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FN-2018-424, VDX 6940 ASIC Interrupt Errors

  • Article Type:
  • Field Notice
  • Article Number:
  • 000035953
  • Last Modified:
  • 10/24/2018

Notice Summary

 
Continuous ASIC errors can cause an ASIC chip fault condition in VDX6940 with NOS version with 6.0.2b, 7.0.1a or earlier versions.
The ASIC errors will impact a VDX switches ability to process VCS initialization packets on ISLs and can cause a switch to lose ISL links, if the ISL transitions during the presence of ASIC errors. This can lead to a disconnection from the VCS fabric.

Customers running the affected NOS versions are strongly recommended to upgrade as soon as possible to mitigate the potential loss of services.

Background

 
Switch may see ASIC error interrupts due to memory parity errors or SFP link issues. When these interrupts are processed and handled successfully it will not cause any impact to the switch.

However, when the interrupts are logged to the switch at a high rate and the switch is reporting excessive interrupts, the ASIC errors will impact the VDX switches ability to process VCS initialization packets on ISLs.

Impact

 
VCS switch will be isolated from the fabric due to loss of ISL link(s), and it will not rejoin the fabric.

Products Affected

 
VDX6940-144S and VDX6940-36Q Family Products

Software Affected

 
NOS Software versions prior to 6.0.2c and 7.0.1b.

Fixed in: NOS 6.0.2c, 7.0.1b, 7.0.2, 7.1.0, and 7.2.0a3

Symptoms

 
Physical link between VDX switches show as “Up/Up” but the link does not become an ISL link. SupportSave indicates “Too many interrupts” in the Internal raslog as below:
2017/04/20-16:37:11:379641, [CBR2-5665], 271060/0, SW/0 | Active, ERROR, VDX6940-36Q, CHIP0: Too many interrupts (501) happened. 
The Global error cause is (0x40 0x0), Global normal cause is (0x0 0x0)., OID:0x43008080,
cbr2_intr.c, line: 1048, comp:insmod, ltime:2017/04/20-16:37:11:379438 
Note: As this is an internal RASLOG it will not appear on the console, use ‘errdumpall’, a root level command, to examine the RASLOG.

Workaround

 
The ASIC errors can be stopped by reloading the impacted VDX 6940. Once the switch is reloaded it will recover and process the ISL initialization packets as expected. However, the next time ASIC errors are generated due to certain conditions the defect will be triggered again.

Solution

 
The recommendation is to upgrade to NOS 7.0.2b Target Path, that includes the software fix for Defect 624394.
 
The same fix is also applied to NOS 7.0.1b and later versions, including all 7.1.0 & higher versions.

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