Description

This article explains the meaning for the syslog message:

PLL Error:LMK04808_MISC_LD

Symptoms

PLL errors are seen for various FPC components in the message logs: 

fpc1 PLL Error:LMK04808_MISC_LD
fpc1 PLL Error:LMK04906_WAN_LD
fpc1 PLL Error:LMK04906_FABRIC_LD
fpc1 PLL Error:LMK04808_MISC_LOS


FPC can either go offline or stuck in a boot loop.

Solution

PLL stands for Phase-Locked Look. This is used to synchronize clock signals between the RE and the FPC.

These error messages indicate an error with the PLL component, which in most cases will cause the FPC to go offline.

  1. Restart the FPC using offline / online sequence: 

    request chassis fpc offline slot x    ## replace x with FPC slot number

  2. Wait for the FPC to go offline and use ' show chassis fpc x detail' to verify.

    request chassis fpc online slot x


In some cases, rebooting the FPC may not resolve the issue. If so, try a physical reseat of the FPC. Most importantly, procure either a spare from inventory or through JTAC. As in most, cases these errors indicate a permanent hardware failure of the FPC.

Additional commands for collecting from FPC shell if it is online while these errors occur: 

  • start shell pfe network fpcx    ## replace x with FPC slot number
  • show syslog message
  • show cmerror module brief      ## this command shows the active PLL errors for the FPC