Disjoint multi-pathing for a data center network

• US 9,178,943 B2
• Filed: 05/30/2012
• Issued: 11/03/2015
• Est. Priority Date: 02/28/2012
• Status: Active Grant

• Current Assignee: Kyndryl Incorporated
• Original Assignee: International Business Machines Corporation
• Inventors: DeCusatis, Casimer M., Kamble, Keshav G., Kumbhare, Abhijit P., Recio, Renato J., Singh, Simarbir
• Primary Examiner(s): CATTUNGAL, AJAY P
• Application Number:
  US13/484,202
• Publication Number:
  US 20130223277A1
• Time in Patent Office: 1,252 Days
• US Class Current: 1/1
• CPC Class Codes: H04L 45/021 Ensuring consistency of routing table updates, e.g. by using epoch numbers
• CPC Class Codes: H04L 45/1283 with disjoint links
• CPC Class Codes: H04L 45/24 Multipath
• CPC Class Codes: H04L 49/357 Fibre channel switches
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]

Abstract

A method for determining disjoint multi-paths in a data center fabric network system, according to one embodiment, includes creating a topology of a data center fabric network system, wherein the system comprises a plurality of switches; determining paths between the plurality of switches; calculating one or more disjoint multi-paths from a source device to a destination device in the system; and writing the one or more disjoint multi-paths into a forwarding table of at least one of: the source device and a nearest shared switch to the source device.

Claims

1. A method for determining disjoint multi-paths in a data center fabric network system, the method comprising:

creating a topology of a data center fabric network system using a switch controller, wherein the data center fabric network system comprises a plurality of switches and the switch controller coupled directly to the plurality of switches via secure communication links, the plurality of switches being restricted from executing a discovery protocol to determine paths to other switches in the data center fabric network system;

determining paths between the plurality of switches using path calculations performed by the switch controller;

calculating one or more disjoint multi-paths from a source device to a destination device using the switch controller based on the topology, the calculating comprising determining whether a fully disjoint multi-path is available from the source device to the destination device, the calculated one or more disjoint multi-paths being fully disjoint based on a determination that a fully disjoint multi-path is available from the source device to the destination device and being partially disjoint based on a determination that a fully disjoint multi-path is not available from the source device to the destination device;

writing, using the switch controller, the one or more disjoint multi-paths into a forwarding table of the source device, the source device being configured to communicate with the switch controller during the writing of the one or more disjoint multi-paths into the forwarding table; and

writing, using the switch controller, the one or more disjoint multi-paths into a switch forwarding table of a nearest shared switch to the source device so that all traffic sent from the source device is routed through the nearest shared switch.

2. The method as recited in claim 1, further comprising storing the determined paths to a switch forwarding table in each switch in the determined paths of the plurality of switches.

3. The method as recited in claim 1, further comprising:

calculating, using the switch controller, at least one disjoint multi-path between each switch and all other switches in the system; and

writing the at least one disjoint multi-path into a switch forwarding table of each switch using the switch controller.

4. The method as recited in claim 3, further comprising:

detecting a change in the system using the switch controller;

re-calculating at least one disjoint multi-path between each switch and all other switches in the system in response to the change in the system, the re-calculating comprising determining whether a fully disjoint multi-path is available from the source device to the destination device, the calculated at least one disjoint multi-path being fully disjoint based on a determination that a fully disjoint multi-path is available from the source device to the destination device and being partially disjoint based on a determination that a fully disjoint multi-path is not available from the source device to the destination device; and

writing the at least one disjoint multi-path into the switch forwarding table of each switch using the switch controller,

wherein the change in the system comprises one of;

addition of a switch to the system, removal of a switch from the system, and change of a property of a switch in the system.

5. The method as recited in claim 4, wherein the change in the system comprises change of a property of a switch in the system.

