Methods and apparatus for characterizing a route in a fibre channel fabric

• US 7,830,809 B2
• Filed: 03/02/2007
• Issued: 11/09/2010
• Est. Priority Date: 06/12/2002
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Cometto, Maurilio, Edsall, Thomas James
• Primary Examiner(s): NGUYEN, STEVEN H D
• Application Number:
  US11/713,341
• Publication Number:
  US 20070153816A1
• Time in Patent Office: 1,348 Days
• Field of Search: None
• US Class Current: 370/249
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/115 using a dedicated packet
• CPC Class Codes: H04L 47/283 in response to processing delays, e.g. caused by jitter or round trip time [RTT]

Abstract

A fibre channel frame is received at a first fibre channel switch. The fibre channel frame includes time stamp information associated with fibre channel switches between a second fibre channel switch and the first fibre channel switch. A time-to-live (TTL) value included in the fibre channel frame is determined. The fibre channel frame is sent back to the second fibre channel switch upon determining the TTL value included in the fibre channel frame.

Claims

1. A method, comprising:

receiving a fibre channel frame at a first fibre channel switch, the fibre channel frame including time stamp information associated with a plurality of fibre channel switches between a second fibre channel switch and the first fibre channel switch;

determining a time-to-live (TTL) value included in the fibre channel frame;

sending the fibre channel frame back to the second fibre channel switch upon determining the TTL value included in the fibre channel frame.

2. The method of claim 1, wherein the fibre channel frame is sent back to the second fibre channel switch when the TTL value is determined to be 1.

3. The method of claim 1, wherein the fibre channel frame includes a loop back field indicating that the fibre channel frame should be looped back when the TTL value reaches 1.

4. The method of claim 1, wherein the fiber channel frame traverses a first route to reach the first fibre channel switch.

5. The method of claim 4, wherein the fibre channel frame traverses a second route to return to the second fibre channel switch, wherein the second route is different from the first route.

6. The method of claim 5, wherein the fibre channel frame is time stamped by a plurality of first route fibre channel switches and a plurality of second route fibre channel switches.

7. The method of claim 6, wherein the fibre channel frame is further time stamped by the first fibre channel switch.

8. The method of claim 1, wherein the first fibre channel switch and the second fibre channel switch are synchronized.

9. The method of claim 1, wherein the first fibre channel switch is a core fibre channel switch and the second fibre channel switch is a source fibre channel switch.

10. The method of claim 1, wherein the source fibre channel switch and the plurality of fibre channel switches are synchronized.

11. An apparatus, comprising:

an interface operable to receive a fibre channel frame, the fibre channel frame including time stamp information associated with a plurality of fibre channel switches between the apparatus and a source fibre channel switch;

a processor operable to determine a time-to-live (TTL) value included in the fibre channel frame;

wherein the interface is further operable to send the fibre channel frame back to the source fibre channel switch upon determining the TTL value included in the fibre channel frame.

12. The apparatus of claim 11, wherein the fibre channel frame is sent back to the source fibre channel switch when the TTL value is determined to be 1.

13. The apparatus of claim 11, wherein the fibre channel frame includes a loop back field indicating that the fibre channel frame should be looped back when the TTL value reaches 1.

14. The apparatus of claim 11, wherein the fiber channel frame traverses a first route to reach the source fibre channel switch.

15. The apparatus of claim 14, wherein the fibre channel frame traverses a second route to return to the source fibre channel switch, wherein the second route is different from the first route.

16. The apparatus of claim 15, wherein the fibre channel frame is time stamped by a plurality of first route fibre channel switches and a plurality of second route fibre channel switches.

17. The apparatus of claim 16, wherein the fibre channel frame is further time stamped by the source fibre channel switch.

18. A system, comprising:

means for receiving a fibre channel frame at a first fibre channel switch, the fibre channel frame including time stamp information associated with a plurality of fibre channel switches between a second fibre channel switch and the first fibre channel switch;

means for determining a time-to-live (TTL) value included in the fibre channel frame;

means for sending the fibre channel frame back to the second fibre channel switch upon determining the TTL value included in the fibre channel frame.

19. The system of claim 18, wherein the fibre channel frame is sent back to the second fibre channel switch when the TTL value is determined to be 1.

20. The system of claim 18, wherein the TTL value is incremented before sending the fibre channel frame back to the second fibre channel switch.