This article provides diagnosis and troubleshooting for hardware-related issues specifically targeting the ASIC errors in the TCAM on FPCs that have a great influence on network reliability and performance.

The below could be observed in the syslog messages followed by a FPC crash.

[Feb 26 01:03:00.312 LOG: Debug] precl_cmalarm_info_create: idx 1 for fpc X pic y aisc-id 95 asic-inst 0 pg 0 from config idx 1 error 0x340003 level 1 threshold 1 PRECL_CMERROR_TCAM_COMMAND_FAIL

[Feb 26 01:03:00.312 LOG: Debug] precl_cmalarm_info_create: idx 1 for fpc X pic y aisc-id 95 asic-inst 0 pg 0 from config idx 2 error 0x340004 level 1 threshold 1 PRECL_CMERROR_TCAM_PARITY_FAIL

The log provided indicate hardware-related errors, specifically related to issues with the ASIC on FPC X, PIC y , and more specifically to the TCAM.

A TCAM command fail suggests that a specific command or instruction could not be processed correctly in the TCAM. This could result in misbehaviour in packet forwarding or routing.

Parity failures in TCAM indicate that there is a memory error, likely corruption, or an issue with the integrity of the data stored in the TCAM.

The below could be the possible causes:

• Hardware Failure: The most likely cause for these errors is a hardware failure in the FPC, PIC, or ASIC. 
• Corrupted TCAM Memory: The TCAM memory in the ASIC might be corrupted, which could lead to erratic behavior and network issues, such as traffic loss, misrouting, or slow performance.
• Environmental Issues: Overheating or other environmental factors could affect hardware performance, leading to errors in the memory or ASIC.
• Resource Exhaustion: If the TCAM is under heavy load (e.g., too many ACLs or forwarding entries), this could trigger errors as well.

To resolve the issue, need to follow the below steps:

a. Check the health of the FPC/PIC.

           show chassis fpc

show chassis pic

show chassis environment

b. Examine system logs for additional errors. Check the below log:

show log messages

c. Check TCAM Utilisation:

Ensure that the TCAM is not being overloaded with too many entries, such as ACLs, firewall filters, or routing entries. If the TCAM is full, it can cause errors like the ones you are seeing.

c. If the issue persists, consider replacing the FPC or PIC as it could be related to a defective component.

Contact Juniper Support for further diagnosis or to replace faulty hardware.