Description

root-re0> show chassis alarms

1 alarms currently active

Alarm time Class Description

2026-01-01 02:41:16 UTC Major FPC 0 Major Errors

Symptoms

FPC Major error observed due to XQSS_CMERROR_DSTAT_INT_REG_DROP0_VOTE_OVRN post member link of an AE interface flaps, resulting in traffic impact on the affected PFE.

The ASIC queues on most of Trio ASICS never operate in Back pressure mode but in the Drop mode. Because they operate in Drop mode, it is not possible for the queue to participate in back-pressure compute logic. 

However, since we are seeing a Back pressure specific alarm being raised for a queue that should be supposedly be in Drop mode.


Below logs and alarms observed during the event.

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router-re0 fpc0 cmerror_set_error: Module: XQSS(1), pfe id:1, error_id:0x23006d reason:XQ-SS[1]: Vote counter overrun error in Drop engine 0 for wan qnum 89, vote_ptr 24

router-re0-fpc0 ytchip-xqss[17059]: [Info] CDA: XQSS: 1 setError success; xqssModuleHandleId:12 error code: 0x2293869 : XQ-SS[1]: Vote counter overrun error in Drop engine 0 for wan qnum 89, vote_ptr 24

router-re0-fpc0 resiliencyd[14657]: CMError: /fpc/0/platformd/0/cm/0/xqss/1/XQSS_CMERROR_DSTAT_INT_REG_DROP0_VOTE_OVRN (0x23006d), scope: pfe, category: functional, severity: major, module: XQSS(1), type: XQSS DSTAT DROP0 VOTE overrun, oc_category: default

router-re0-fpc0 resiliencyd[14657]: Performing action get-state for error /fpc/0/platformd/0/cm/0/xqss/1/XQSS_CMERROR_DSTAT_INT_REG_DROP0_VOTE_OVRN (0x23006d) in module: XQSS(1) with scope: pfe category: functional level: major, oc_category: default

router-re0-fpc0 root[29285]: pfe_get_state.sh : Running PFE get state script

router-re0-fpc0 root[29293]: pfe_get_state.sh : PFE AFT Get state started - Module: (xqss), Error: (XQSS_CMERROR_DSTAT_INT_REG_DROP0_VOTE_OVRN), Date/Time: (18/05/2026 19:38:33)

router-re0-fpc0 resiliencyd[14657]: Performing action cmalarm for error /fpc/0/platformd/0/cm/0/xqss/1/XQSS_CMERROR_DSTAT_INT_REG_DROP0_VOTE_OVRN (0x23006d) in module: XQSS(1) with scope: pfe category: functional level: major, oc_category: default

router-re0-fpc0 resiliencyd[14657]: EMF_EVO_ALARM_SET: Alarm set: FPC color=red, class=CHASSIS, reason=FPC 0 Major Errors

router-re0-fpc0 resiliencyd[14657]: Performing action disable-pfe for error /fpc/0/platformd/0/cm/0/xqss/1/XQSS_CMERROR_DSTAT_INT_REG_DROP0_VOTE_OVRN (0x23006d) in module: XQSS(1) with scope: pfe category: functional level: major, oc_category: default


router-re0> show chassis alarms

1 alarms currently active

Alarm time Class Description

2026-01-01 02:41:16 UTC Major FPC 0 Major Errors


user@router-fpc0:pfe> show cmerror module fpc 0 | grep XQSS_CMERROR_DSTAT_INT_REG_DROP0_VOTE_OVRN 

         0x23006d   0  Major   1    0    0    0    0          XQSS_CMERROR_DSTAT_INT_REG_DROP0_VOTE_OVRN

         0x23006d   1  Major   1    0    0    0    0          XQSS_CMERROR_DSTAT_INT_REG_DROP0_VOTE_OVRN

         0x23006d   2  Major   1    0    0    0    0          XQSS_CMERROR_DSTAT_INT_REG_DROP0_VOTE_OVRN

         0x23006d   3  Major   1    0    0    0    0          XQSS_CMERROR_DSTAT_INT_REG_DROP0_VOTE_OVRN

Solution

As a workaround:  Restart the FPC to resolve the issue temporary.

Permanent fix :

We have reduced the severity of the back pressure specific alarms to minor to rule out false positives.

user@router-fpc0:pfe> show cmerror module fpc 0 | grep XQSS_CMERROR_DSTAT_INT_REG_DROP0_VOTE_OVRN 

         0x23006d   2  Minor   1    0    0    0    0          XQSS_CMERROR_DSTAT_INT_REG_DROP0_VOTE_OVRN

         0x23006d   3  Minor   1    0    0    0    0          XQSS_CMERROR_DSTAT_INT_REG_DROP0_VOTE_OVRN

         0x23006d   0  Minor   1    0    0    0    0          XQSS_CMERROR_DSTAT_INT_REG_DROP0_VOTE_OVRN

         0x23006d   1  Minor   1    0    0    0    0          XQSS_CMERROR_DSTAT_INT_REG_DROP0_VOTE_OVRN


Issue has been fixed in below releases :

evo:25.4R2-EVO 

evo:26.2R2-EVO 

evo:26.3R1-EVO 

junos:23.2R2-S8 

junos:24.2R2-S6 

junos:25.2R2-S2 

junos:25.4R2 

junos:26.2R1 

junos:26.2R2 

junos:26.3R1

Modification History

2026-07-06 : Article Created