Methods and apparatus for fiber channel interconnection of private loop devices

• US 6,118,776 A
• Filed: 08/07/1997
• Issued: 09/12/2000
• Est. Priority Date: 02/18/1997
• Status: Expired due to Term

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Vixel Corporation (Broadcom, Inc.)
• Inventors: Berman, Stuart B.
• Primary Examiner(s): Vu, Huy D.
• Assistant Examiner(s): PHAN, MAN U
• Application Number:
  US08/907,385
• Time in Patent Office: 1,132 Days
• Field of Search: 370/401, 370/403, 370/404, 370/405, 370/406, 370/422, 370/424, 370/425, 370/407, 370/351, 370/352, 370/355, 395/200, 395/286, 359/161, 359/197, 359/200
• US Class Current: 370/351
• CPC Class Codes: H04L 12/427 with decentralised control
• CPC Class Codes: H04L 12/4637 Interconnected ring systems
• CPC Class Codes: H04L 45/24 Multipath
• CPC Class Codes: H04L 45/30 Routing of multiclass traffic
• CPC Class Codes: H04L 45/745 Address table lookup; Address filtering
• CPC Class Codes: H04L 49/101 using crossbar or matrix
• CPC Class Codes: H04L 49/253 using establishment or release of connections between ports
• CPC Class Codes: H04L 49/254 Centralised controller, i.e. arbitration or scheduling
• CPC Class Codes: H04L 49/3009 Header conversion, routing tables or routing tags
• CPC Class Codes: H04L 49/351 for local area network [LAN], e.g. Ethernet switches
• CPC Class Codes: H04L 49/352 Gigabit ethernet switching [GBPS]
• CPC Class Codes: H04L 49/357 Fibre channel switches
• CPC Class Codes: H04L 49/604 Hybrid IP/Ethernet switches
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04Q 11/0066 Provisions for optical burst or packet networks
• CPC Class Codes: H04Q 2011/0073 Provisions for forwarding or routing, e.g. lookup tables
• CPC Class Codes: H04Q 2011/0092 Ring

Abstract

Methods and apparatus for Fiber Channel interconnection is provided between a plurality of private loop devices through a Fiber Channel private loop device interconnect system. In the preferred embodiments, the Fiber Channel private loop device interconnect system is a fabric or an intelligent bridging hub. In one aspect of this invention, a Fiber Channel private loop device is connected to two or more Arbitrated Loops containing, or adapted to contain, one or more private loop devices. Preferably, the interconnect system includes a routing filter to filter incoming Arbitrated Loop physical addresses (ALPAs) to determine which Fiber Channel frames must attempt to be routed through the fabric. Numerous topologies of interconnect systems may be achieved. In another aspect of this invention, a method is provided for implementing a logical loop of private loop devices by segmenting the logical loop into a plurality of sets, assigning each set to a physical Arbitrated Loop and connecting the Arbitrated Loops to a Fiber Channel private loop device interconnect system. Additional methods are provided for restricting attached devices to Arbitrated Loop physical addresses within certain ranges. Additionally, methods are provided for resetting hosts, the method generally comprising the steps of detecting the addition of a storage device to a first Arbitrated Loop, and thereafter, resetting the Arbitrated Loop or loops on which a host or hosts reside on second Arbitrated Loop. Methods for operation with use of SCSI initiators generate a link service reject when no address match is found, or when an address match is found, but where no device with the destination ALPA exists on the Arbitrated Loop corresponding to the destination.

Claims

1. A system for interconnecting a Fibre Channel Arbitrated Loop having one or more directly attached Private Loop Devices and a second device to communicate Fibre Channel frames, comprising;

a first Arbitrated Loop containing one or more private loop devices,

a second device,

a Fibre Channel private loop device interconnect system, the interconnect system including;

a first port containing a first port control module coupled to the first Arbitrated Loop,

a second port containing a second port control nodule coupled to the second device,

the first and second port control modules each containing a Fibre Channel Arbitrated Loop Port State Machine, the Loop Port State Machine including;

an active L_-- Port, implementing the Fibre Channel Arbitrated Loop protocol, including the generation of ARBs, OPNs and Closes,

the first loop port state machine providing point to point connection between the first loop port state machine and a private loop device on the first Arbitrated Loop,

route determination apparatus for selecting a route between the port control modules, and

connectivity apparatus coupled to the first and second port control modules and to the route determination apparatus for switching frames between ports under control of the route determination apparatus,

whereby Fibre Channel frames are transferred between a private loop device on the first Arbitrated Loop and the second device.

