Address translation in fibre channel switches

• US 7,519,058 B2
• Filed: 01/18/2005
• Issued: 04/14/2009
• Est. Priority Date: 01/18/2005
• Status: Expired due to Fees

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: QLogic Corporation (Marvell Technology Group Limited)
• Inventors: Dropps, Frank R.
• Primary Examiner(s): Pezzlo; John
• Application Number:
  US11/037,922
• Publication Number:
  US 20060159081A1
• Time in Patent Office: 1,547 Days
• Field of Search: 370352-356, 370/400, 370/401, 370/419, 370/389
• 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:

(a) determining if an incoming frame received at a receive segment of a port of a fibre channel switch element includes an inter fabric frame header (“

FR_Header”

);

(b) if there in no FR_Header in step (a), determining if there is a match from a hardware based address mapping cache;

(c) routing the frame as a local fabric frame, if there is no match from the address mapping cache in step (b) and the incoming frame did not include the FR_Header as determined in step (a);

(d) if there is said match from the address mapping cache in step (b) and the incoming frame did not include the FR_Header as determined in step (a) building the FR_Header; and

(e) updating the incoming frame with a new fabric identifier so that the incoming frame is routed as an inter-fabric frame or as the local fabric frame.

2. The method of claim 1, further comprising;

routing the incoming frame as the inter-fabric frame after determining that there is no match from the address mapping cache and the incoming frame includes the FR_Header as determined in step (a) of claim 1.

3. The method of claim 1, further comprising:

removing the FR_Header, if the incoming frame includes the FR_Header, as determined in step (a) of claim 1 and after determining that there is said match from the address mapping cache; and

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

4. The method of claim 1, wherein the incoming frame is modified in step (d) of claim 1 with a proxy address for the port and the proxy address depends on whether the incoming frame destination is for a local fabric or a remote fabric.

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

CRC”

) is updated for the incoming frame.

6. The method of claim 1, wherein the address mapping cache uses a compare field, a control field and an output field for routing the incoming frame;

wherein the compare field includes a port address and a fabric identifier field in an inter-fabric frame identifier header (“

FR_Header”

);

the port address includes a destination identifier (D_ID) and a source identifier (S_ID); and

if the FR_header is present in the incoming frame, then to route the frame, the D_ID is compared;

wherein the control field includes (i) a FR_Header flag, which if set, is used to compare the FR_Header field in the incoming frame; and

if the FR_Header flag is not set, then FR_Header field is ignored;

(ii) a compare fabric identifier only flag, which when set, is used to compare a fabric identifier; and

(iii) a D_ID flag, which when set, is used to compare and substitute the D_ID; and

wherein he output field includes (i) a new port address field that is used for address substitution when using one of the compare fields provides a match;

(ii) an add header flag, which when set, is used to add the FR_Header to the incoming frame;

(iii) a delete header flag, which when set, is used to remove the FR_header flag; and

(iv) a new fabric identifier that is used for a destination fabric associated with proxy address that matches an address map cache entry.

9. The method of claim 7, further comprising:

if the transmit frame includes the FR_Header in step (a) of claim 1;

deleting the FR_Header after determining that there is said match from the address mapping cache; and

routing the transmit frame as the local fabric frame.

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

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

(a) determining if a transmit frame includes an inter-fabric frame header (“

FR_Header”

);

(b) if the FR_Header is not present in step (a), determining if there is a match from a hardware based address mapping cache;

(c) routing the transmit frame to a local fabric if there is no matching entry from an address mapping cache in step (b); and

(d) if there is no FR_Header in the transmit frame in step (a) and there is said match from the address mapping cache in step (b);

building the FR_Header for the transmit frame, wherein the FR_Header depends on whether the destination fabric of the transmit frame is the local fabric or a remote fabric, and the FR_Header is inserted in the transmit frame with a fabric identifier for the destination fabric.

8. The method of claim 7, further comprising:

routing the transmit frame as an inter-fabric frame, if the transmit frame includes said FR_Header as determined in step (a) of claim 7, and if there is no match from the address mapping cache.

11. The method of claim 7, wherein the transmit frame'"'"'s cyclic redundancy code is updated.

12. The method of Claim 7, wherein the address mapping cache uses a compare field, a control field and an output field for routing the transmit frame to the local fabric and the remote fabric;

wherein the compare field includes a port address and a fabric identifier field in an inter-fabric frame identifier head (“

FR_Header”

);

the port address includes a destination identifier (D_ID) and a source identifier (S_ID); and

if the FR_header is present in the transmit frame, then to route the transmit frame, the S_ID is compared;

wherein the control field includes (i) a FR_Header flag, which if set, is used to compare the FR_Header field in the transmit frame; and

if the FR_Header flag is not set, then FR_Header field is ignored;

(ii) compare fabric identifier only flag, which when set, is used to compare a fabric identifier; and

(iii) a D_ID flag, which when set, is used to compare and substitute the D_ID; and

wherein the output field includes (i) a new port address field that is used for address substitution when using one of the compare fields provides a match;

(ii) an add header flag, which when set, is used to add the FR_Header to the transmit frame;

(iii) a delete header flag, which when set, is used to remove the FR_header flag; and

(iv) a new fabric identifier that is used for a destination fabric associated with a proxy address that matches an address map cache entry.

13. A fibre channel switch element, comprising:

a port having a receive segment and a transmit segment for receiving and transmitting a fibre channel frame;

wherein the port includes a hardware based address mapping cache that is used for routing the fibre channel frame to local fabric or to a remote fabric;

the address mapping cache using a compare field, a control field and an output field for routing the fibre channel frame to the local fabric and the remote fabric;

wherein the compare field includes port address and a fabric identifier field in an inter-fabric frame identifier header (“

FR_Header”

);

the port address includes a destination identifier (D_ID ) and a source identifier (S_ID); and

if the FR_Header is present in the fibre channel frame, then to route fibre channel frame, the D_ID is compared, if the fibre channel frame is in the receive segment, and the S_ID is compared, if the fibre channel frame is in the transmit segment;

wherein the output field includes (i) a FR_Head flag, which if set, is used to compare the FR_Header field in the fibre channel frame; and

if the FR_Header flag is not set, then FR_Header field is ignored;

(ii) a compare fabric identifier only flag, which when set, is used to compare a fabric identifier; and

(iii) a D_ID flag, which when set, is used to compare and substitute the D_ID; and

wherein the output field includes (i) a new port address field that is used for address substitution when using one of the compare fields provides a match;

(ii) an add header flag, which when set, is used to add the FR_Header to the fibre channel frame;

(iii) a delete header flag, which when set, is used to remove the FR_header flag; and

(iv) a new fabric identifier that is used for destination fabric associated with a proxy address that matches an address map cache entry.

14. The fibre channel switch element of claim 13 wherein the D_ID or the S_ID address field in the fibre channel frame is substituted if there is a match from the address mapping cache.

15. The fibre channel switch element of claim 13, wherein if there is said match from the address mapping cache and the fibre channel frame includes the FR_Header, then the FR_Header is deleted if the delete header flag is set.

16. The fibre channel switch element of claim 13, wherein the new Fabric identifier used for the destination fabric associated with the proxy address, is a part of the FR_Header.

17. The fibre channel switch element of claim 13, wherein the

address mapping cache is also used for routing frames from one virtual fabric to another by comparing a virtual fabric identifier (“

VF_ID”

) field to a Virtual fabric identifier in a virtual fabric tagging header (VFT_Header).

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