I have a similar issue.
One device has a qlen>0 on one interface. It varies between 30 and 70.
This is what the web says:
ifOutQLen (Common event)
The length of the output packet queue (in packets). This number should return to zero in a short amount of time. If it ends up being any non-zero value for any length of time, you should consider upgrading the interface to a faster technology, or full duplex (if not already enabled).
I have a feeling that the ifOutQLen values may be a direct result of the snmp polling that I'm doing. I will investigate further.
I wonder If you someone got any information related to the ifOutQLen I need to monitor how busy is the router in each interface and I am strolling with little documentation about that.
Any r help will be appreciated