What we have:
two systems with Microtik v3.11 and Atheros cards, 2km LOS, ADSL link between them
What we need:
need half duplex link like nstreme-dual but with ethernet card as backchannel. Radio card on point A only transmit packets, radio card on point B only receive packets, backchannel via ADSL.
Asymmetric routing - it’s IP routing. In that case card B will send frame reply to received frames.
Maybe put card B in promisc mode (receive all data that is in channel) with IP+MAC filtering?
NStreme Dual provides a “full-duplex” link, not a half duplex link.
You could set up asymmetric routing as others have suggested, but you won’t be using NStreme dual to do it, and you will still be sending radio packets in both directions to make it work.
Nice idea, but it went out of style with 1-way satellite.