6. The method as recited in claim 1, further comprising:

detecting a change in the system affecting a disjoint multi-path between the source device and a destination device using the switch controller;

re-calculating one or more disjoint multi-paths from the source device to the destination device in response to the change in the system, the re-calculating comprising determining whether a fully disjoint multi-path is available from the source device to the destination device, the calculated one or more disjoint multi-paths being fully disjoint based on a determination that a fully disjoint multi-path is available from the source device to the destination device and being partially disjoint based on a determination that a fully disjoint multi-path is not available from the source device to the destination device; and

writing, using the switch controller, the one or more re-calculated disjoint multi-paths into the forwarding table of at least one of;

the source device and the nearest shared switch to the source device,

wherein the change in the system comprises one of;

addition of a switch to the system, removal of a switch from the system, and change of a property of a switch in the system.

7. The method as recited in claim 6, wherein the change in the system comprises change of a property of a switch in the system.

8. The method as recited in claim 1, wherein the one or more disjoint multi-paths from the source device to the destination device are calculated in response to a request from the source device or the nearest shared switch to the source device.

9. The method as recited in claim 1, wherein each of the one or more disjoint multi-paths comprise at least two paths that are disjoint from one another resulting in at least one fully redundant path, and wherein a partially disjoint multi-path comprises at least two paths that share a minimum number of devices in the system.

10. The method as recited in claim 1, wherein a control plane for each of the plurality of switches is controlled by the switch controller.

11. The method as recited in claim 10, wherein the switch controller is adapted to operate as an OpenFlow controller.

12. The method as recited in claim 1, wherein the switch controller determines the paths between the plurality of switches.

13. A method for determining disjoint multi-paths in a data center fabric network system, the method comprising:

receiving, at a switch controller, reports of nearest neighbor devices from each of a plurality of switches in a data center fabric network system;

creating a topology of the data center fabric network system using the switch controller, wherein the data center fabric network system comprises the plurality of switches and the switch controller coupled directly to the plurality of switches via secure communication links, the plurality of switches being restricted from executing a discovery protocol to determine paths to other switches in the system;

determining paths between the plurality of switches, provided that the plurality of switches do not themselves execute a discovery protocol to determine paths to other switches in the system;

storing the determined paths, using the switch controller, to a switch forwarding table in each switch of the plurality of switches;

calculating one or more disjoint multi-paths from a source device to a destination device in the system using the switch controller, wherein each of the one or more disjoint multi-paths comprise at least two paths that are disjoint from one another to as great of an extent as possible given the topology of the data center fabric network system resulting in at least one fully redundant path between the source device and the destination device; and

writing, using the switch controller, the one or more disjoint multi-paths into at least a forwarding table of a nearest shared switch to the source device that is part of at least one disjoint multi-path.

14. The method as recited in claim 13, further comprising:

calculating at least one disjoint multi-path between each switch and all other switches in the system; and

writing the at least one disjoint multi-path into a switch forwarding table of each switch.

15. The method as recited in claim 14, further comprising:

detecting a change in the system;

re-calculating at least one disjoint multi-path between each switch and all other switches in the system in response to the change in the system; and

writing the at least one disjoint multi-path into the switch forwarding table of each switch,

wherein the change in the system comprises one of;

addition of a switch to the system, removal of a switch from the system, and change of a property of a switch in the system.

16. The method as recited in claim 13, further comprising:

detecting a change in the system affecting a disjoint multi-path between the source device and a destination device;

re-calculating one or more disjoint multi-paths from the source device to the destination device in response to the change in the system; and

writing the one or more re-calculated disjoint multi-paths into the forwarding table of at least one of;

the source device and the nearest shared switch to the source device,

wherein the change in the system comprises one of;

addition of a switch to the system, removal of a switch from the system, and change of a property of a switch in the system.

17. The method as recited in claim 13, wherein the one or more disjoint multi-paths from the source device to the destination device are calculated in response to a request from the source device and/or the nearest shared switch to the source device being received by the switch controller.