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Syslog message: XMCHIP.*WO.*Packet error - Error Packets



Article ID: KB31737 KB Last Updated: 19 Nov 2021Version: 5.0

The "WO Packet error" message reports a transient hardware 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 - Index of Articles for Troubleshooting PFE ASIC Syslog Events.



When a "WO Packet error" event occurs, a message similar to the following is reported:

Sep 5 15:03:54 router0 : %PFE-3: fpc2 XMCHIP(1): WO0: Packet error - Error Packets 1, Stream 2
5 15:03:55 router0 : %PFE-3: fpc2 XMCHIP(1):‚Äč WO0: Protect: Parity error for Output buffer data


  • Single occurrence of syslog, not seen with other events, indicates a one time hardware error. Multiple continuous occurrences indicate persistent underlying issues.
  • Traffic impact or permanent impact on packet forwarding may happen if errors are seen repeatedly.



The is due to an internal hardware issue in processing the specific packet on the XMCHIP.  A single occurrence of the message indicates a one-time error condition. 


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.

    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

  2. Analyze the show command output.

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

  • No RMA required.
  • FPC restart during Maintenance Window should clear this error.
  • Contact your technical support representative if the issue is seen after a FPC restart. 

This article is indexed in KB31893 - Primary Index of Articles for Troubleshooting PFE ASIC Syslog Events; tag XMCHIPTSG

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:
2019-10-14: Article reviewed for accuracy; no changes required.
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