Greedy Behavior in Wireless Network Hotspots

Wireless LANs were originally meant to be deployed in protected locations such as corporate offices; But, over the last few years, IEEE 802.11 has also become the dominating solution for hotspots, which provide public wireless access to the Internet. Furthermore, the increased level of sophistication in the design of protocol components, together with the requirement for flexible and readily reconfigurable protocols has led to the extreme where wireless network adapters and devices have become easily programmable. As a result, it is feasible for a network peer to tamper with software and firmware, modify its wireless interface and network parameters and ultimately abuse the protocol, Wireless Medium Access Control (MAC) protocols such as IEEE 802.11 use distributed contention resolution mechanisms for sharing the wireless channel where a greedy user can substantially increase his share of bandwidth, at the expense of the other users by slightly modifying the driver of his network adapter. We explain how easily this can be performed,in particular with the new generation of adapters. We then present a new enhanced system to detection greedy behavior in the MAC layer IEEE 802.11.