Security, Wifi, Wep.
you wanted to show how not to design a protocol, then WEP was certainly in the Top 10, and was integrated into IEEE 802.11b. In the days of IEEE 802.11n which gives rates of 540 Mbps, the transmission rate of 11Mbps for 11b just seems so slow. But it was WEP which caused most of the problem. WEP