Method and system for selecting virtual lanes in fibre channel switches

• US 7,525,983 B2
• Filed: 07/20/2004
• Issued: 04/28/2009
• Est. Priority Date: 07/21/2003
• Status: Expired due to Fees

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: QLogic Corporation (Marvell Technology Group Limited)
• Inventors: Gustafson, William J, Dropps, Frank R., Ross, Edward C.
• Primary Examiner(s): Phunkulh; Bob A
• Application Number:
  US10/894,827
• Publication Number:
  US 20050018621A1
• Time in Patent Office: 1,743 Days
• Field of Search: None
• US Class Current: 370/437
• CPC Class Codes: H04L 49/25 Routing or path finding in a switch fabric
• CPC Class Codes: H04L 49/357 Fibre channel switches

Abstract

A method for assigning virtual lanes (VL) in a fibre channel switch is provided. The fibre channel switch element includes a virtual lane cache that can compare incoming frame parameters based on which virtual lanes may be assigned; and a register to store parameters used for virtual lane assignment. The method includes, determining if VL assignment is to be based on an incoming frame parameter or a programmed value; determining if an incoming frame is a preferred frame; and assigning a preferred routing priority if the incoming frame is designated as a preferred frame. The method also includes, determining if a fabric topology is known; and assigning virtual lanes based on a known fabric topology.

Claims

1. A method for assigning virtual lanes (VL) in a fibre channel switch having a plurality of ports, comprising:

(a) receiving an incoming frame at a port from among the plurality of ports;

wherein each of the plurality of ports include a receive segment to receive the incoming frame and a transmit segment for transmitting the incoming frame;

(b) determining if a destination identifier and a source identifier in a frame header for the incoming frame matches a destination identifier value and a source identifier value stored at the port receiving the incoming frame;

(c) if there is no match in step (b), then assigning a virtual lane based on a frame parameter within the frame header;

(d) if there is a match in step (b) then assigning a virtual lane based on a parameter from a virtual lane cache; and

(f) if there is a match in step (b), determining if an indicator for indicating that the received frame is a preferred frame is set; and

(g) if the indicator in step (f) is set, then assigning a virtual lane with a preferred routing priority.

2. Th method of claim 1, wherein VL assignment criteria varies for the plurality of ports of the fibre channel switch element.

3. The method of claim 1, wherein different links coupled to the plurality of ports of the fibre channel switch element have different VL assignment criteria.

4. The method of claim 3, wherein each end of a link has different VL assignment criteria.

5. The method of claim 1, wherein in VL assignment is performed for one or more of N_Ports and loop port.

6. The method of claim 1, wherein in step (c) one or more of a destination identifier (D_ID), a source identifier (S_ID), an originator identifier (OX_ID), and a virtual storage area network identifier (VSAN_ID) is used for assigning a virtual lane.

7. The method of claim 1, wherein a bit in a control register is set to indicate if the received incoming frame is a preferred frame.

8. A system for assigning virtual lanes in a fibre channel switch having a plurality of ports, comprising:

a receive segment at a port from among the plurality of ports, for receiving an incoming frame; and

a virtual lane cache that compares frame parameters in the incoming frame header with parameters stored at the port; and

if there is a match, then assigns the virtual lanes base on parameters stored within a register; and

if there is no match, then assigns the virtual lanes based on frame parameters included within the incoming frame header;

wherin the virtual lane cache includes a control word register and a port pair register and their values are used for virtual lane assignment.

9. A system for assigning virtual lanes in a fibre channel switch having a plurality of ports, comprising:

a receive segment at a port from among the plurality of ports, for receiving an incoming frame; and

a virtual lane cache that compares frame parameters in the incoming frame header with parameters stored at the port; and

if there is a match, then assigns the virtual lanes based on parameters stored within a register; and

if there is no match, then assigns the virtual lanes based on frame parameters included within the incoming frame header;

wherein the virtual lane cache includes a control word register and a port pair register and their values are used for virtual lane assignment; and

wherein the virtual lane cache includes logic for comparing incoming frame parameters with values stored in the port pair word register.

10. A system for assigning virtual lanes in a fibre channel switch having a plurality of ports, comprising:

a receive segment at a port from among the plurality of ports, for receiving an incoming frame; and

a virtual lane cache that compares frame parameters in the incoming frame header with parameters stored at the port; and

if there is a match, then assigns the virtual lanes based on parameters stored within a register; and

if there is no match, then assigns the virtual lanes based on frame parameters included within the incoming frame header;

wherein one or more of destination identifier (D_ID), a source identifier (S_ID), an originator identifier (OX_ID), and a virtual storage area network identifier (VSAN_ID) is used for assigning a virtual lane.

11. A method for assigning virtual lanes (VL) in a fibre channel switch having a plurality of ports, comprising:

(a) receiving an incoming frame at a port from among the plurality of ports;

wherein each of the plurality of ports include a receive segment to receive the incoming frame and a transmit segment for transmitting the incoming frame;

(b) determining if a destination identifier and source identifier in a frame header for the incoming frame matches a destination identifier value and a source identifier value stored at the port receiving the incoming frame;

(c) if there is no match in step (b), then assigning a virtual lane has based on a frame parameter within the frame header;

(d) if there is a match in step (b), then assigning a virtual lane based on a parameter stored a the port, and

if there is a match in step (b) determining if an indicator for indicating that the received frame is a preferred frame is set; and

if the indicator is set, then assigning a virtual lane with a preferred routing priority.

12. The method of claim 11, wherein a bit in a control register is set to indicate if the received incoming frame is a preferred frame.

13. A method for assigning virtual lanes (VL) in a fibre channel switch having a plurality of ports, comprising:

a) receiving an incoming frame at a port from among the plurality of ports;

wherein each of the plurality of ports include a receive segment to receive the incoming frame and a transmit segment for transmitting the incoming frame;

b) determining if a destination identifier and a source identifier in a frame header for the incoming frame matches a destination identifier value and a source identifier value stored at the port receiving the incoming frame;

(c) if there is no match in step (b), then assigning a virtual lane based on a frame parameter within the frame header;

(d)if there is a match in step (b), then assigning a virtual lane based on a parameter stored at the port;

wherein in step (c), one or more of a destination identifier (D_D), a source identifier (S_ID), an originator identifier (OX_ID), and a virtual storage area network identifier (VSAN_ID) is used for assigning a virtual lane.