A free-space optical (FSO) transceiver can include a transmission protocol configured to encapsulate outgoing network packets in by employing a reliable ordered protocol that relies on retransmission of lost data to form outgoing encapsulated packets. The transmission protocol controller can be configured to employ a congestion algorithm that optimizes throughput over a lossy link. The FSO transceiver can also include a transmitter configured to provide an output optical signal corresponding to the outgoing encapsulated packets over an FSO link.