3. The interconnection system of claim 1 or 2 wherein a private loop device includes storage.

4. The interconnection system of claim 3 wherein the storage includes JBODs.

5. The interconnection system of claim 3 wherein the storage includes RAIDS.

6. The interconnection system of claim 3 wherein the storage includes tape drives.

7. The interconnection system of claim 1 or 2 wherein a said private loop device includes a host.

8. The interconnection system of claim 1 or 2 further including multiple public loop devices on the first Arbitrated Loop.

9. The interconnection system of claim 1 or 2 wherein a said private loop device includes a bridge.

10. The interconnection system of claim 9 wherein the bridge is a SCSI to Fibre Channel bridge.

11. The interconnection system of claim 1 or 2 wherein a said private loop device includes a router.

12. The interconnection system of claim 11 wherein the router connects Fibre Channel to asynchronous transfer mode (ATM).

13. The Interconnection System of claim 11 wherein the router connects Fibre Channel to Ethernet.

14. The Interconnection System of claim 13 wherein the router connects Fibre Channel to Fast Ethernet.

15. The Interconnection System of claim 11 wherein the router connects Fibre Channel to a Gigabit Ethernet.

16. The interconnection system of claim 1 or 2 wherein at least one arbitrated loop comprises a hub.

17. The interconnection system of claims 1 or 2 including redundant connections between the Fibre Channel private loop device interconnect system and an attached storage unit or host unit.

29. The interconnect system of claim 1 or 2 wherein the Fibre Channel private loop device interconnect system generates a Loop Initialization Primitive (LIP) on certain predefined events.

30. The interconnect system of claim 29 wherein the predefined event is the addition of selected devices to the interconnect system.

31. The interconnect system of claim 29 where the predefined event is the detection of link errors on a port.

32. The interconnection system of claims 1 or 2 including redundant connections between the Fibre Channel private loop device interconnect system and a bridge or router.

33. The interconnect system of claims 1 or 2 wherein the port control modules include an 8B/10B encoder/decoder (Endec).

34. The interconnect system of claims 1 or 2 wherein at least one of the port control modules includes a direct fabric attached state machine.

35. The interconnect system of claims 1 or 2 wherein the port control modules include one or more frame buffers.

36. The interconnect system of claims 1 or 2 wherein the port control modules includes an R_-- Rdy primitive flow control state machine.

37. The interconnect system of claims 1 or 2 wherein the port control modules includes an FC2 header decoder.

38. The interconnect system of claims 1 or 2 wherein the port control modules includes a Destination Identifier (D_-- ID) extractor.

41. The interconnection system of claim 3 wherein the storage includes a Fibre Channel to SCSI bridge.

42. The interconnection system of claim 1 or 2 wherein the second device includes storage.

43. The interconnection system of claim 42 wherein the storage includes JBODs.

44. The interconnection system of claim 42 wherein the storage includes RAIDS.

45. The interconnection system of claim 42 wherein the storage includes tape drives.

46. The interconnection system of claim 42 wherein the storage includes a Fibre Channel to SCSI bridge.

47. The interconnection system of claim 1 or 2 wherein the second device includes a host.

48. The interconnection system of claim 1 or 2 wherein the second device is a public loop device.

49. The interconnection system of claim 1 or 2 wherein the second device is a private loop device.

50. The interconnection system of claim 1 or 2 wherein the second device is a device which connects by the direct fabric attached topology.

51. The interconnection system of claim 9 wherein the bridge is an asynchronous transfer mode (ATM) to Fibre Channel bridge.

52. The interconnection system of claim 1 or 2 wherein the second device includes a router.

53. The interconnection system of claim 52 wherein the router connects Fibre Channel to asynchronous transfer mode (ATM).

