International audienceMost existing TCP variants cannot distinguish between different packet loss causes within MANETs. TCP was, mainly, developed to deal with network congestion errors. While within MANETs, there are packet loss causes other than congestion. Studying the behaviour of TCP in front of such losses, we notice that TCP doesn't have always the optimum behaviour as it reacts, in most cases, without considering the loss cause. This misbehaviour might cause network performance degradation and resources' waste. To overcome this problem, many LDAs have been designed. However, these LDAs were optimized for data networks where wireless link is only the last hop, meaning that they might be inadequate for MANETs. Also, the proposed LDAs deal only with losses due to wireless channel and/or congestion-induced errors. We show, in this paper, the importance of dealing with a third loss cause that is common in MANETs, which is link failure. We propose a new TCP variant that is called TCP-WELCOME. TCP-WELCOME can: (i) identify the loss cause by coupling loss and delay information, and (ii) trigger the appropriate packet loss recovery according to the identified loss cause. The performance evaluation, through both simulations and experimental tests, shows that TCP-WELCOME optimizes both energy consumption and achievable throughput. TCP-WELCOME does not change the standard and can operate with existing TCP variants

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The authors present, in this chapter, the work done in order to improve TCP performance and to cope with new data transmission network technologies and topologies (such as Wi-Fi, WiMAX, cellular, wireless, mobile, ad-hoc, Mesh, and Vehicular networks). They also discuss the remaining research challenges that should be studied and evaluated within such wireless networks.