Dynamic Fair Queuing (DFQ): A Novel Fair Scheduler Improving Wireless TCP over Hybrid LAN with Wired and Wireless Links

Local area network (LAN) will be a hybrid network that includes wired and wireless links together. Nonetheless, the wired hosts always take the most bandwidth and bring about the bandwidth allocation unfairness. This problem is caused by the flow control mechanism that is dominated by the round-trip time (RTT). Among the connections on a share link, the ones with shorter RTT tend to acquire bandwidth easier and exhaust the link bandwidth eventually. The RTT of wireless transmission is much longer than wired transmission. Therefore, the protocol that implements flow control mechanism such as TCP suffers a severe low performance problem on wireless links. This paper proposed a new scheme called DFQ that works on gateway. It prevents the wired hosts from grabbing the bandwidth of share link too much and averts the unfairness or starvation of wireless connections. The DFQ has been implemented and test on Linux OS. The experiment result shows that DFQ is practicable and makes wireless network to work with wired network seamlessly.