Architecture for a high-performance network/bus multiplexer interconnecting a network and a bus that transport data using multiple protocols

• US 6,065,087 A
• Filed: 05/21/1998
• Issued: 05/16/2000
• Est. Priority Date: 05/21/1998
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Tausheck, Eric G., Keaveny, Thomas A.
• Primary Examiner(s): Ray, Gopal C.
• Application Number:
  US09/082,738
• Time in Patent Office: 726 Days
• Field of Search: 710/126, 710/128, 710/129, 710/107, 710/2, 710/5, 710/62, 710/100, 710/101, 710/105, 710/131, 710/51, 710/52, 359/115, 359/117, 385/100, 709/223, 709/250, 709/213, 709/238, 370/401, 370/402, 370/911, 370/355, 340/825.52, 379/56.2, 711/102, 711/112, 711/147
• US Class Current: 710/315
• CPC Class Codes: G06F 13/4022 using switching circuits, e.g. switching matrix, connection or expansion network G06F13/4009 takes precedence
• CPC Class Codes: H04B 10/27 Arrangements for networking
• CPC Class Codes: H04L 12/4625 Single bridge functionality, e.g. connection of two networks over a single bridge

Abstract

A high-performance network/bus multiplexer that exchanges data transfer commands and data between different communications mediums, such as the Fibre Channel and one or more SCSI buses. High-performance is achieved by avoiding transmitting read bus operations through bus bridges, and by limiting contention for buses by connecting Fibre Channel host adapters to a first internal bus and SCSI adapters to a second internal bus.

Claims

1. A method for interconnecting a first communications medium, supporting a first transmission protocol that provides transmission of data transfer commands and data, with a second communications medium supporting a second transmission protocol that provides transmission of input/output commands and data, the method including:

providing a multiplexing hardware device having a local processor connected to a local memory by a local bus, the local bus connected to a first communications adapter that sends data and commands to, and that receives data and commands from, the first communications medium, and to a second communications adapter that sends data and commands to, and that receives data and commands from, the second communications medium, the local bus connected to a shared memory, the first communications adapter, and the second communications adapter by a bus bridge and an internal data bus, the internal bus, the local bus, and a combination of the internal bus, the local bus, and the bus bridge providing reading and writing operations that result in exchanges of data between the local memory, the shared memory, and the communications adapters;

receiving a data transfer command, directed to the second communications adapter, from the first communications medium by the first communications adapter;

writing the received data transfer command via the internal bus, the bus bridge, and the local bus to the local memory;

processing the data transfer command by the local processor and sending an input/output command corresponding to the received data transfer command to the second communications adapter via the local bus, the bus bridge, and the internal bus; and

executing an input/output operation corresponding to the received input/output command and exchanging data related to execution of the input/output operation with the first communications adapter, via the internal bus and shared memory, by the second communications adapter.

2. The method of claim 1 wherein sending an input/output command corresponding to the received data transfer command to the second communications adapter via the local bus, the bus bridge, and the internal bus further includes transmitting indications of buffer locations within the shared memory by the local processor to the shared memory via the local bus, the bus bridge, and the internal bus.

3. The method of claim 1 further including:

after executing the input/output command by the second communications adapter,

writing a result by the second communications adapter into the local memory via the internal bus, the bus bridge, and the local bus; and

reading the result by the local processor via the local bus, and writing a message corresponding to the result by the local processor via the local bus, the bus bridge, and the internal bus to the first communications adapter which then forwards the result to the first communications medium.

4. The method of claim 1 wherein control data structures for controlling operation of the first communication adapter and the second communication adapter are partitioned between the local memory and the shared memory so that the local processor and the communications adapters do not need to employ reading operations via a combination of the internal bus, the local bus, and the bus bridge in order to access the control data structures during the exchange of the data transfer command and the data between the first communications adapter and the second communications adapter.

