Description

The "PRB_EVENERR or PRB_ODDERR" message is likely caused caused by a transient hardware issue in the unload block of EACHIP or XLCHIP.

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 - Master Index of Articles for Troubleshooting PFE ASIC Syslog Events [juniper.net] .

Symptoms

When a "PRB_EVENERR or PRB_ODDERR" event occurs messages similar of the following are reported:

EACHIP:

Aug 28 16:07:45.602 router: %PFE-3: fpc8 EA[0:0].unload[1]: PRB_EVENERR 01
Aug 28 16:07:46.601 router: %PFE-3: fpc8 EA[0:0].unload[1]: PRB_ODDERR 03

XLCHIP:

Sep 6 16:31:14.183 router : %PFE-3: fpc10 XL[0:0].unload[0]: PRB_EVENERR 07
Sep 6 16:31:14.200 router : %PFE-3: fpc10 XL[0:0].unload[0]: PRB_ODDERR 02

The following syslog entries upon unload parity errors are reported:

Aug 28 10:42:00.894 router : %PFE-3: fpc10 XMCHIP(1): XMCHIP(1): LI0: Received a parcel from the HSL2 interface with EOPE or
Aug 28 16:07:45.598 router : %PFE-3: fpc8 MQSS(0): LI-1: Received a parcel from the HSL2 interface with EOPE

As a post effect, fabric-self ping blackholing will trigger an alarm upon failure on the fabric side. Host-loopback wedge detection will trigger an alarm if the WAN side is affected. HSL2 with EOPE means the parcel received from the high-speed link was marked with “end of parcel with error” bit. This is not an indication that the high-speed link is not stable, but rather the unload block had marked the parcel with an error-bit.

Indications:

  • PFE wedge will be detected and traffic forwarding is compromised

  • Alarm will be raised

 

Solution

This error is caused by a transient SRAM parity error. The Unload block is processed once all lookup is finished and the parcel is about to get sent to the Center Chip XMCHIP or EACHIP. In all cases, these parity errors cause a wedge  for the corresponding XMCHIP or EACHIP

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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.

    {SYSLOGSERVICENOWTOKEN.EN_US}

    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
    exit

  2. Analyze the show command output.

    In the 'show log messages', review the events that occurred at or just before the appearance of the "PRB_EVENERR or PRB_ODDERR" message. Frequently these events help identify the cause.

This article is indexed in  KB31893 - Primary Index of Articles for Troubleshooting PFE ASIC Syslog Events [juniper.net] ; tag EACHIPTSG XLCHIPTSG


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

10/8/2024 : dconejomora - adding MX960 in the KB categories, changing visibility to Internal, Partner and Customer