Method and system for reducing latency and congestion in fibre channel switches

• US 20050018603A1
• Filed: 07/20/2004
• Published: 01/27/2005
• 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: Dropps, Frank R., Verba, Craig M.
• Granted Patent: US 7,522,522 B2
• Time in Patent Office: Days
• US Class Current: 370/229
• CPC Class Codes: H04L 12/10 Current supply arrangements
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/20 Hop count for routing purposes, e.g. TTL
• CPC Class Codes: H04L 45/60 Router architectures
• 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 fibre channel frames using a fibre channel switch element is provided. The switch element includes, a port with a buffer having more than one memory slot for receiving fibre channel frames, wherein the port tracks a relative age of a first memory slot with respect to at least another memory slot; and frames are transmitted from a memory slot based on the relative age. The method includes, determining a relative age of a first memory slot with respect to at least another memory slot; and transmitting a frame from a memory slot based on the relative age. The method also includes, sending frames that have resided in a memory slot for a greater period compared to frames residing in at least another memory slot; and setting age bits in plural memory slots when frames are written and the relative age is determined based on the age bits. An aging table may be used to store the age bits of the plural memory slots.

Claims

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

determining a relative age of a first memory slot with respect to at least another memory slot; and

transmitting a frame from a memory slot based on the relative age.

2. The method of claim 1, further comprising:

sending frames that have resided in a memory slot for a greater period compared to frames residing in at least another memory slot.

3. The method of claim 1, further comprising:

setting age bits in plural memory slots when frames are written and the relative age is determined based on the age bits.

4. The method of claim 3, where an aging table may be used to store the age bits of the plural memory slots.

5. A fibre channel switch element for routing fibre channel, comprising:

means for determining a relative age of a first memory slot with respect to at least another memory slot; and

means for transmitting a frame from a memory slot based on the relative age.

6. The switch element of claim 5, further comprising:

means for sending frames that have resided in a memory slot for a greater period compared to frames residing in at least another memory slot.

7. The switch element of claim 5, further comprising:

means for setting age bits in plural memory slots when frames are written and the relative age is determined based on the age bits.

8. The switch element of claim 7, where an aging table may be used to store the age bits of the plural memory slots.

9. A fibre channel switch element for routing fibre channel frames, comprising:

a port with a buffer having more than one memory slot for receiving fibre channel frames, wherein the port tracks a relative age of a first memory slot with respect to at least another memory slot; and

frames are transmitted from a memory slot based on the relative age.

10. The switch element of claim 9, wherein a frame that has resided in a memory slot for a greater period compared to frames residing in at least another memory slot is given priority.

11. The switch element of claim 9, wherein age bits are set in plural memory slots when frames are written and the relative age is determined based on the age bits.

12. The switch element of claim 11, where an aging table may be used to store the age bits of the plural memory slots.