5. The method of claim 1 wherein the received data transfer command is a read data transfer command, wherein the input/output command corresponding to the read data transfer command is a read input/output command, and wherein the data related to the execution of the read input/output operation is received by the second communications adapter from the second communications medium, written by the second communications adapter to the shared memory via the internal bus, read from the shared memory by the first communications adapter via the internal bus, and forwarded to the first communications medium by the first communications adapter.

6. The method of claim 1 wherein the received data transfer command is a write data transfer command, wherein the input/output command corresponding to the write data transfer command is a write input/output command, and wherein the data related to the execution of the write input/output operation is received from the first communications medium by the first communications adapter, written by the first communications adapter to the shared memory via the internal bus, read from the shared memory by the second communications adapter via the internal bus, and forwarded to the second communications medium by the second communications adapter.

7. The method of claim 1 wherein the multiplexing hardware device includes two internal buses and two bus bridges, wherein the shared memory is a dual-ported shared memory, the first communications adapter connected to the dual-ported shared memory via a first internal bus and to the local bus via the first internal bus and a first bus bridge, the second communications adapter connected to the dual-ported shared memory via a second internal bus and to the local bus via the second internal bus and a second bus bridge, wherein the first communications adapter does not issue reading or writing operations to the second internal bus and the second communications adapter does not issue reading or writing operations to the first internal bus, and wherein control data structures for controlling operation of the first communication adapter and the second communication adapter are partitioned between the local memory and the shared memory so that the local processor and the communications adapters do not need to employ reading operations via a combination of the local bus, the internal bus, and the bus bridge connected to the internal bus in order to access the control data structures during the exchange of the data transfer command and the data between the first communications adapter and the second communications adapter.

8. The method of claim 1 wherein a number of different data transfer commands and data can be concurrently exchanged between the first communication adapter and the second communication adapter within the multiplexing hardware device.

9. The method of claim 1 wherein the first communications adapter receives the data transfer command from, and exchanges the data with, a remote computer via the first communications medium.

10. The method of claim 1 wherein the second communications adapter forwards the input/output command to, and exchanges the data with, a mass storage device via the second communications medium.

11. The method of claim 10 wherein the mass storage device is selected from a disk drive, a CD-ROM drive, and a tape drive.

12. The method of claim 11 wherein the first communications medium is a Fibre Channel and wherein the second communications medium is a SCSI bus.

13. The method of claim 12 wherein the local processor assigns a Fibre Channel RX_-- ID to each received data transfer command and uses the assigned RX_-- ID to identify control data structure entries within the control data structures related to each received data transfer command.

14. The method of claim 13 wherein the local processor assigns a SCSI queue tag to each input/output operation corresponding to a received data transfer command and uses the assigned SCSI queue tag to identify control data structure entries within the control data structures related to each input/output operation.

15. A method for interconnecting a first communications medium, supporting a first transmission protocol that provides transmission of data transfer commands and data, with a second communications medium supporting a second transmission protocol that provides transmission of input/output commands and data, the method including:

providing a local processor connected to a local memory by a local bus, the local bus connected, via a first bus bridge and a first internal bus, to a dual-ported shared memory and to a first communications adapter that sends data and commands to, and that receives data and commands from, the first communications medium, the local bus connected, via a second bus bridge and a second internal bus, to the dual-ported shared memory and a second communications adapter that sends data and commands to, and that receives data and commands from, the second communications medium, the local bus, the internal buses, and combinations of an internal bus selected from either of the two internal buses, the local bus, and the bus bridge connected to the selected internal bus providing reading and writing operations for exchanging data between the local memory, the dual-ported shared memory, and the communications adapters;

receiving a data transfer command, directed to the second communications adapter, from the first communications medium by the first communications adapter;

writing the received data transfer command via the first internal bus, the first bus bridge, and the local bus to the local memory;

processing the data transfer command by the local processor and sending an input/output command corresponding to the received data transfer command to the second communications adapter; and

executing an input/output operation corresponding to the received input/output command and exchanging data related to execution of the input/output operation with the first communications adapter via the second internal bus, the dual-ported shared memory, and the first internal bus, by the second communications adapter.

