Controlling TCP Fairness in WLAN access networks using a Rate Limiter approach

摘要

This paper deals with application level QoS and fairness issues in IEEE 802.11 Wireless LANs. The current implementations of 802.11 use the DCF, which gives the same medium access priority to all stations. However, fairness at the MAC level does not necessarily translate in fairness at the application level, particularly in presence of TCP-based applications, operating in an infrastructured network topology. Unfairness at application level may result in users perceiving unsatisfactory levels of QoS. This paper addresses fairness related phenomena, as experienced by TCP-based applications, and proposes a solution able to offer fair performances to final users with minimal additional complexity. The proposed solution, based on rate control mechanisms, avoid TCP critical unfairness. Our solution operate at the IP level and is fully compatible with existing devices. Moreover, it seems appealing for its easiness of implementation. Also, we analyzed fairness phenomena and evaluated the performance of our solution by means of simulations.