54. The interconnection system of claim 52 wherein the router connects Fibre Channel to Ethernet.

55. The interconnection system of claim 54 wherein the router connects Fibre Channel to Fast Ethernet.

56. The interconnection system of claim 54 wherein the router connects Fibre Channel to a Gigabit Ethernet.

57. The interconnection system of claim 1 or 2 wherein the Fibre Channel private loop device interconnect system is a Fiber Channel fabric.

58. The interconnection system of claim 57 which is capable of routing frames between a private loop device on the first Arbitrated Loop and the second device by using the Destination Identifier (D_-- ID) information in the FC-2 frame header.

59. The interconnect system of claims 1 or 2 wherein the route determination apparatus is centrally located.

60. The interconnect system of claims 1 or 2 wherein the route determination apparatus routes at least on the ALPA in the Destination Identifier (D_-- ID) information in the FC-2 frame header.

61. The interconnect system of claims 1 or 2 wherein the interconnect system includes a non-blocking switch core.

62. The interconnect system of claims 1 or 2 wherein the private loop interconnect system further includes a fabric control module.

63. The interconnect system of claim 62 wherein the fabric control module includes a control processor.

64. The interconnect system of claim 62 wherein the fabric control module is connected directly to the connectivity apparatus.

65. The interconnect system of claim 62 wherein the fabric control module sends frames through the port control modules to the attached devices.

66. The interconnection system of claim 1 or 2 wherein the Fibre Channel private loop device interconnect system is an intelligent bridging hub.

67. The interconnection system of claim 1 or 2 wherein the Fibre Channel private loop device interconnect system implements route filtering.

68. The interconnection system of claim 1 or 2 wherein the Fibre Channel private loop device interconnect system restricts ALPA value selection by an attached device.

69. The interconnection system of claim 1 or 2 wherein the Fibre Channel private loop device interconnect system implements I/O probe spoofing.

70. The interconnection system of claim 1 or 2 wherein the Fibre Channel private loop device interconnect system resets a first port which has a non-storage device connected to it upon the addition of storage to a second port.

71. The interconnection system of claim 1 or 2 where the second device connects to the second port via a second arbitrated loop.

72. The interconnection system of claim 67 wherein route filtering includes ALPA selection.

76. The interconnection system of claim 57 wherein the fabric is a Fibre Channel switch.

77. The Interconnection System of claim 76 wherein the interconnect system includes more than one switch.

78. The interconnection system of claim 57 wherein the fabric is a router.

2. A system for interconnecting a Fibre Channel Arbitrated Loop having one or more directly attached Private Loop Devices and a second device to communicate Fibre Channel frames, comprising:

a first Arbitrated Loop adapted to contain one or more private loop devices,

a Fibre Channel private loop device interconnect system, the interconnect system including;

a first port containing a first port control module adapted to be coupled to the first Arbitrated Loop,

a second port containing a second port control module adapted to be coupled to the second device,

the first and second port control modules each containing a Fibre Channel Arbitrated Loop Port State Machine, the Loop Port State Machine including;

an active L_-- Port, implementing the Fibre Channel Arbitrated Loop protocol, including the generation of ARBs, OPNs and Closes,

the first Loop Port State Machine providing point to point connection between the first Loop Port State Machine and a private loop device on the first Arbitrated Loop,

route determination apparatus for selecting a route between the port control modules, and

connectivity apparatus coupled to the first and second port control modules and to the route determination apparatus for switching frames between ports under control of the route determination apparatus,

whereby Fibre Channel frames are transferred between a private loop device on the first Arbitrated Loop and the second device.

18. A method for routing frames between a private loop device on a first Arbitrated Loop and one or more private loop devices on at least a second Arbitrated Loop via a private loop interconnect system having a plurality of ports, each port containing a port control module, the port containing an active L_-- Port, comprising the steps of:

receiving frames over the first Arbitrated Loop at a connected port of a Fiber Channel private loop device interconnect system, and filtering said frames by;

(1) forwarding the frame on the first Arbitrated Loop if it has an address on the first Arbitrated Loop and

(2) generating at a port control module an "open" response on the first Arbitrated Loop, if the address is not on the first Arbitrated Loop.

19. The method for routing frames of claim 18 further including the step of attempting to route the frame to the address which is not on the first Arbitrated Loop.

20. The method for routing frames of claim 18 further including the step of buffering in the private loop device interconnect system frames destined to private loop devices not on the first Arbitrated Loop if the route cannot be made immediately.