16. The method of claim 15 wherein sending an input/output command corresponding to the received data transfer command to the second communications adapter via the local bus, the second bus bridge, and the second internal bus further includes transmitting indications of buffer locations within the dual-ported shared memory by the local processor to the dual-ported shared memory via the local bus, the second bus bridge, and the second internal bus.

17. The method of claim 15 further including:

after executing the input/output command by the second communications adapter,

writing a result by the second communications adapter into the local memory via the second internal bus, the second bus bridge, and the local bus; and

reading the result by the local processor via the local bus, and writing a message corresponding to the result by the local processor via the local bus, the first bus bridge, and the first internal bus to the first communications adapter for forwarding by the first communications adapter to the first communications medium.

18. The method of claim 15 wherein control data structures for controlling operation of the first communication adapter and the second communication adapter are partitioned between the local memory and the dual-ported shared memory so that the local processor and the communications adapters do not need to employ reading operations via combinations of the internal buss, the local bus, and the bus bridges in order to access the control data structures during the exchange of the data transfer command and the data between the first communications adapter and the second communications adapter.

19. The method of claim 15 wherein the received data transfer command is a read data transfer command, wherein the input/output command corresponding to the read data transfer command is a read input/output command, and wherein the data related to the execution of the read input/output operation is received by the second communications adapter from the second communications medium, written by the second communications adapter to the dual-ported shared memory via the second internal bus, read from the dual-ported shared memory by the first communications adapter via the first internal bus, and forwarded to the first communications medium by the first communications adapter.

20. The method of claim 15 wherein the received data transfer command is a Write data transfer command, wherein the input/output command corresponding to the write data transfer command is a write input/output command, and wherein the data related to the execution of the write input/output operation is received from the first communications medium by the first communications adapter, written by the first communications adapter to the dual-ported shared memory via the first internal bus, read from the dual-ported shared memory by the second communications adapter via the second internal bus, and forwarded to the second communications medium by the second communications adapter.

21. The method of claim 15 wherein a number of different data transfer commands and data can be concurrently exchanged between the first communication adapter and the second communication adapter within the multiplexing hardware device.

22. The method of claim 15 wherein the first communications adapter receives the data transfer command and exchanges the data via the first communications medium with a remote computer.

23. The method of claim 15 wherein the second communications adapter forwards the input/output command and exchanges the data with a mass storage device via the second communications medium.

24. The method of claim 23 wherein the mass storage device is selected from a disk drive, a CD-ROM drive, and a tape drive.

25. The method of claim 24 wherein the first communications medium is a Fibre Channel and wherein the second communications medium is a SCSI bus.

26. The method of claim 25 wherein the local processor assigns a Fibre Channel RX_-- ID to each received data transfer command and uses the assigned RX_-- ID to identify control data structure entries within the control data structures related to each received data transfer command.

27. The method of claim 25 wherein the local processor assigns a SCSI queue tag to each input/output operation corresponding to a received data transfer command and uses the assigned SCSI queue tag to identify control data structure entries within the control data structures related to each input/output operation.

28. A multiplexing hardware device that interconnects a first communications medium, supporting a first transmission protocol that provides transmission of data transfer commands and data, with a second communications medium supporting a second transmission protocol providing transmission of input/output commands and data, the multiplexing hardware device including:

a local processor that translates data transfer commands and messages from the first transmission protocol to the second transmission protocol;

a local memory that stores control data structures and queues which the local processor uses to control the communications adapters and track data transfer commands as they are processed within the multiplexing hardware device;

a local bus that interconnects the local processor with the local memory and that supports reading and writing operations;

a first communications adapter that sends data and commands to, and that receives data and commands from, the first communications medium;

a second communications adapter that sends data and input/output commands to, and that receives data and commands from, the second communications medium;

a shared memory that stores control data structures and queues which the local processor uses to control the communications adapters and that stores data exchanged between the first communications adapter and the second communications adapter;

an internal bus to which the communications adapters and shared memory are connected and that supports reading and writing operations; and

a bus bridge that interconnects the internal bus and the local bus.

