I jst found out that this problem only happens to ARP pakcets. If it
sends out a Unicast response to a ARP request, the non unicast counters
increments not the unicast counter. If it sends ARP request, the
counter updated correctly.

ask wrote:
> I just found strange problem with my END.
> My END update counters. When I run ifShow, receive direction counters
> look right, but transmit counter do not. I took out the transmit
> direction counter update code totally. Then it seems the transmit
> counter updates by itself (may by update by MUX service?). Also when it
> updates, it does not count broadcast; but count every unicast as
> NON-Uicast packet. The unicast and non-unicast packets are ARP packets.
> For the moment, I am not ready to deal with other packets in my
> simulation environment yet.
>
> Thanks,