Once two devices associate, you must send data across the powerline in both direction so that each device can compute a TX and RX PHY rate. One method is to use the efsu program that comes with the Toolkit. The program is designed to send free-form Ethernet frames for test and debug purposes but we can also use it to send lots of junk frames in either direction.

FRAME=frame.hex
COUNT=1000
efsu -i ${NIC1} -hd ${MAC2} ${FRAME} -l ${COUNT}
efsu -i ${NIC2} -hd ${MAC1} ${FRAME} -l ${COUNT}
efsu -i ${NIC1} -hd ${MAC2} ${FRAME} -l ${COUNT}
efsu -i ${NIC2} -hd ${MAC1} ${FRAME} -l ${COUNT}

The example above uses efsu to send the generic Ethernet frame stored in file frame.hex between the two Ethernet interfaces NIC1 and NIC2 (-i). In this example, NIC1 and NIC2 are both installed in the host. We have efsu insert the host source address in the OSA field (-h) and destination address in the ODA field (-d) of each frame as it is sent. The entire operation sends the same frame 1000 times (-l) in each direction, twice.

Other methods of generating bi-directional traffic can be used but this method is simple, needs nothing other than the toolkit programs and permits easy synchronization. Program efsu is designed to send custom Etherenet frames, not measure or control data rates, but the toolkit includes open source program ttcp which is designed to measure and control data rates.