29. The multiplexing hardware device of claim 28 wherein, during the processing of received data transfer commands by the multiplexing hardware device, the local processor and the first and second communications adapters only transmit writing operations through the bus bridge.

30. The multiplexing hardware device of claim 29 wherein, when the first communications adapter receives a data transfer command from the first communications medium, the multiplexing hardware device processes the received data transfer command by:

writing the received data transfer command by the first communications adapter via the internal bus, the bus bridge, and the local bus to the local memory;

processing the data transfer command by the local processor and sending an input/output command corresponding to the received data transfer command to the second communications adapter; and

executing, by the second communications adapter, an input/output operation corresponding to the received input/output command and exchanging data, by the second communications adapter, related to execution of the input/output operation with the first communications adapter via the internal bus and shared memory.

31. The multiplexing hardware device of claim 30 further including:

after executing the input/output command by the second communications adapter,

writing a result by the second communications adapter into the local memory via the internal bus, the bus bridge, and the local bus; and

reading the result by the local processor via the local bus, and writing a message corresponding to the result by the local processor via the local bus, the bus bridge, and the internal bus to the first communications adapter for forwarding by the first communications adapter to the first communications medium.

32. The multiplexing hardware device of claim 30 wherein the received data transfer command is a read data transfer command, wherein the input/output command corresponding to the read data transfer command is a read input/output command, and wherein the data related to the execution of the read input/output operation is received by the second communications adapter from the second communications medium, written by the second communications adapter to the shared memory via the internal bus, read from the shared memory by the first communications adapter via the internal bus, and forwarded to the first communications medium by the first communications adapter.

33. The multiplexing hardware device of claim 30 wherein the received data transfer command is a write data transfer command, wherein the input/output command corresponding to the write data transfer command is a write input/output command, and wherein the data related to the execution of the write input/output operation is received from the first communications medium by the first communications adapter, written by the first communications adapter to the shared memory via the internal bus, read from the shared memory by the second communications adapter via the internal bus, and forwarded to the second communications medium by the second communications adapter.

34. The multiplexing hardware device of claim 30 wherein control data structures for controlling operation of the first communication adapter and the second communication adapter are partitioned between the local memory and the shared memory so that the local processor and the communications adapters do not need to employ reading operations via a combination of the internal bus, the local bus, and the bus bridge in order to access the control data structures during the exchange of data transfer commands and data between the first communications adapter and the second communications adapter.

35. The multiplexing hardware device of claim 28 wherein the first communications medium is a Fibre Channel, wherein the second communications medium is a SCSI bus, and wherein the data transfer commands are initiated by one or more remote computers connected to the Fibre Channel and result in the second communications adapter directing mass storage devices, wherein the mass storage devices are selected from disk drives, tape drives, and CD-ROM drives, connected to the SCSI bus, to exchange data with the one or more remote computers via the Fibre Channel, the internal bus., and shared memory within the multiplexing hardware device, and the SCSI bus.

36. The multiplexing hardware device of claim 35, wherein a number of Fibre Channel communications adapters and a number of SCSI communications adapters are connected to the internal bus.

37. The multiplexing hardware devices of claim 36 wherein a large number of data transfer commands are concurrently processed within the multiplexing hardware device.

38. A multiplexing hardware device that interconnects a first communications medium supporting a first transmission protocol that provides transmission of data transfer commands and data with a second communications medium supporting a second transmission protocol that provides transmission of input/output commands and data, the multiplexing hardware device including:

a local processor that translates data transfer commands and messages from the first transmission protocol to the second transmission protocol;

a local memory that stores control data structures and queues which the local processor uses to control the communications adapters and track data transfer commands as they are processed within the multiplexing hardware device;

a local bus that interconnects the local processor with the local memory and that supports reading and writing operations;

a first communications adapter that sends data and commands to, and that receives data and commands from, the first communications medium;

a second communications adapter that sends data and input/output commands to, and that receives data and commands from, the second communications medium;

a dual-ported shared memory for storing control data structures and queues which the local processor uses to control the communications adapters and that stores data exchanged between the first communications adapter and the second communications adapter;

a first internal bus to which the first communications adapter and dual-ported memory are connected and that supports reading and writing operations;

a first bus bridge that interconnects the first internal bus and the local bus;

a second internal bus to which the second communications adapter and dual-ported memory are connected and that supports reading and writing operations; and

a second bus bridge that interconnects the second internal bus and the local bus.

