Analysis of TCP Performance over

Mobile ad hoc networks have gained a lot of attention lately as a means of providing continuous network connectivity to mobile computing devices regardless of physical location. Recently, a large amount of research has focused on the routing protocols needed in such an environment. In this two-part report, we investigate the eeects that link breakage due to mobility has on TCP performance. Through simulation, we show that TCP throughput drops signiicantly when nodes move because of TCP's inability to recognize the diierence between link failure and congestion. We also analyze speciic examples, such as a situation where throughput is zero for a particular connection. We introduce a new metric, expected throughput, for the comparison of throughput in multi-hop networks, and then use this metric to show how the use of explicit link failure notiication (ELFN) techniques can signiicantly improve TCP performance. In this paper (Part I of the report), we present the problem and an analysis of our simulation results. In Part II of this report, we present the simulation and results in detail.