Method and system for programmable data dependant network routing

• US 7,573,909 B2
• Filed: 07/20/2004
• Issued: 08/11/2009
• Est. Priority Date: 07/21/2003
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: QLogic Corporation (Marvell Technology Group Limited)
• Inventors: Verba, Craig M., Dropps, Frank R, Kohlwey, Ernest G
• Primary Examiner(s): Ngo; Ricky
• Assistant Examiner(s): PATEL, CHANDRAHAS B
• Application Number:
  US10/894,627
• Publication Number:
  US 20050018680A1
• Time in Patent Office: 1,848 Days
• Field of Search: 370/60, 370/216, 370/252, 370/321, 370/352, 370/401, 370/469, 709/203, 709/208, 709/213, 709/226, 709/231, 709/245, 710/36
• US Class Current: 370/469
• 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 49/357 Fibre channel switches

Abstract

A method and system for routing fiber channel frames using a fiber channel switch element is provided. The switch element includes, a look up table that is indexed by domain, area, a virtual storage area number and/or AL_PA values of frames entering the fiber channel switch element; and logic for generating a column select signal that is used to select a column from the look up table for frame routing information. The switch element also includes logic for validating a frame route by performing word depth match. A register is used to load look up table entries and column entries are selected based on the column select signal. The method includes, indexing a look up table with plural fiber channel frame header values; selecting a table value for routing a fiber channel frame based on a column select signal; and routing the frame if a route is valid.

Claims

1. A method for routing fibre channel frames using a fibre channel switch element, comprising the steps of:

(a) receiving a fibre channel frame at a port of the fibre channel switch element having a plurality of ports;

(b) indexing a look up table by using (i) a Domain value for routing the fibre channel frame to another fibre channel switch, (ii) an Area value for routing the fibre channel frame within the fibre channel switch that received the fibre channel frame, (iii) a Virtual Storage Area Network identifier (VSAN#) for routing the fibre channel frame within a Virtual Storage Area Network, and (iv) an Arbitrated Loop Physical Address (AL_PA) value included in a header of the fibre channel frame;

wherein the look up table includes a plurality of columns for storing destination information indexed by the Domain value, the Area value, the Virtual Storage Network identifier and the Arbitrated Loop Physical Address;

(c) selecting a look up table value from one of the plurality of columns of the look up table, for routing a fibre channel frame based on a column select signal generated by a hardware logic of the fibre channel switch element; and

(d) routing the frame if a route based on the selected table value is valid.

2. The method of claim 1, wherein a frame'"'"'s destination identifier field (D_ID) is used to select a column for frame routing information.

3. The method of claim 1, wherein a valid route is determined by matching a correct word depth with frame word depth.

4. The method of claim 1, wherein a frame'"'"'s originator exchange identification field OX_ID) is used to select a column for frame routing information.

5. The method of claim 1, wherein a frame'"'"'s source identifier field (S_ID) value is used to select a column for frame routing information.

6. The method of claim 1, wherein a frame'"'"'s TYPE field is used to select a column for frame routing information.

7. The method of claim 1, wherein bits other than a TYPE field of a frame are used to select a column for frame routing information.

8. The method of claim 1, wherein the column select signal generated after a plurality of fields are input to the hardware logic and one of the input is selected to generate the column select signal.

9. The method of claim 8, wherein the hardware logic is a multiplexer and the plurality of inputs are a destination identifier field (D_ID), a source identifier field (S_ID), a virtual storage area network identifier, an originate exchange identification field (OX_ID), a TYPE field, and a decode fibre channel header type field.

10. A fibre channel switch element configured to select a route from amongst a plurality of routes for routing fibre channel frames, the fibre channel switch element comprising:

at least one port for receiving and transmitting a fibre channel frame;

a look up table with a plurality of columns that is indexed by (i) a Domain value for routing the fibre channel frame to another fibre channel switch, (ii) an Area value for routing the fibre channel frame within the fibre channel switch that received the fibre channel frame, (iii) a Virtual Storage Area Network identifier (VSAN#) for routing the fibre channel frame within a Virtual Storage Area Network, and (iv) an Arbitrated Loop Physical Address (AL_PA) value; and

a hardware logic that receives a plurality of inputs and based on one of the inputs generates a column select signal, wherein the column select signal is used to select a column from the one of the plurality of columns of the look up table to route fibre channel frames, if the route based on the selected column is valid.

11. The switch element of claim 10, further comprising:

hardware logic module for validating a frame route by performing word depth match.

12. The switch element of claim 10, wherein in a register is used to load look up table entries and column entries are selected based on the column select signal.

13. The switch element of claim 10 wherein a frame'"'"'s originator exchange identification field (OX_ID) is used to select a column for frame routing information.

14. The switch element of claim 10, wherein a frame'"'"'s destination identifier (D_ID) is used to select a column for frame routing information.

15. The switch element of claim 10, wherein a frame'"'"'s TYPE field is used to select a column for frame routing information.

16. The switch of claim 10, wherein bits other than a TYPE field of a frame are used to select a column for frame routing information.

17. The switch element of claim 10, wherein a frame'"'"'s source identifier (S_ID) value is used to select a column for frame routing information.

18. A network system, comprising:

a host computing system for sending and receiving information;

at least one storage system for storing information; and

at least one fibre channel switch element configured to select a route from amongst a plurality of routes, for routing fibre channel frames in the network, the fibre channel switch element includes;

at least one port for receiving and transmitting a fibre channel frame;

a look up table with a plurality of columns that is indexed by (i) a Domain value for routing the fibre channel frame to a other fibre channel switch, (ii) an Area value for routing the fibre channel frame within the fibre channel switch that received the fibre channel frame, (iii) a Virtual Storage Area Network identifier (VSAN#) for routing the fibre channel frame within a Virtual Storage Area Network, and (iv) an Arbitrated Loop Physical Address (AL_PA) value; and

a hardware logic that receives a plurality of inputs and based on one of the inputs generates a column select signal, wherein the column select signal is used to select a column from the one of the plurality of columns of the look up table to route fibre channel frames, if a route based on the selected column is valid.

19. The system of claim 18, wherein the hardware logic is a multiplexer and the plurality of inputs are a destination identifier field (D_ID), a source identifier field (S_ID), a virtual storage area network identifier, an originator exchange identification field (OX_ID), a TYPE field, and a decode fibre channel header type field.

20. The system of claim 18, wherein a register is used to load look up table entries and column entries are selected based on the column select signal.