Trunking inter-switch links

• US 6,819,654 B2
• Filed: 03/06/2003
• Issued: 11/16/2004
• Est. Priority Date: 09/25/2001
• Status: Expired due to Term

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Mcdata Corporation (Broadcom, Inc.)
• Inventors: Beal, David D., Yang, Henry S., Soloway, Stuart R.
• Primary Examiner(s): QURESHI, AFSAR M
• Application Number:
  US10/383,032
• Publication Number:
  US 20030165137A1
• Time in Patent Office: 621 Days
• Field of Search: 370/230, 370/231, 370/232, 370/235, 370/236, 370/237, 370/238, 370/239, 370/253, 370/386, 370/389, 370/392, 370/400, 370/412, 370/414, 370/458, 370/221, 370/225, 709/230, 709/232, 709/234, 709/239, 709/241, 398/5, 398/19, 398/45
• US Class Current: 370/238
• 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 45/123 Evaluation of link metrics techniques for monitoring network metrics H04L43/08
• CPC Class Codes: H04L 45/24 Multipath
• CPC Class Codes: H04L 45/245 Link aggregation, e.g. trunking
• CPC Class Codes: H04L 45/38 Flow based routing
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/11 Identifying congestion
• CPC Class Codes: H04L 47/122 by diverting traffic away from congested entities
• CPC Class Codes: H04L 47/29 using a combination of thresholds
• CPC Class Codes: H04L 49/25 Routing or path finding in a switch fabric
• CPC Class Codes: H04L 49/30 Peripheral units, e.g. input or output ports
• CPC Class Codes: H04L 49/357 Fibre channel switches
• CPC Class Codes: H04L 49/552 by ensuring the integrity of packets received through redundant connections
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A method and apparatus for routing frames through a fiber channel fabric to make the most efficient possible use of redundant inter-switch links between neighboring switches. The inter-switch links may have different bandwidths. The flow between adjacent switches is monitored to determine various local usage statistics and periodically adjust routing tables to move data flows from congested links to lightly loaded links.

Claims

1. A method of routing a flow through a switch in a fibre channel fabric comprising:

receiving traffic at a port coupled to said switch;

identifying said flow from said traffic using header information;

determining at least one path operative for routing said flow through said fibre channel fabric; and

rerouting said flow from a first link in said at least one path to a second link in said at least one path based upon operating performance information in addition to topology information.

2. The method of claim 1, wherein said at least one path comprises a plurality of paths from said switch to at least one adjacent switch.

3. The method of claim 2, wherein said at least one adjacent switch comprises at least two adjacent switches.

4. The method of claim 1, wherein said act of determining at least one path comprises determining at least one shortest path.

5. The method of claim 1 wherein said flow comprises a plurality of data frames arriving on a receive port associated with said first switch, wherein said data frames are to be routed to a destination switch in said fabric based upon said header information.

6. The method of claim 1 wherein said operating performance information comprises a congested link condition.

7. The method of claim 6 wherein said congested link condition comprises a first condition resulting from an additional flow on said first link resulting in said first link exceeding a first congestion threshold, wherein said first congestion threshold defines a percentage of bandwidth on said first link in relation to the total available amount of bandwidth on said first link.

8. The method of claim 1 wherein said operating performance information comprises a metered off first link condition.

9. The method of claim 1, wherein said header information comprises a domain portion of a destination identification information.

10. The method of claim 1, wherein said act of identifying said flow from said traffic using header information further comprises identifying said flow using receive port information.

11. A method of routing a flow on at least one path in a fibre channel fabric, said at least one path comprising a source switch and a destination switch, wherein at least one switch pair in said at least one path is coupled by a plurality of links, said method comprising:

determining said at least one path between said source switch and said destination switch;

routing said flow over a first link coupling said at least one switch pair in said at least one path, said at least one switch pair having the same originating switch; and

rerouting said flow to a second link coupling said at least one switch pair based upon operating performance information in addition to topology information.

12. The method of claim 11, wherein said first link comprises a link from said originating switch to a first switch and said second link comprises a link from said originating switch to a second switch.

13. The method of claim 11, wherein said act of determining at least one path comprises determining at least one shortest path.

14. The method of claim 11 wherein said act of determining said at least on path comprises determining a shortest path using a fibre channel shortest path first (FSPF) algorithm.

15. The method of claim 14 wherein said FSPF algorithm comprises:

assigning a cost to each of said plurality of links, wherein said cost is proportional to a reciprocal of bandwidth; and

determining one or more links from said plurality of links that provides a lowest cost.

16. The method of claim 11 wherein said flow comprises a plurality of data frames arriving on a receive port associated with said switch pair, wherein said data frames are to be routed based upon header information and receive port information.

17. The method of claim 16 wherein said header information comprises a portion of said destination identification.

18. The method of claim 11 wherein said operating performance information comprises a congested link condition.

19. The method of claim 18 wherein said congested link condition comprises a first condition resulting in said first link exceeding a first congestion threshold, wherein said first congestion threshold defines a percentage of bandwidth on said first link in relation to the total available amount of bandwidth on said first link.

20. The method of claim 11 wherein said operating performance information comprises a metered off first link condition.

21. The method of claim 20 wherein said metered off first link condition comprises a condition resulting from a portion of time that said first link is unable to transmit due to lack of available resources to handle said flow.

22. The method of claim 21 wherein said lack of available resources is measured by credits, wherein said credits determine the number of frame buffers available in the receiving port of said first link.

23. The method of claim 11 wherein said operating performance information comprises a condition where the delay of said first link exceeds a predetermined threshold.

24. A method for routing a plurality of packets through a switch in a packet-switching network comprising:

identifying a flow from said plurality of packets;

determining at least one shortest path operative for routing said flow through said packet-switching network, wherein said at least one shortest path comprises a first link and second link; and

rerouting said flow from said first link to said second link based upon operating performance information in addition to topology information.