Ad hoc network.pptVIP

Mobile Ad-hoc network(MANET) Origin Mobile Ad-hoc network is not a new technology, formerly known as PRNET which is researched by DARPA (Defense Advanced Research Projects Agency) of United States. Definition A mobile ad hoc network (MANET) is a self-configuring infrastructureless network of mobile devices connected by wireless. Features Distributed operation It means MANET is not like the cellular network or Internet ,nodes in MANET do not depend on a sink node or operations center .All the nodes have equal status, they can deal with things by themselves. Limited bandwidth and link change frequently Wireless environment is very complicated and unpredictable. Its bandwidth capacity is far less than wired network. Considering the multiple access、fading and noise factor, the link between two nodes become more vulnerable. Multi-hop Due to the limited transmission range of nodes , the self organizing network is built based on multi hop. Each node must forward traffic unrelated to its own use for other nodes in the network. Therefore each mobile node not only as a host but also as a router. Equipment constraints Device used in Mobile Ad-hoc wireless networks is usually small, which may cause highly constraint of energy resources. Also the compute capacity is restricted. Technical requirements To realize ad-hoc protocols , that controls how nodes decide communicate in a mobile ad hoc network. Similarly to the computer network, it can be divided into five parts: MAC( Physical layer、data link layer)、network layer、transport layer、application layer. Routing protocols In ad hoc networks, nodes are not familiar with the topology of their networks. Instead, they have to discover it. typically, a new node announces its presence and listens for announcements broadcast by its neighbors. Each node learns about others nearby and how to reach them, and may announce that it can reach them. This can establish a preliminary routing. Routing protocols in MANET can be usually d