Description

The "KMB parity error" message reports a transient hardware or software issue.


This is a Troubleshooting Article for a PFE ASIC Syslog Event.
To view other documented syslog events related to XMCHIP, XLCHIP, MQCHIP, LUCHIP, EACHIP, and PECHIP, see KB31893 - Master Index of Articles for Troubleshooting PFE ASIC Syslog Events [juniper.net] .

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Symptoms

When a "KMB parity error" event occurs, a message similar to the following is reported:
Jan 20 19:22:11.397 router0 fpc10 LUCHIP(0) PPE_5 Errors KMB[205] parity error

Indications :
  1. Single occurrence, not seen with other events, indicates one time hardware error. Multiple continuous occurrences indicate persistent underlying hardware issues.
  2. No service impact in most of the cases. In some cases, there can be an affect on packet forwarding.
  3. Temporary congestion can be noticed which will eventually get cleared-up.

 

Solution

The cause is due to either hardware or software issues resulting in a parity error in the LUCHIP KMB memory. The exact root cause will have to be determined by further examining the syslog and FPC log data.

If the issue is hardware, these are transient hardware errors. Transient parity errors in PPE(KMA/KMB) memory are causing these errors. Control plane driver repairs these errors eventually. These errors are very location specific in terms of symptoms. At some memory location these can wedge the line card. At other times, it might cause temporary congestion and clear up.

 

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Perform these steps to determine the cause and resolve the problem (if any).  Continue through each step until the problem is resolved.

  1. Collect the show command output.

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    Capture the output to a file (in case you have to open a technical support case). To do this, configure each SSH client/terminal emulator to log your session.

    show log messages
    show log chassisd
    start shell network pfe <fpc#>
    show nvram
    show syslog messages
    exit

  2. Analyze the show command output.

    In the 'show log messages', review the events that occurred at or just before the appearance of the "KMB parity error" message. Frequently these events help identify the cause.

If  the errors are reported for same memory location, shutdown the FPC using power off commands.
To power off an FPC :
set chassis fpc <slot> power off
commit
 

This article is indexed in KB31893 - Primary Index of Articles for Troubleshooting PFE ASIC Syslog Events [juniper.net] ; tag LUCHIPTSG.


Tip: When looking at an event in the logs, it is important to focus on the first error message in a collection of syslog messages. The first error message is usually the cause of all the follow-on error messages. The follow-on collateral damage error messages can be ignored.

 

Modification History

2022-10-21 KB marked for public - missing from previous review
2019-10-14: Article reviewed for accuracy; no changes required.