Performance Study of TCP Veno over WLAN and RED Router

Abstract

This paper examines the impact of RED on two versions of TCP - traditional TCP Reno and a newly proposed variant, TCP Veno - over 802.11b WLAN. TCP Reno was originally designed for wired networks where packet losses are primarily due to network congestion. This assumption is not always true in wireless networks, in which packet losses can be due to transmission errors on the noisy wireless link. TCP Veno refines the algorithms in Reno by distinguishing between noncongestive and congestive states, and avoids the unnecessary reduction of TCP congestion window when packet losses are not due to congestion. Our results show that TCP Veno can achieve up to 30% more throughput than TCP Reno when link quality is poor. Our results also show that TCP Veno is compatible with RED. In addition, although RED does not help to further improve the throughput in Veno, it can improve fairness among co-existing TCP flows.