ADHOC BASIC CONCEPTS
A wireless ad hoc network (WANET) is a decentralized type of
wireless network. The network is ad hoc because it does not rely on a pre existing
infrastructure, such as routers in wired networks or access points in managed
(infrastructure) wireless networks. Instead, each node participates in routing
by forwarding data for other nodes, so the determination of which nodes forward
data is made dynamically on the basis of network connectivity.
In addition to the classic routing, ad hoc networks can use
flooding for forwarding data. Wireless mobile ad hoc networks are
self-configuring, dynamic networks in which nodes are free to move. Wireless networks
lack the complexities of infrastructure setup and administration, enabling
devices to create and join networks "on the fly" - anywhere, anytime.
A wireless ad-hoc network, also known as IBSS - Independent
Basic Service Set, is a computer network in which the communication links are
wireless. The network is ad-hoc because each node is willing to forward data
for other nodes, and so the determination of which nodes forward data is made
dynamically based on the network connectivity. This is in contrast to older
network technologies in which some designated nodes, usually with custom
hardware and variously known as routers, switches, hubs, and firewalls, perform
the task of forwarding the data.
Minimal configuration and quick deployment make ad hoc networks
suitable for emergency situations like natural or human-induced disasters,
military conflicts. The earliest wireless ad-hoc networks were called
"packet radio" networks, and were sponsored by Defense Advanced
Research Projects Agency (DARPA) in the early 1970s. Bolt, Beranek and Newman
Technologies (BBN) and SRI International designed, built, and experimented with
these earliest systems.
Experimenters included Jerry Burchfield, Robert Kahn, and Ray
Tomlinson of later TEN-EXtended (TENEX), Internet and email fame. Similar
experiments took place in the Ham radio community. It is interesting to note
that these early packet radio systems predated the Internet, and indeed were
part of the motivation of the original Internet Protocol suite. Later DARPA experiments
included the Survivable Radio Network (SURAN) project, which took place in the
Another third wave of academic activity started in the mid-1990s
with the advent of inexpensive 802.11 radio cards for personal computers.
Current wireless ad-hoc networks are designed primarily for military utility.