffer and block manager to release a buffer when said buffer is empty, and to release a block when a last buffer has been released.

7. The apparatus of claim 1, including:

a flow control bus to connect to said first processor;

a second processor to connect to said flow control bus; and

wherein said first processor is arranged to process packets from a network to a switch fabric, and said second processor is arranged to process packets from said switch fabric to said network.

8. The apparatus of claim 1, wherein said first processor comprises an ingress processor, said second processor comprises an egress processor, and at least one of said first and second processors is implemented using a network processor.

16. The system of claim 1, wherein said first processor comprises an ingress processor, said second processor comprises an egress processor, and at least one of said first and second processors is implemented using a network processor.

9. A system, comprising:

a switch fabric;

a first processor to connect to said switch fabric by a first bus;

a second processor to connect to said switch fabric by a second bus;

a flow control bus to connect said first processor and said second processor; and

wherein said first processor is to include a transmit manager module and a transmit buffer module, said transmit manager module to send flow control messages to said transmit buffer module over a control path and a transmit path, and said transmit buffer module to manage flow control for a queue in response to said flow control messages.

10. The system of claim 9, further comprising a communications medium to connect a network to said first processor and said second processor.

11. The system of claim 9, wherein said transmit manager module includes a flow control decoder and a transmit management flow control state machine.

12. The system of claim 9, wherein said transmit buffer module includes a flow control table lookup and a transmit buffer flow control state machine.

13. The system of claim 9, including a flow control service module to connect to said transmit buffer module, said transmit buffer module to send a request to perform roll back operations to said flow control service module.

14. The system of claim 13, including a queue manager to connect to said flow control service module, said flow control service module to send said request to perform roll back operations to said queue manager, said request to include a segment descriptor, and said queue manager to write a remaining segment count using said segment descriptor.

15. The system of claim 9, including a buffer and block manager to connect to said transmit buffer module, said buffer and block manager to receive a release message from said transmit buffer module, said buffer and block manager to release a buffer when said buffer is empty, and to release a block when a last buffer has been released.

17. A method, comprising:

receiving a first control message;

sending a second control message to turn off a queue over a control path;

sending a third control message over a transmit path to ensure all packets in said transmit path have arrived at said queue; and

changing a state for a first state table to indicate said queue has been turned off.

18. The method of claim 17, including:

receiving a fourth control message to indicate a set of roll back operations have been completed; and

changing said state for said first state table to indicate said roll back operations have been completed.

19. The method of claim 17, including:

receiving a fifth control message to turn on said queue; and

changing said state for said first state table to indicate said queue has been turned on.

20. The method of claim 17, including:

receiving said second control message;

turning off said queue; and

changing a state for a second state table to indicate said queue has been turned off.

21. The method of claim 17, including:

receiving said third control message before a packet; and

changing a state for a second state table to a normal operating state.

22. The method of claim 17, including:

receiving a packet before said third control message;

sending a sixth control message to perform roll back operations; and

changing a state for a second state table to wait for said third control message.

23. An article comprising a medium storing instructions that when executed by a processor are operable to receive a first control message, send a second control message to turn off a queue over a control path, send a third control message over a transmit path to ensure all packets in said transmit path have arrived at said queue, and change a state for a first state table to indicate said queue has been turned off.

24. The article of claim 23 further storing instructions that when executed by a processor are operable to receive a fourth control message to indicate a set of roll back operations have been completed, and change said state for said first state table to indicate said roll back operations have been completed.

25. The article of claim 23 further storing instructions that when executed by a processor are operable to receive a fifth control message to turn on said queue, and change said state for said first state table to indicate said queue has been turned on.

26. The article of claim 23 further storing instructions that when executed by a processor are operable to receive said second control message, turn off said queue, and change a state for a second state table to indicate said queue has been turned off.

27. The article of claim 23 further storing instructions that when executed by a processor are operable to receive said third control message before a packet, and change a state for a second state table to a normal operating state.

28. The article of claim 23 further storing instructions that when executed by a processor are operable to receive a packet before said third control message, send a sixth control message to perform roll back operations, and change a state for a second state table to wait for said third control message.