This article explains the reason for the occurrence of FPC major alarm with "PE Error Code: 0x2101aa" , the troubleshooting steps and how to clear the alarm.
"PE Error Code: 0x2101aa"
Active alarms:
user@host> show chassis alarms 2 alarms currently active Alarm time Class Description 2019-10-19 09:52:22 UTC Major FPC x Major Errors - PE Error code: 0x2101aa 2019-10-19 09:52:22 UTC Major FPC y Major Errors - PE Error code: 0x2101aa
Error:
Oct 19 09:52:22.856 alarmd[5474]: %DAEMON-4: Alarm set: FPC color=RED, class=CHASSIS, reason=FPC 6 Major Errors - PE Error code: 0x2101aa Oct 19 09:52:22.856 craftd[5475]: %DAEMON-4: Receive FX craftd set alarm message: color: 1 class: 100 object: 104 slot: 6 silent: 0 short_reason=FPC 6 Major Errors long_reason=FPC 6 Major Errors - PE Error code: 0x2101aa id=150996584 reason=150994944
The Error Messages just before the alarm was triggered:
Oct 19 09:52:22.000 %USER-3: fpc6 fpc6 dcpfe: Cmerror Op Set: PE Chip: PE2[2]: EPW: crc error#012 Oct 19 09:52:22.807 %PFE-3: fpc6 Cmerror Op Set: PE Chip: PE2[2]: EPW: crc error Oct 19 09:52:22.856 alarmd[5474]: %DAEMON-4: Alarm set: FPC color=RED, class=CHASSIS, reason=FPC 6 Major Errors - PE Error code: 0x2101aa Oct 19 09:52:22.856 craftd[5475]: %DAEMON-4: Receive FX craftd set alarm message: color: 1 class: 100 object: 104 slot: 6 silent: 0 short_reason=FPC 6 Major Errors long_reason=FPC 6 Major Errors - PE Error code: 0x2101aa id=150996584 reason=150994944 Oct 19 09:52:22.856 craftd[5475]: %DAEMON-4: Major alarm set, FPC 6 Major Errors - PE Error code: 0x2101aa Oct 19 09:52:43.000 %USER-3: fpc6 fpc6 dcpfe: Cmerror Op Set: PE Chip: PE2[2]: EPW: crc error#012 Oct 19 09:52:43.232 %PFE-3: fpc6 Cmerror Op Set: PE Chip: PE2[2]: EPW: crc error Oct 19 09:53:49.000 %USER-3: fpc6 fpc6 dcpfe: Cmerror Op Set: PE Chip: PE2[2]: EPW: crc error#012
EPW is the egress packet write block within the PE chip. CRC check will be performed on every packet in the EPW block on the egress path. If the check fails, then the CRC error will be reported. The “CRC errors” are caused when FPC/DPC or Control Board (CB) might not be allowing transit traffic to be handled as expected, thereby causing an incorrect CRC value to be sent with traffic going through the switch fabric. Although the log message refers to a Flexible PIC Concentrator (FPC), such a reference does not necessarily mean that part is faulty, but only that an issue was detected in the received traffic.
Indications:
The error code 0x2101aa corresponds to the Egress Packet Writer CRC error. The Egress Packet Writer is the block within PE chip which receives the packets from the Fabric Input block, checks the CRC, BER, and writes the packet to the memory buffer. You may also see BER errors along with CRC errors in certain cases. BER is reported as and when bit errors are detected. This could be due to a transient issue with the transit packet. Example Logs:
Feb 20 20:55:41.907 fpc6 CCL: 1 CRC errors seen on link PE2-Avg-28nm-link-9-17 Feb 21 03:04:03.213 fpc6 CCL: 2 BER errors seen on link PE2-Avg-28nm-link-9-17
Ideally, the alarms will clear on their own if it occurs infrequently but the errors will remain in the logs. In case the errors frequently occur and alarms are triggered and getting cleared frequently, you may consider restarting the FPC.
Restart FPC:
user@host> request chassis fpc (offline | online | restart) slot slot-number
user@host> request chassis fpc restart slot 6
If the error still persists post restart and alarms do not clear and contact JTAC Support . This might need detailed investigation to rule out possibility of permanent hardware error due to issue on the chip level.