17 MANET versus WSN JA Garcia-Macias 1 and Javier Gomez 2 1 CICESE, Código Postal 22860, Ensenada, B.C. Mexico 2 Electrical Engineering Department, National University of Mexico, Ciudad Uni versitaria, Coyoacan, C.P. 04510, D. F. Mexico 17.1 Introduction A mobile ad-hoc network (MANET) is a self-configuring network where nodes, connected by wireless links, can move freely and thus the topology of the network changes constantly. A great amount of resources has been devoted to research in the MANET field in the past three decades; many conferences have been held, many projects have been funded, many articles have been written; however very few MANET-type applications have emerged from all this hard work. A great body of knowledge about MANETs has been produced and many researchers in the field are now trying to apply this knowledge to the field of wireless sensor networks (WSN). The reasoning is that both MANETs and WSNs are auto- configurable networks of nodes connected by wireless links, where resources are scarce, and where traditional protocols and networking algorithms are inadequate. However, as we discuss in this chapter, great care should be taken before applying algorithms, protocols, and techniques to WSNs, if they were originally developed for MANETs. Although, both types of networks indeed have many similarities, the differences are also such that WSN can arguably be considered a whole differ- ent research field. 17.2 Similarities Probably the main reason why WSNs immediately resemble an ad hoc network is because both are distributed wireless networks (i.e., there is not a significant net- work infrastructure in place) and the fact that routing between two nodes may in- volve the use of intermediate relay nodes (also known as multihop routing). Be- sides, there is also the fact that both ad hoc and sensor nodes are usually battery- powered and therefore there is a big concern on minimizing power consumption. Both networks use a wireless channel placed in an unlicensed spectrum that is prone to interference by other radio technologies operating in the same frequency.