In order to do an injection test, first start Wireshark and the filter expression (wlan.bssid == <mac>) && !(wlan.fc.type_subtype == 0x08). This will ensure that we only see non-beacon packets for our lab network.

Now run the following command aireplay-ng -9 -e Wireless Lab -a <mac> mon0 on a terminal.

Go back to Wireshark and you should see a lot of packets on the screen now. Some of these packets have been sent by aireplay-ng, which we launched, and others are from the access point Wireless Lab in response to the injected packets.