MANET ( Mobile Ad-hoc Network) is the IETF working group that is concerned with the standardization of ad-hoc protocols running over IP. However, to benefit fully, a number of pitfalls to be overcome, such as quality of service and security, because of the mobility of nodes. The benefits of ad-hoc networks are their simple extensions, physical coverage and cost. Mobile which acts as gateways – usually all mobile – implement a router in the circuits, so that the problems arising essentially return to the Internet routing problems, the mobility is managed by IP Mobile. The solution developed for ad-hoc networks takes to the foundation IP environment. However, the fact that all portable play the role of BSS and are themselves mobile, new properties should be made to the management of user addresses and control routing. The access techniques are the same type as in mobile networks. Obviously, in this case, the overall throughput is optimized, since there may be a high frequency reuse. In the second case, if a device fails or is turned off, the network can be cut into two separate subnets, without communication with each other. Network throughput is minimal, the frequencies that can not be reused. The advantage of the first solution is the transmission security, since you can go directly from the sender to the receiver, without depending on an intermediate device. In the second solution, instead, the radio range is as short as possible: in a communication between two nodes, it usually go through several intermediate machines. The first is that of an ad-hoc network in which all nodes can communicate with all the other involving long-range transmitters. The main problem caused by this network comes from the definition of the network topology: how to identify the neighboring nodes and how to get from one node to another node? Two extremes can be compared. Two moving too far away from each other to directly communicate can find an intermediate wheel able to act as relays. In other words, the mobile can act as a gateway for allowing a mobile communication to another. They aim to achieve a communication environment that unfolds without any other infrastructure that mobile themselves. Contrary to appearances, ad-hoc networks date back several decades.
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