Explained: Ad hoc networks
In recent years, many network scientists have turned their attention away from centralized networks — such as the Internet and the cell-phone network — and toward ad hoc networks, wireless networks formed on the fly by, say, emergency responders fanning through a burning building, tiny sensors scattered on the slopes of a volcano to monitor its activity, or autonomous robots exploring a forbidding environment. “The problems are very tantalizing, they’re exciting to work on and they have an interesting mathematical structure,” says Nancy Lynch, NEC Professor of Software Science and Engineering. “All of traditional distributed-computing theory deals with wired-network algorithms, so those communication protocols have been studied for many years.”In the Internet, the responsibility for directing data traffic lies with special-purpose devices called routers. Internet service providers monitor the flow of traffic across their networks and, if they spot congestion, revise the routers’ instructions accordingly. With the cell network, two...