39. The multiplexing hardware device of claim 38 wherein the local processor and the communications adapters only transmit reading operations through the bus bridges during the processing of received data transfer commands by the multiplexing hardware device.

40. The multiplexing hardware device of claim 39 wherein, when the first communications adapter receives a data transfer command from the first communications medium, the multiplexing hardware device processes the received data transfer command by:

writing the received data transfer command by the first communications adapter via the first internal bus, the first bus bridge, and the local bus to the local memory;

processing the data transfer command by the local processor and sending an input/output command corresponding to the received data transfer command to the second communications adapter via the local bus, and one of the bus bridges and the corresponding internal bus that is connected to the bus bridge; and

executing, by the second communications adapter, an input/output operation corresponding to the received command by the second communications adapter and exchanging, by the second communications adapter, data related to execution of the input/output operation with the first communications adapter via the internal buses and dual-ported shared memory.

41. The multiplexing hardware device of claim 40 further including:

after executing the input/output command by the second communications adapter,

writing a result by the second communications adapter into the local memory via the first internal bus, the first bus bridge, and the local bus; and

reading the result by the local processor via the local bus, and writing a message corresponding to the result by the local processor via the local bus, the first bus bridge, and the first internal bus to the first communications adapter for forwarding by the first communications adapter to the first communications medium.

42. The multiplexing hardware device of claim 40 wherein the received data transfer command is a read data transfer command, wherein the input/output command corresponding to the read data transfer command is a read input/output command, and wherein the data related to the execution of the read input/output operation is received by the second communications adapter from the second communications medium, written by the second communications adapter to the dual-ported shared memory via the second internal bus, read from the dual-ported shared memory by the first communications adapter via the first internal bus, and forwarded to the first communications medium by the first communications adapter.

43. The multiplexing hardware device of claim 40 wherein the received data transfer command is a write data transfer command, wherein the input/output command corresponding to the write data transfer command is a write input/output command, and wherein the data related to the execution of the write input/output operation is received from the first communications medium by the first communications adapter, written by the first communications adapter to the dual-ported shared memory via the first internal bus, read from the dual-ported shared memory by the second communications adapter via the second internal bus, and forwarded to the second communications medium by the second communications adapter.

44. The multiplexing hardware device of claim 40 wherein control data structures for controlling operation of the first communication adapter and the second communication adapter are partitioned between the local memory and the shared memory so that the local processor and the communications adapters do not need to employ reading operations via a combination of an internal bus selected from among the two internal buses, the local bus, and a bus bridge connected to the selected internal bus in order to access the control data structures during the exchange of data transfer commands and data between the first communications adapter and the second communications adapter.

45. The multiplexing hardware device of claim 38 wherein the first communications medium is a Fibre Channel, wherein the second communications medium is a SCSI bus, and wherein the data transfer commands are initiated by one or more remote computers connected to the Fibre Channel and result in the second communications adapter directing mass storage devices, wherein the mass storage devices are selected from disk drives, tape drives, and CD-ROM drives, connected to the SCSI bus, to exchange data with the one or more remote computers via the Fibre Channel, the internal bus and dual-ported shared memory within the multiplexing hardware device, and the SCSI bus.

46. The multiplexing hardware device of claim 45 wherein a number of Fibre Channel communications adapters are connected to the first internal bus and wherein a number of SCSI communications adapters are connected to the second internal bus.

47. The multiplexing hardware device of claim 38 wherein a large number of data transfer commands are concurrently processed within the multiplexing hardware device.