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Syslog message: HMM.*Lane.*TX RLL event 



Article ID: KB32119 KB Last Updated: 12 Oct 2021Version: 2.0

The "TX RLL event" message reports Run Length Limit (RLL) event on a Hybrid Memory Link.

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 "TX RLL event" event occurs, a message similar to the following is reported:

Aug 26 23:02:38 router-re0 fpc10 HMM[EA[2:0]-chan-rx1-sc0], Lane 5, TX RLL event seen
Aug 26 23:02:39 router-re0 fpc10 eachip_hmcif_rx_link_intr_handler(7803): EA[2:0]: HMCIF Rx: Link0: A response packet with a benign WARNING state is received from HMC - State: 0x20, Count 1


  • No operational impact with single occurrence
  • Multiple continuous occurrences indicates persistent underlying issue



This indicates a Run Length Limit event on scrambled links and Junos OS will automatically retry to recover. Successful recovery will be confirmed with the second debug message with State: values between 0x20 - 0x23.​

A response packet with a benign WARNING state is received from HMC - State: 0x20



Junos OS will attempt to recover automatically.

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 "TX RLL event seen" message. Frequently, these events help identify the cause.

  • No RMA needed
  • No further action is needed
  • If this event does occur frequently, please contact your technical support representative

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

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.


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