Techniques for using frame deep loopback capabilities for extended link diagnostics in fibre channel storage area networks

Patent metadata

Field	Value
Publication number	US-11252067-B2
Application number	US-201916280870-A
Country	US
Kind code	B2
Filing date	Feb 20, 2019
Priority date	Feb 24, 2017
Publication date	Feb 15, 2022
Grant date	Feb 15, 2022

Abstract

One embodiment is a method including configuring a first network element of a fibre channel (“FC”) network as a generator element, wherein the generator employs a link diagnostic protocol to cause a second network element comprising a peer of the first network element as a reflector element, wherein the first and second elements are connected via a link; entering a first diagnostic phase, wherein in the first diagnostic phase, diagnostic capabilities of the first and second elements are determined; and subsequent to completion of the first diagnostic phase, entering a second diagnostic phase in which a deep loopback test is performed, wherein the deep loopback test comprises a frame level loopback test for exposing an issue in a path between the first and second network elements beyond a Media Access Control (“MAC”) layer.

First claim

What is claimed is:

1. A method comprising:
configuring a first network element of a fibre channel (“FC”) network as a generator element, the generator element configured to reject a login request and force a second network element to operate as a reflector element that negotiates diagnostic mode parameters with the generator element when the generator element employs a link diagnostic protocol, the first network element and the second network element connected via a link;
determining diagnostic capabilities of the first network element and the second network element via a diagnostic phase, wherein one or more supported loopback tests are identified;
identifying the farthest loopback of the supported loopbacks;
performing the one or more supported loopback tests on a data path or a control path; and
exposing an issue on the data path or the control path between the first network element and the second network element based on a loopback test of the one or more supported loopback tests.

2. The method of claim 1 , wherein the loopback test of the one or more supported loopback tests is performed in addition to other loopback tests.

3. The method of claim 1 , wherein the first network element is an F port of an FC switch and the second network element is an N port of a host bus adapter (“HBA”).

4. The method of claim 3 , wherein frames of the loopback test are looped back at an FC driver of the second network element.

5. The method of claim 1 , wherein the first network element is an E port of one of a host bus adapter (“HBA”) and a first FC switch and the second network element is another E port of a second FC switch.

6. The method of claim 5 , wherein the loopback test is performed on the data path.

7. The method of claim 5 , wherein the loopback test is performed on the control path, and frames of the loopback test are looped back at an FC-2 layer of the second network element.

8. The method of claim 1 , wherein the issue comprises at least one of unresponsive driver software, packet descriptor memory corruption, data structure corruption, FC driver memory leaks in an I/O path, large buffer transfer/receive processing hitting boundary conditions, and frame Direct Memory Access (“DMA”) memory corrupting frames due to handling a sudden I/O burst.

9. The method of claim 1 , wherein the issue comprises at least one of unresponsive driver software, packet descriptor memory corruption, data structure corruption, FC driver memory leaks in an I/O path, large buffer transfer/receive processing hitting boundary conditions, and frame Direct Memory Access (“DMA”) memory corrupting frames due to handling a sudden I/O burst.

10. The method of claim 1 further comprising:
determining a latency by comparing a first timestamp of a frame of the loopback test corresponding to a time the frame was sent to the second network element with a second timestamp of the frame corresponding to another time the frame was received back from the second network element.

11. One or more non-transitory tangible media that includes code for execution and when executed by a processor is operable to perform operations comprising:
configuring a first network element of a fibre channel (“FC”) network as a generator element, the generator element configured to reject a login request and force a second network element to operate as a reflector element that negotiates diagnostic mode parameters with the generator element when the generator element employs a link diagnostic protocol, the first network element and the second network element connected via a link;
determining diagnostic capabilities of the first network element and the second network element via a diagnostic phase, wherein one or more supported loopback tests are identified;
identifying the farthest loopback of the supported loopbacks;
performing the one or more supported loopback tests on a data path or a control path; and
exposing an issue on the data path or the control path between the first network element and the second network element based on a loopback test of the one or more supported loopback tests.

12. The media of claim 11 , wherein the first network element is an F port of an FC switch and the second network element is an N port of a host bus adapter (“HBA”) and wherein frames of the loopback test are looped back at an FC driver of the second network element.

13. The media of claim 11 , wherein the first network element is an E port of one of a host bus adapter (“HBA”) and a first FC switch and the second network element is another E port of a second FC switch and wherein the loopback test is performed on the data path.

14. The media of claim 11 , wherein the first network element is an E port of one of a host bus adapter (“HBA”) and a first FC switch and the second network element is another E port of a second FC switch and wherein the loopback test is performed on the control path, and frames of the loopback test are looped back at an FC-2 layer of the second network element.

15. The media of claim 11 , wherein the operations include determining a latency by comparing a first timestamp of a frame of the loopback test corresponding to a time the frame was sent to the second network element with a second timestamp of the frame corresponding to another time the frame was received back from the second network element.

16. An apparatus comprising:
a memory element configured to store data; and
a processor operable to execute instructions associated with the data,
the apparatus configured for:
configuring a first network element of a fibre channel (“FC”) network as a generator element, the generator element configured to reject a login request and force a second network element to operate as a reflector element that negotiates diagnostic mode parameters with the generator element when the generator element employs a link diagnostic protocol, the first network element and the second network element connected via a link;
determining diagnostic capabilities of the first network element and the second network element via a diagnostic phase, wherein one or more supported loopback tests are identified;
identifying the farthest loopback of the supported loopbacks;
performing the one or more supported loopback tests on a data path or a control path; and
exposing an issue on the data path or the control path between the first network element and the second network element based on a loopback test of the one or more supported loopback tests.

17. The apparatus of claim 16 , wherein the first network element is an F port of an FC switch and the second network element is an N port of a host bus adapter (“HBA”) and wherein frames of the loopback test are looped back at an FC driver of the second network element.

18. The apparatus of claim 16 , wherein the first network element is an E port of one of a host bus adapter (“HBA”) and a first FC switch and the second network element is another E port of a second FC switch and wherein the loopback test is performed on the data path.

19. The apparatus of claim 16 , wherein the first network element is an E port of one of a host bus adapter (“HBA”) and a first FC switch and the second network element is another E port of a second FC switch and wherein the loopback test is performed on the control path, and frames of the loopback test are looped back at an FC-2 layer of the second network element.

20. The apparatus of claim 16 further configured for determining a latency by comparing a first timestamp of a frame of the loopback test correspondi

Assignees

• Cisco Tech Inc

Inventors

• Bharadwaj Harsha
• Venugopalan Nagendran

Classifications

• H04L43/0817 Primary

  by checking functioning · CPC title

• H04L43/0811

  by checking connectivity · CPC title

• H04L43/50

  Testing arrangements · CPC title

• H04L1/243

  at the transmitter, using a loop-back · CPC title

• H04L43/14

  using software, i.e. software packages (network security related monitoring H04L63/1408) · CPC title