This counts every packet the card attempted to transmit, including ones that were ultimately discarded or never actually sent, not just successfully transmitted packets. Because failed and discarded attempts are folded into this counter, an admin can't use it alone to gauge actual successful throughput; it must be compared against a discard counter for that card to separate genuine output volume from queue drops and errors inflating this total. For example, a card showing high cardOutPkts growth but flat cardOutOctets growth would suggest many of those transmit attempts are small discarded packets rather than real forwarded traffic.