Methods, apparatus, and systems for implementing in Network Interface Controller (NIC) flow switching. Switching operations are effected via hardware-based forwarding mechanisms in apparatus such as NICs in a manner that does not employ use of computer system processor resources and is transparent to operating systems hosted by such computer systems. The forwarding mechanisms are configured to move or copy Media Access Control (MAC) frame data between receive (Rx) and transmit (Tx) queues associated with different NIC ports that may be on the same NIC or separate NICs. The hardware-based switching operations effect forwarding of MAC frames between NIC ports using memory operations, thus reducing external network traffic, internal interconnect traffic, and processor workload associated with packet processing.