The TCP protocol exhibits poor performance in multi-hop Mobile Ad Hoc Networks (MANETs). The ultimate reason for this is that MANETs behave in a significantly different way from traditional wired networks (like the Internet) for which the TCP protocol was originally designed. In particular, route failures and route changes due to node mobility may be frequent events in MANETs. Furthermore, congestion phenomena in MANETs are essentially different from traditional wired networks. In this paper we propose a novel transport protocol for MANETs. Unlike other proposals, our protocol is not a modification of the TCP but is specifically tailored to the characteristics of the MANET environment. It is able to manage efficiently route changes and route failures. Furthermore, it includes a completely re-designed congestion control mechanism. Finally, it is designed in such a way to reduce as much as possible the number of useless retransmissions. This is extremely important since retransmissi...