21. The method for routing frames of claim 18 further including the step of comparing destination addresses with a predefined table.

22. The method of claim 18 wherein the filtering is achieved by:

applying a mask to the received ALPA,

comparing the results with a preconfigured value to determine whether to filter the frame.

39. The method for routing frames of claim 21 wherein the destination address is the D_-- ID field of the FC-2 frame header.

23. A method for configuring multiple Fibre Channel Arbitrated Loops of private loop devices, each private loop device on an Arbitrated Loop having a domain and area address value of zero and an Arbitrated Loop Physical Address (ALPA), comprising the steps of:

dividing the ALPAs into non-overlapping sets,

assigning each set to a separate physical Arbitrated Loop, and

during loop initialization, restricting the attached private loop devices to choose from the assigned set.

24. The method of claim 23 further including the step of interconnecting at least certain of the Arbitrated Loops through a Fibre Channel.

25. A method for operation of an interconnection system, the system including more than one Arbitrated Loop, at least one loop containing storage and one loop containing a non-storage device, the devices attached to the loops being private loop devices, the loops being connected to a Fibre Channel private loop device interconnect system, comprising the steps of:

detecting an addition of a storage device to a first Arbitrated Loop, and

resetting by transmitting a Loop Initialization Primitive (LIP) on all of the ports having Arbitrated Loops which include a non-storage device but not transmitting a Loop Initialization Primitive (LIP) on the ports having Arbitrated Loops containing only storage devices.

40. The method for operation of an interconnection system of claim 25, wherein the non-storage device includes a SCSI initiator.

73. The method for operation of an interconnection system of claim 25, wherein the storage device includes a SCSI target device.

26. A method for operation of an interconnection system, the system including more than one Arbitrated Loop, at least one loop adapted to contain a storage device and one loop containing a non-storage device, the devices attached to the loops being private loop devices, the loops being connected to a Fibre Channel private loop device interconnect system, the private loop device interconnect system including a plurality of ports, each port containing a port control module, the port control module containing an active L_-- Port, comprising the steps of:

receiving PLOGI I/O probes at a Fibre Channel private loop device interconnect system,

performing address lookup for the received PLOGI I/O probes, and if a match exists in the lookup,

routing I/O probes to private loop devices on the Fibre Channel private loop device interconnect system.

74. The method for operation of an interconnect system of claim 26 wherein the non-storage device is a SCSI initiator.

75. The method for operation of an interconnect system of claim 26 storage device includes a SCSI target device.

27. A method for operation of an interconnection system, the system including more than one Arbitrated Loop, at least one loop adapted to contain a storage device and one loop containing a non-storage device, the devices attached to the loops being private loop devices, the loops being connected to a Fibre Channel private loop device interconnect system, the interconnect system containing a controller comprising the steps of:

receiving PLOGI I/O probes at a Fibre Channel private loop device interconnect system,

performing address lookup for the received PLOGI I/O probes, and

routing the I/O probes to the Fibre Channel private loop device interconnect system controller and returning a Link Service Reject (LS_-- RJT) if either no match is found upon address lookup or if a match is found upon address lookup, but no device with the destination ALPA exists on the Arbitrated Loop corresponding to the destination.

28. The method of claim 27 wherein the determination that no device with the destination ALPA exists on the Arbitrated Loop is performed by the steps of:

sending a frame on a loop, and

simultaneously receiving the same frame on the same loop.

79. A method for operation of an interconnection system, the system including at least a first Arbitrated Loop and a second Arbitrated Loop, each of the first Arbitrated Loop and second Arbitrated Loop having private loop devices attached to the Loops, the Private Loop Devices on first Arbitrated Loop being able to communicate with Private Loop Devices on the second Arbitrated Loop, the interconnect system including a plurality of ports, each port containing a port control module, the port control module containing an active L_-- Port. comprising the steps of:

detecting a loop initialization event on the first Arbitrated Loop, and

initializing the first Arbitrated Loop without affecting the other attached loops.

80. The method for operation of an Interconnection System of claim 79, wherein at least one loop is adapted to contain a SCSI target device.

81. The method for operation of an interconnection system of claim 79, wherein at least one loop is adapted to contain a SCSI initiator device.