Symptom
An ISR 4K router may repeatedly see a NIM module reload with "NGO control packet loss" syslogs similar to the following:
%IOMD-3-MODULE_MESSAGE: R0/0: iomd: NIM-XXXXX[0/X] NGIO control packet loss detected: module reloading
%SPA_OIR-6-OFFLINECARD: SPA (NIM-XXXXX) offline in subslot 0/X
The following event will also be seen in the kernel dmesg log of the router's RP / control plane. The dmesg can be obtained via tracelogs or by manually logging into the shell via "request platform software system shell rp active" and running the command "dmesg".
NETDEV WATCHDOG: eth3 (igb): transmit queue 3 timed out
Queue 3 is the igb driver that handles control packets, and if the transmit queue is timing out, this is another sign of the issue.
Conditions
This can be seen with some models of NGIO modules, such as a "NIM-1GE-CU-SFP".
Workaround
Reloading the router may temporarily fix the issue.
Further Problem Description
Random software-triggered resets of the NGIO module are caused by a condition between internal front panel channels.
