Description

This KB enlists ways to troubleshoot the below error seen on the interfaces:-

1. Carrier transitions
2. Framing errors

Symptoms

A high count of carrier transition and framing errors will be seen on the interface:-

Physical interface: xe-1/0/18, Enabled, Physical link is Up
<truncated>
  Input errors:
    Errors: 0, Drops: 0, Framing errors: 34789, Runts: 0, Bucket drops: 0, Policed discards: 0, L3 incompletes: 0, L2 channel errors: 0, L2 mismatch timeouts: 0, FIFO errors: 0, Resource errors: 0
  Output errors:
    Carrier transitions: 9789, Errors: 0, Drops: 0, Collisions: 0, Aged packets: 0, FIFO errors: 0, HS link CRC errors: 0, MTU errors: 0, Resource errors: 0, Bucket drops: 0


The above errors will be incremented as well with time.

Solution

  • Framing errors denote the Number of packets received with an invalid frame checksum (FCS).

  • Carrier transition denotes the Number of times that the interface has gone from down to up. This number does not normally increment quickly; increasing only when the cable is unplugged, the far-end system is powered down and then up, or another issue occurs. If the number of carrier transitions increments quickly (perhaps once every 10 seconds), the cable, far-end system, PIC  (Physical Interface Cards), or PIM (Physical Interface Module) is malfunctioning.


The below steps can be followed to troubleshoot these errors.

Step-1: The very first step is to clear interface statistics:-

> clear interface <interface-name> statistics
                              or
>clear interfaces statistics  [to clear statistics for all interfaces]

Step-2:-  Check if errors are incrementing by running the below commands multiple times:-

> show interfaces extensive <interface-name> | match "phy|desc|err|flap|last"  

or

> show interfaces extensive  | match "phy|desc|err|flap|last"

Step-3:-

  • Please change the cable and optics at the device end and check if the errors are incrementing. If errors are still increasing then if possible change cable and optics at the other end as well. The reason to perform this is that both carrier transition and framing errors can be because of issues at the remote end as well so by this step we can rule that out.

  • If the above step does not help then there are two possibilities, The first is that the interface slot on the juniper device might be having the issue and this can be transient as well. Transient error requires a reboot to clear. Reboot the device in a planned maintenance window and check if the errors stop incrementing.

  • Alternatively, if there are free ports on the device then u can move the affected port connection to other ports on the same device and check if the error is still seen. If errors are still seen then the other end needs to be investigated and if not then interfaces on QFX were faulty and we need to replace the device.


 

Modification History

2024-05-19 : Article Created

2025-04-14 : Updating the KB title