Practical node policing in 802.11WLANs

As open-source WiFi device drivers are increasingly available, wireless equipment can be configured to disobey the 802.11 specification, with the goal of achieving performance gains, to the detriment of fair users.We demonstrate a practical implementation of a node policing scheme that combats such selfish behaviour, using commercial off-the-shelf hardware and a modified firmware. With a small testbed, we show that access points running our scheme can detect misbehaving stations, inflict punishment upon them and effectively restore fairness in the network.