Address translation in fibre channel switches

• US 20060159081A1
• Filed: 01/18/2005
• Published: 07/20/2006
• Est. Priority Date: 01/18/2005
• 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.
• Granted Patent: US 7,519,058 B2
• Time in Patent Office: Days
• US Class Current: 370/389
• CPC Class Codes: H04L 49/101 using crossbar or matrix
• CPC Class Codes: H04L 49/25 Routing or path finding in a switch fabric
• 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 49/357 Fibre channel switches

Abstract

A fibre channel switch element and method for processing frames in a fibre channel network is provided. The switch element includes an address mapping cache that receives an incoming fibre channel frame in a receive and/or transmit segment, wherein the address mapping cache compares a D_ID of an incoming frame in the receive segment and/or a S_ID in the transmit segment; and if a FR_Header is received then a D_ID or S_ID is compared from a fibre channel header that follows the FR_Header; and if a compare fabric identifier flag is set, then the fabric identifier is compared. The address mapping cache may also be used for routing frames from one virtual fabric to another by comparing a VF_ID field to a Virtual fabric identifier in a VFT_Header.

Claims

1. A method for processing frames in a fibre channel network, comprising:

determining if an incoming frame includes a FR_Header;

determining if there is a match from an address mapping cache;

routing the frame as a local fabric frame, if there is no match from the address mapping cache and the incoming frame did not include a FR_Header; and

building a FR_Header if there is a match from the address mapping cache and the incoming frame did not include a FR_Header and updating the incoming frame so that it can be routed to a local fabric or remote fabric destination.

2. The method of claim 1, further comprising:

routing the incoming frame as an inter-fabric frame if there is no match from the address mapping cache and the incoming frame includes a FR_Header.

3. The method of claim 1, further comprising:

removing the FR_Header if the incoming frame includes a FR_Header and there is a match from the address mapping cache; and

modifying an incoming frame header so that the incoming frame can be routed as a local fabric frame.

4. The method of claim 1, wherein the incoming frame is modified so that a proxy address can be used for routing the frame and the proxy address will depend on whether a frame is destined for a local or remote fabric.

5. The method of claim 1, wherein a cyclic redundancy code (“

CRC”

) is updated for the incoming frame.

6. A method for processing fibre channel frames in a transmit segment of a fibre channel switch, comprising:

determining if a transmit frame includes a FR_Header;

determining if there is a match from an address mapping cache;

routing a transmit frame to a local fabric device if there is no matching entry from an address mapping cache; and

building a FR_Header and updating a transmit frame header if there is no FR_Header in the transmit frame and there is a match from the address mapping cache, wherein a D_ID and/or S_ID in the transmit frame header is updated.

7. The method of claim 6, further comprising:

routing a transmit frame as an inter-fabric frame, if the transmit frame includes a FR_Header and there is no match from the address mapping cache.

8. The method of claim 7, wherein the FR_Header in the transmit frame is used to send the frame to a destination that may be located in a remote fabric.

9. The method of claim 6, further comprising:

deleting a FR_Header if the transmit frame includes a FR_Header and there is a match from the address mapping cache; and

routing the transmit frame as a local fabric frame.

10. The method of claim 9, wherein a proxy address is set up for a transmit port to route the transmit frame as a local fabric frame.

11. The method of claim 6, wherein the transmit frame'"'"'s cyclic redundancy code is updated.

12. A fibre channel switch element, comprising:

a port with an address mapping cache that receives an incoming fibre channel frame in a receive and/or transmit segment, wherein the address mapping cache compares a D_ID of an incoming frame in the receive segment and/or a S_ID in the transmit segment; and

if a FR_Header is received then a D_ID or S_ID is compared from a fibre channel header that follows the FR_Header; and

if a compare fabric identifier flag is set, then the fabric identifier is compared.

13. The fibre channel switch element of claim 12 wherein a new port address field is substituted in a frame header if there is match from the address mapping cache, wherein the substituted value may be a D_ID or S_ID.

14. The fibre channel switch element of claim 12, wherein if there is a match from the address mapping cache and an incoming frame includes a FR_Header, then the FR-Header is deleted.

15. The fibre channel switch element of claim 12, wherein a new Fabric identifier is used for a destination fabric that is associated with a proxy address for an entry that matches an address mapping cache entry for a received frame.

16. A fibre channel switch element comprising:

a port with an address mapping cache that is used for routing frames from one virtual fabric to another by comparing a VF_ID field to a Virtual fabric identifier in a VFT_Header.

17. The fibre channel switch element of claim 16, wherein if a received frame includes a VFT_Header and a VF_ID and a D_ID and a S_ID match address mapping cache entries, then the VF ID, D_ID and S_ID values are replaced.