Method and system for LUN remapping in fibre channel networks

• US 20060072616A1
• Filed: 10/01/2004
• Published: 04/06/2006
• Est. Priority Date: 10/01/2004
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: QLogic Corporation (Marvell Technology Group Limited)
• Inventors: Dropps, Frank R., Ross, Edward C., Betker, Steven M.
• Granted Patent: US 7,593,997 B2
• Time in Patent Office: Days
• US Class Current: 370/474
• CPC Class Codes: G06F 12/0813 with a network or matrix configuration
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/0661 Format or protocol conversion arrangements
• CPC Class Codes: G06F 3/0664 at device level, e.g. emulation of a storage device or system
• CPC Class Codes: G06F 3/0683 Plurality of storage devices
• CPC Class Codes: H04L 49/101 using crossbar or matrix
• CPC Class Codes: H04L 49/3009 Header conversion, routing tables or routing tags
• CPC Class Codes: H04L 49/357 Fibre channel switches

Abstract

A Fibre Channel switch element in a Fibre Channel network is provided. The Fibre Channel switch element includes a port that replaces a logical unit number (“LUN”) field value in a FCP_CMND frame. The port includes a LUN Mapping cache for replacing the LUN field value in a FCP_CMND frame. The LUN Mapping cache may also generate a value that is added to or subtracted from the LUN field value in the FCP_CMND frame. A control bit is used to activate LUN Mapping cache for mapping LUN values.

Claims

1. A Fibre Channel switch element in a Fibre Channel network, comprising:

a port that replaces a logical unit number (“

LUN”

) field value in a FCP_CMND frame with a new LUN field value.

2. The Fibre Channel switch element of claim 1, wherein for the FCP_CMND frame where the LUN field value is replaced also has a CRC field replaced by a newly computed CRC using the new LUN field value.

3. The Fibre Channel switch element of claim 1, wherein the port includes a LUN Mapping cache for replacing the LUN field value in a FCP_CMND frame.

4. The Fibre Channel switch element of claim 3, wherein the LUN Mapping cache generates a value that is added to or subtracted from the LUN field value in the FCP_CMND frame.

5. The Fibre Channel switch element of claim 3, wherein the LUN Mapping cache generates a LUN field value that is directly substituted in the FCP_CMND frame.

6. The Fibre Channel switch element of claim 3, wherein a D_ID and/or S_ID and/or LUN field of the FCP_CMND frame is compared to a LUN mapping cache entry to identify a frame for a LUN field value substitution.

7. The Fibre Channel switch element of claim 3, wherein a D_ID and/or S_ID and/or LUN field of the FCP_CMND frame is compared to a LUN mapping cache entry to obtain a LUN field substitution value.

8. The Fibre Channel switch Element of claim 3, wherein the LUN Mapping Cache simultaneously compares plural frame fields to generate a hit signal.

9. The Fibre Channel switch element of claim 3, wherein a control bit is used to activate LUN Mapping cache for mapping LUN values.

10. The Fibre Channel switch element of claim 3, wherein a multiple hit signal may be generated after the LUN Mapping cache compares plural frame fields.

11. The Fibre Channel switch element of claim 3, wherein the LUN mapping cache performs LUN mapping for incoming and outgoing frames.

12. A storage area network (“

SAN”

), comprising;

a Fibre Channel switch element with a port that replaces a logical unit number (“

LUN”

) field value in a FCP_CMND frame with a new LUN field value.

13. The SAN of claim 12, wherein the port includes a LUN Mapping cache for replacing the LUN field value in the FCP_CMND frame.

14. The SAN of claim 13, wherein the LUN Mapping cache generates a value that is added to or subtracted from the LUN field value in the FCP_CMND frame.

15. The SAN of claim 13, wherein the LUN Mapping Cache simultaneously compares plural frame fields to generate a hit signal.

16. The SAN of claim 13, wherein a control bit is used to activate LUN Mapping cache for mapping LUN values.

17. The SAN of claim 13, wherein a multiple hit signal may be generated after the LUN Mapping cache compares plural frame fields.

18. The SAN of claim 13, wherein the LUN mapping cache performs LUN mapping for incoming and outgoing frames.

19. A method for processing FCP_CMND frames in a storage area network, comprising:

setting up a LUN mapping cache;

comparing plural FCP_CMND frame fields; and

substituting a LUN field value in the FCP_CMND frame with a LUN mapping cache entry.

20. The method of claim 19, wherein a LUN field value in the FCP_CMND frame is offset by a certain value.