29-03-2011, 04:31 PM
Mobile ad hoc network (MANET):
Communication has become very important for people to exchange information anytime from and to anywhere. Mobile Ad hoc Networks, called MANETs, are becoming useful as the existing wireless infrastructure is expensive and inconvenient to use. They are going to become integral part of next generation mobile services. A MANET is a collection of wireless nodes that can dynamically form a network to exchange information without using any pre-existing fixed network infrastructure. The abilities of ad hoc networks are recognized and it is used for security-sensitive operations, although there is a trend to adopt ad hoc networks for commercial uses due to their unique properties.
During the last decade, advances in both hardware and software techniques have resulted in mobile hosts and wireless networking common and miscellaneous. Generally there are two distinct approaches for enabling wireless mobile units to communicate with each other: Infrastructured and Infrastructureless. Traditionally wireless mobile networks are based on the cellular concept and relied on good infrastructure support, in which mobile devices communicate with access points like base stations connected to the fixed network infrastructure. Typical examples of this kind of wireless networks are GSM, UMTS, WLL, WLAN, etc.
Infrastructureless approach is commonly known as a mobile ad hoc network (MANET). A MANET is a collection of wireless nodes that can dynamically form a network to exchange information without using any pre-existing fixed network infrastructure.
MANET v/s WLAN
MANETs are dynamically created and maintained by the individual nodes comprising the network. They do not require a pre-existing architecture for communication purposes and do not rely on any type of wired infrastructure; in an ad hoc network all communication occurs through a wireless median.
MANET comprises a special subset of wireless networks since they do not require the existence of a centralized message-passing device. Simple wireless networks require the existence of access points or static base stations, which are responsible for routing messages to and from mobile nodes within the specified transmission area.
Ad hoc networks, on the other hand, do not require the existence of any device other than two or more MNs willing to cooperatively form a network. Instead of relying on a wired base station to coordinate the flow of messages to each mobile node, the individual mobile nodes form their own network and forward packets to and from each other. This adaptive behaviour allows a network to be quickly formed even under the most adverse conditions.
