M obile Ad Hoc Networks (M ANETs) are networks of mobile computing nodes (e.g. portable computers, PDAs etc.) equipped with wireless interfaces and communicating with each other without relying on any infrastructure. In these networks each mobile node may act as a client, a server and a router. M ANETs have emerged to fulfill the need for communication of mobile users in locations where deploying a network infrastructure is impossible, or too expensive, or simply is not available at that time. Characteristic scenarios for M ANETs are disaster relief operations, battlefields and locations where infrastructure-based WLAN coverage (also called hotspots) is not provided and wireless WANs (e.g. GPRS/UMTS) are too expensive to use or too slow. M ost of the research on M ANETs has focused on issues dealing with the connectivity between mobile nodes in order to cope with the dynamism of such networks and the arising p roblems thereof. This dynamism is due to the mobility of nodes, the wireless channel’s adverse and fast changing conditions and the energy limitations of mobile nodes, all of which lead to frequent disconnections and/or node failures. These research efforts have led to the creation of a sound technical basis for dealing with the aforementioned problems regarding node connectivity in M ANETs (mainly through Zone Routing Protocol). However, solving the problems of connectivity alone is not sufficient for the adoption of M ANETs. Since their basic role is to allow mobile users to exchange data and use each other’s services, there is also a need for architectures, mechanisms and protocols to tackle route failures and minimize the control overhead.