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Syslog message: EA.*HMCIO TX: AFIFO overflow event detected in Channel



Article ID: KB32291 KB Last Updated: 11 Oct 2021Version: 3.0

The "HMCIO TX: AFIFO overflow event" messages is caused due to transient FIFO overflow condition.

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 HMCIO TX: AFIFO overflow event detected in Channel event occurs, a message similar to the following is reported:

Nov 3 15:00:59.279 router : %PFE-7: fpc8 Cmerror: Draining ASIC error message queue
Nov 3 15:00:59.279 router : %PFE-7: fpc8 cmerror_process_queue: module = HMM:EA[0:0]
Nov 3 15:00:59.279 router : %PFE-7: fpc8 Cmerror: processing the task op_type 1 for level 1 level_count 1 occur_count 1 clear_count 0 level_threshold 1 level_action 0x4 item errid 2490370 item_threshold 1 item_count 0 item_sub_err_state 0 sub_item errid 0 sub_item_state 0 item_times
Nov 3 15:00:59.279 router : %PFE-7: fpc8 Cmerror: Level 1 count increment 2 occur_count 2 clear_count 0
Nov 3 15:00:59.280 router : %PFE-6: fpc8 Error: /pfe/0/cm/0/HMM:EA[0:0]/0/HMCIO_LANE_TX_AFIFO_OVERFLOW (0x260002), severity: major, module: HMM:EA[0:0] , type: HMCIO_TX_LANE_AFIFO_OVERFLOW
Nov 3 15:00:59.280 router : %PFE-7: fpc8 Cmerror: Level 1 count 2 (occur_count 2 clear_count 0)crossed threshold 1 action 0x4
Nov 3 15:00:59.280 router : %PFE-7: fpc8 cmerror_take_action_helper: performing action 4 for level 1 err_id /pfe/0/cm/0/HMM:EA[0:0]/0/HMCIO_LANE_TX_AFIFO_OVERFLOW (0x260002) module id 15
Nov 3 15:00:59.280 router : %PFE-3: fpc8 Cmerror Op Set: HMM:EA[0:0] : EA[0:0]: HMCIO TX: AFIFO overflow event detected in Channel: EA[0:0]-chan-rx0-sc0, Lane 0
Nov 3 15:00:59.280 router chassisd[59932]: %DAEMON-3: ASIC Error detected errorno 0x00260002 Restart action performed
Nov 3 15:00:59.280 router chassisd[59932]: %DAEMON-5-CHASSISD_FRU_OFFLINE_NOTICE: Taking FPC 8 offline: FPC reset by error manager


  • Permanent PFE forwarding impact and FPC restarts automatically due to CMERROR severity Fatal
  • Alarm will be raised
  • In Junos 17.3R1 or higher, disable-pfe action will be invoked instead of reset-fpc

This indicates that the Tx AFIFO before the serdes has detected an overflow condition which is a fatal error condition from which it cannot recover without a reset.


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 "HMCIO TX: AFIFO overflow event" message. Frequently, these events help identify the cause.

  • RMA is only required if after the FPC restart, the same error condition occurs again
  • If the FPC is not passing the internal Power on Self Test (POST) and reports "Error initializing PFE asics", hardware replacements need to be initiated.
  • In Junos OS 17.3R1 or higher, the default action will be disable-pfe instead of FPC restart, which is changed within PR1186421
  • Contact your technical support representative immediately

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.


Modification History:

Note: KB Team - All changes to this article must be approved by the AI-Scripts Review team ( before re-publishing.

AI-Scripts history:       (Updated by AI-Scripts team only)
Date KB Article Version AI-Scripts PR (optional) Notes
1/10/2018 1.0 1332236 New Syslog KB

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