System and method of maintaining coherent and synchronized address tables on all switches in a software stacking configuration

• US 20040062257A1
• Filed: 09/30/2002
• Published: 04/01/2004
• Est. Priority Date: 09/30/2002
• Status: Abandoned Application

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Nguyen, Tuan Anh
• Application Number:
  US10/259,902
• Publication Number:
  US 20040062257A1
• Time in Patent Office: Days
• US Class Current: 370/403
• CPC Class Codes: H04L 41/0213 Standardised network management protocols, e.g. simple network management protocol [SNMP]

Abstract

Methods and systems provide for identical address tables in a software stack of switches. The software stack is maintained by organizing the switches into the software stack. Each switch in the software has a corresponding address table and one or more ports. Each address table maps one or more packet addresses to a port in the software stack. Synchronization of the address tables is initiated and enables significant performance improvements. Synchronization is initiated by populating a command buffer of a first switch in the stack with one or more address table commands. The buffer is distributed to remaining switches in the stack.

Claims

1. A method of maintaining a software stack of switches, the method comprising:

organizing the switches into a software stack, each switch in the software stack having a corresponding address table and one or more ports, each address table mapping one or more packet addresses to a port in the software stack; and

initiating synchronization of the address tables.

2. The method of claim 1 further including:

populating a command buffer of a first switch in the stack with one or more address table commands; and

distributing the buffer to remaining switches in the stack.

3. The method of claim 2 further including:

confirming execution of the commands by the remaining switches; and

passing a synchronization token to a next switch in the stack, the synchronization token to enable the next switch to initiate synchronization of the address tables.

4. The method of claim 3 further including re-distributing the buffer if one or more of the commands are not executed by one or more of the remaining switches.

5. The method of claim 2 further including:

determining whether the buffer is full; and

distributing the buffer if the buffer is full.

6. The method of claim 2 further including:

determining whether a predetermined period of time has expired since the buffer was last distributed to the remaining switches; and

distributing the buffer if the predetermined period of time has expired.

7. The method of claim 2 further including:

encountering a new address at a port of the first switch; and

writing an add command to the command buffer based on the new address.

8. The method of claim 2 further including:

identifying a stale address assigned to a port of the first switch; and

writing a delete command to the command buffer based on the stale address.

9. The method of claim 8 further including dynamically aging the stale address.

10. The method of claim 2 further including:

identifying a relocated address, the relocated address being assigned to a first port of the first switch and located at a second port of the first switch; and

writing a move command to the command buffer based on the relocated address.

11. The method of claim 1 wherein the switches are application specific integrated circuits (ASICs).

12. The method of claim 1 wherein the switches are physically connected through an Ethernet medium.

13. The method of claim 1 further including organizing switches having a daisy-chain topology.

14. The method of claim 1 further including organizing switches having a star topology.

15. The method of claim 1 further including organizing switches having a ring topology.

16. The method of claim 1 further including:

assigning each switch a device identifier; and

assigning a stack priority to each device identifier.

17. A method of initiating synchronization of a plurality of address tables, each address table corresponding to a switch in a software stack, the method comprising:

populating a command buffer of a first switch in the software stack with one or more address table commands;

receiving a synchronization token; and

distributing the buffer to remaining switches in the software stack in response to receiving the synchronization token.

18. The method of claim 17 further including:

confirming execution of the commands by the remaining switches; and

passing the synchronization token to a next switch in the software stack.

19. The method of claim 18 further including re-distributing the buffer if one or more of the commands are not executed by one or more of the remaining switches.

20. The method of claim 17 further including:

determining whether the buffer is full; and

distributing the buffer if the buffer is full.

21. The method of claim 17 further including:

determining whether a predetermined period of time has expired since the buffer was last distributed to the remaining switches; and

distributing the buffer if the predetermined period of time has expired.

22. A method of processing an address table command buffer, the method comprising:

receiving the buffer;

parsing one or more commands from the buffer; and

executing the commands, execution of the commands to enable an address table of a responding switch to be synchronized with an address table of an initiating switch.

23. The method of claim 22 wherein the switches are part of a software stack, each switch having one or more ports, each address table mapping one or more packet addresses to a port in the software stack.

24. The method of claim 22 further including transmitting results of the execution to the initiating switch.

25. A method of maintaining a software stack of application specific integrated circuits (ASICs), the method comprising:

organizing the ASICs into a software stack by assigning each ASIC a device identifier and assigning a stack priority to each device identifier, each ASIC in the software stack having a corresponding address table and one or more ports, each address table mapping one or more packet addresses to a port in the software stack;

populating a remote procedure call (RPC) command buffer of a first ASIC in the stack with one or more address table commands;

distributing the buffer to remaining ASICs in the stack;

confirming execution of the commands by the remaining ASICs;

re-distributing the buffer if one or more of the commands are not executed by one or more of the remaining switches; and

passing a synchronization token to a next ASIC in the stack, the synchronization token to enable the next ASIC to initiate synchronization of the address tables.

26. The method of claim 25 further including:

determining whether the buffer is full; and

distributing the buffer if the buffer is full.

27. The method of claim 25 further including:

determining whether a predetermined period has expired since the buffer was last distributed; and

distributing the buffer if the predetermined period of time has expired.

28. A machine readable medium storing a set of instructions capable of being executed by a processor to:

populate a command buffer of a first switch in the software stack with one or more address table commands;

receive a synchronization token; and

distribute the buffer to remaining switches in the software stack in response to receiving the synchronization token.

29. The medium of claim 28 wherein the instructions are further capable of being executed by a processor to:

confirm execution of the commands by the remaining switches; and

pass the synchronization token to a next switch in the software stack.