The "XMCHIP(2): XMCHIP(2): EPM0: Packet delimiter violation detected - Queue 32" message reports a transient hardware issue.

This is a Troubleshooting article for a PFE ASIC Syslog Event.

Along with a "XMCHIP(0): EPM0: Packet delimiter violation detected - Queue 0", the following errors are reported:

• Single occurrence of syslog, not seen with other events, indicates a one time hardware error. 
• Multiple continuous occurrences with "EPM_PROTECT: Detected: Parity error for main data buffer" indicate persistent underlying issues and could impact the traffic.
• Traffic impact or permanent impact of packet forwarding depending on the number of times syslog entry.

EPM is the Egress Priority-Flow-Control Manager Block. Normally, two blocks EPM0 and EPM1 to the server WAN interfaces of the PFE. Single parity error does not impact packet forwarding. However, multiple parity errors in conjunction with other EPM errors may impact the transient traffic.

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 pfe network <fpc#>
   show cmerror module
   show nvram
   show syslog messages
   exit

Analyze the show command output.

In the 'show log messages', review the events that occurred at or just before the appearance of the "Enqueue upon free pool empty" message. These events frequently help identify the cause.

Recommended Action

• No RMA is required.
• Restart the MPC and monitor the errors.
• Contact your technical support representative if the issue is seen after restarting the FPC.

2022-11-15 Update recommended action.
2020-10-28: Fixed typo in Solution item 1 (start shell network pfe <fpc#> To: start shell pfe network <fpc#> )