Description

The article describes the meaning of PPE Traps in Syslog and also suggests a resolution to overcome this error.

Symptoms

Error Log: 

Jun 23 13:18:17.598 2020  fpc1 PPE Thread Timeout Trap: Count 3395627, PC 38,     0x0038:  entry_ktree_nh
Jun 23 13:18:17.712 2020  fpc1 PPE PPE HW Fault Trap: Count 1, PC 52,     0x0052:  ipv4_input_verify_checksum
Jun 23 13:18:17.830 2020  fpc1 PPE Thread Timeout Trap: Count 3394709, PC 4f,     0x004f:  KTOpc7_trap​

Jun 23 13:18:19.574 2020  fpc1 PPE Thread Timeout Trap: Count 12176226, PC 3b0,     0x03b0:  ktree_nh_launch
Jun 23 13:18:19.574 2020  fpc1 PPE Thread Timeout Trap: Count 12180347, PC 6075,     0x6075:  KTree_Term_With_Mult_Result_2
Jun 23 13:18:19.577 2020  fpc1 PPE Thread Timeout Trap: Count 3395630, PC 4f,     0x004f:  KTOpc7_trap
Jun 23 13:18:19.667 2020  fpc1 PPE PPE HW Fault Trap: Count 1, PC 52,     0x0052:  ipv4_input_verify_checksum
Jun 23 13:18:19.785 2020  fpc1 PPE Thread Timeout Trap: Count 3394719, PC 6075,     0x6075:  KTree_Term_With_Mult_Result_2

Solution

Check the FPC type:

user@host> show chassis hardware detail no-forwarding
Hardware inventory:
Item             Version  Part number  Serial number     Description
Chassis                                xx                MX480
<snip>
FPC 1            REV 13   750-062865   xx                MPC4E 3D 32XGE

Check FPC status:

user@host> show chassis fpc detail
Slot 1 information:
  State                                 Online
  Temperature                        31
  Total CPU DRAM                   2048 MB
  Total RLDRAM                     1036 MB
  Total DDR DRAM                   11264 MB
  Start time:                           2019-02-14 15:11:01 CET
  Uptime:                               494 days, 21 hours, 24 minutes, 17 seconds
  Max Power Consumption             584 Watts

Although the error is transient in nature, packet hitting this error may be dropped. This PPE syslog is because of LMEM data errors that could be caused due to transient memory parity issues. 

Jun 23 13:18:19.577 2020 fpc1 PPE Thread Timeout Trap: Count 3395630, PC 4f, 0x004f: KTOpc7_trap 
Jun 23 13:18:19.667 2020  fpc1 PPE PPE HW Fault Trap: Count 1, PC 52,     0x0052:  ipv4_input_verify_checksum

From the above syslog, the below are the interpretations:

<ipv4_input_verify_checksum> : indicates that a trap occurred when the microcode attempted to interpret data past the end of the packet.

<HW Fault Trap: Count #> : The amount of traffic drop can be found in the ‘count’ of the HW fault trap message.

 

You may ignore this message in case you are not witnessing packet drops. In order to prevent this error from occurring, a restart of the FPC needs to be performed.

Restart FPC: 

user@host> request chassis fpc (offline | online | restart) slot slot-number

Here,

user@host> request chassis fpc restart slot 1

      OR

Reseat the FPC manually:

You must unplug the FPC from its slot and plug it back in on the chassis. This will help power re-initiation on the FRU and clear all possible transient issues.

If the above does not help in resolving the error, this could be a hardware fault that might need a replacement. Please contact JTAC for further investigation.