Enhancement to loop healing for malconfigured bus prevention

• US 7,457,302 B1
• Filed: 12/31/2002
• Issued: 11/25/2008
• Est. Priority Date: 12/31/2002
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Whitby-Strevens, Colin
• Primary Examiner(s): Vu; Thong H
• Application Number:
  US10/335,974
• Time in Patent Office: 2,156 Days
• Field of Search: 370/216, 370/276, 370/404, 370/229, 370/235, 370/462, 370/468, 370/231, 370/228, 709/227, 709/206, 709/225, 710/104, 710/107, 707/104, 707/203, 718/104, 726/26
• US Class Current: 370/404
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 45/18 Loop-free operations
• CPC Class Codes: H04L 49/353 Support for fire wire switches, i.e. according to IEEE 1394

Abstract

A method for safely adding nodes to a network provides safeguards to prevent adding nodes beyond a maximum number of nodes allowed in the network. In one aspect, if the node to be added exceeds the maximum number of nodes allowed, the connection between the node to be added and the network is quarantined. If the node to be added does not exceed the maximum number of nodes allowed, the connection is confirmed. In another aspect, an additional test is made to determine if the connection between the network and the node to be added creates a loop within the network. In the case of a detected loop, the connection between the network and the node to be added is quarantined. If the connection does not create a loop, it is confirmed.

Claims

1. A method of configuring a network having a plurality of nodes connected by a bus, the method comprising:

determining an existing number of member nodes on the network;

determining whether the existing number of member nodes plus a candidate node is less than a maximum number of nodes allowed in the network; and

quarantining a connection between the network and the candidate node if adding the candidate node to the network results in a number of nodes that exceeds the maximum number of nodes on the network.

2. The method of claim 1, wherein quarantining comprises deactivating a port on a PHY to which a connection is made.

3. The method of claim 1, further comprising confirming the connection if the candidate node, when added to the existing number of member nodes, does not exceed the maximum number of nodes allowed on the network.

4. The method of claim 1, further comprising performing a loop test on the connection between the network and the candidate node.

5. The method of claim 4, further comprising quarantining the connection between the network and the candidate node if adding the candidate node to the network creates a loop.

6. The method of claim 4, further comprising confirming the connection to the candidate node if adding the candidate node to the network does not create a loop.

7. A computer readable medium comprising instructions, which, when executed by a processor, configure a network having a plurality of nodes connected by a bus, by:

determining an existing number of member nodes on the network;

determining whether the existing number of member nodes plus a candidate node is less than a maximum number of nodes allowed in the network, wherein the maximum number of nodes allowed in the network is determined at least in part by the number of links in the network; and

quarantining a connection between the network and the candidate node if adding the candidate node to the network results in a number of nodes that exceeds the maximum number of nodes on the network.

8. The computer readable medium of claim 7, further comprising instructions, which, when executed by a processor, deactivate a port on a PHY to which a connection is made.

9. The computer readable medium of claim 7, further comprising instructions, which, when executed by a processor, confirm the connection if the candidate node, when added to the existing number of member nodes, does not exceed the maximum number of nodes allowed on the network.

10. The computer readable medium of claim 7, further comprising instructions, which, when executed by a processor, perform a loop test on the connection between the network and the candidate node.

11. The computer readable medium of claim 10, further comprising instructions, which, when executed by a processor, quarantines the connection between the network and the candidate node if adding the candidate node to the network creates a loop.

12. The computer readable medium of claim 7, further comprising instructions, which, when executed by a processor, confirm the connection to the candidate node if adding the candidate node to the network does not create a loop.

13. A system of nodes connected by a bus, comprising functionality for:

determining an existing number of member nodes on a network;

determining whether the existing number of member nodes plus a candidate node is less than a maximum number of nodes allowed in the network, wherein the maximum number of nodes allowed in the network is determined at least in part by the number of links in a combined network comprising the network and the candidate node; and

quarantining a connection between the network and the candidate node if adding the candidate node to the network results in a number of nodes that exceeds the maximum number of nodes on the network.

14. The system of claim 13, wherein the quarantining functionality comprises deactivating a port on a PHY to which a connection is made.

15. The system of claim 13, further comprising functionality for confirming the connection if the candidate node, when added to the existing number of member nodes, does not exceed the maximum number of nodes allowed on the network.

16. The system of claim 13, further comprising functionality for performing a loop test on the connection between the network and the candidate node.

17. The system of claim 16, further comprising functionality for quarantining the connection between the network and the candidate node if adding the candidate node to the network creates a loop.

18. The system of claim 16, further comprising functionality for confirming the connection to the candidate node if adding the candidate node to the network does not create a loop.

19. A method comprising:

determining an existing number of member nodes on a network;

comparing the existing number of member nodes plus a candidate node to the number of links that would exist in the network if the candidate node is added to the network; and

quarantining at least one connection between the network and the candidate node if the existing number of member nodes plus a candidate node is less than or equal to the number of links that would exist in the network if the candidate node is added to the network.

20. The method of claim 19, wherein quarantining comprises deactivating a port on a PHY to which a connection is made.

21. The method of claim 19, further comprising performing a loop test on the connection between the network and the candidate node.

22. The method of claim 19, further comprising quarantining the connection between the network and the candidate node if adding the candidate node to the network creates a loop.

23. The method of claim 19, further comprising confirming the connection to the candidate node if adding the candidate node to the network does not create a loop.

24. A method comprising:

determining whether adding a candidate node to a network creates one or more loops in said network; and

quarantining one or more connections between the network and the candidate node if it is determined that adding the candidate node to the network creates one or more loops.

25. The method of claim 24, wherein quarantining comprises deactivating a port on a PHY to which a connection is made.

26. The method of claim 24, further comprising confirming the connection to the candidate node if adding the candidate node to the network does not create a loop.

27. For use in a data network, a method comprising:

determining a number of existing nodes associated with said network;

evaluating the number of existing nodes plus a candidate node, and a number of links that would exist in the network if the candidate node is added to the network; and

quarantining at least one connection between the network and the candidate node if the existing number of nodes plus a candidate node is less than or equal to the number of links.

28. Network apparatus, comprising:

a first module adapted to determine whether adding a candidate node to a network creates one or more loops in said network; and

a second module adapted to quarantine one or more connections between the network and the candidate node if it is determined that adding the candidate node to the network creates one or more loops.

29. The apparatus of claim 28, wherein the second module is adapted to quarantine said one or more connections by deactivating a port on a PHY to which a connection is made.

30. The apparatus of claim 28, further comprising a third module adapted to confirm the connection to the candidate node if adding the candidate node to the network does not create a loop.