widely researched for many years. Mobile Ad-hoc Networks are a collection of two or more devices equipped with wireless communications and networking capability. These devices can communication with other nodes that immediately within their radio range or one that is outside their radio range. For the later, the nodes should deploy an intermediate node to be the router to route the packet from the source toward the destination. The Wireless Ad-hoc Networks do not have gateway, every node can act as the gateway. Although since 1990s’, lots of research has been done on this particular field, it has often been questioned as to whether the architecture of Mobile Ad-hoc Networks is a fundamental flawed architecture. The main reason for the argument is that Mobile Ad-hoc Networks are almost never used in practice, almost every wireless network nodes communicate to base-station and access points instead of co-operating to forward packets hop-by-hop. We take the position that Mobile Ad-hoc Networks (MANET) are a fundamentally flawed architecture. As argument, we try to clarify the definition, architecture and the characters of MANET, as well as the main challenges of constructing the MANET. Although many works have been done to solve the problem, we will show in this paper that it is very difficult to solve these limitations which made the Mobile Ad-hoc Networks a flawed architecture. After giving many evidences and analysis, we could see that the key technologies of Wireless Ad-hoc Networks were not implemented as well as we expect. That is to say, many problems are inherently unsolvable. Thus, we could explain why we take the position that Mobile Ad-hoc Networks are flawed architecture.

Abstract — In this paper we compared single path and multipath routing protocols over mobile ad hoc wireless networks using ns-2 simulator. Simulation results are presented by varying number of source, pause time and node mobility.

Abstract — Ad hoc networks are a new wireless networking paradigm for mobile nodes. It enabling devices to create and join networks on-the-fly anywhere, anytime. The military, emergency rescue, disaster relief operations are the main applications of ad hoc networks. Unlike traditional wireless networks, ad hoc networks do not rely on any fixed infrastructure. Instead, hosts rely on each other to keep the network connected. In this paper we compared single path and multipath routing protocols over mobile ad hoc wireless networks using ns-2 simulator. Simulation results are presented by varying number of source, pause time and node mobility.

Secure communication, an important aspect of any networking environment, is an especiallysignicant challenge in ad hoc networks. The MANET paradism seeks to enable communication across networks whose topology and membership can change frequently. Its distinctive feature is that network nodes need to collaborate with their peers in supporting the network functionality. In such an environment, malicious or selfish nodes can disrupt or even deny the communications of potentially any node within the ad hoc networking domain. This is so, exactly because every node in the network is not only entitled, but is in fact required, to assist in the network establishment, the network maintenance, and the network operation. Ad-Hoc Networks consist of peer-topeer communicating nodes that are highly mobile. As such, an ad- hoc network lacks infrastructure and topology of the network