A mesh network is a type of wireless networking that uses redundant and distributed nodes to provide greater reliability and range for any given wireless network. A number of smaller nodes, called repeaters, connect to large nodes or wireless routers to provide coverage over a larger area than would be possible with a wireless router alone. Mesh network software is built around the idea of self-healing networks, capable of routing signals efficiently through complex series of nodes and continuing to work effectively even when some nodes are down.
The idea of providing wireless Internet to large numbers of people became very appealing after the advent of cheap wireless cards in the mid-90s, which thereafter allowed the Internet to become a mobile, often inexpensive phenomenon. Since then, multiple cities, including large metropolitan areas such as Pittsburgh, have adopted the goal of providing free wireless network access everywhere. This would make the Internet not only mobile and costless, but nearly ubiquitous. In 2005, the initiative was brought to the federal level in a report by the IEEE-USA's Committee on Communications and Information Policy, which declared that the U.S. must move as fast as possible to deploy ubiquitous, gigabit-plus wireless networks or suffer the long-term economic consequences. The mesh network is an ideal solution.
When the idea of providing wireless networking to large areas, especially entire metropolitan regions, is discussed, two directions for growth are commonly considered -- increasing the range of any given wireless node, or increasing the total number of wireless nodes for better coverage. While new protocols and technology standards will increase the range of wireless nodes by a factor of two or three, larger extensions of wireless range seem unlikely, barring some unorthodox approach such as the mass launch of airships serving as wireless broadcasters. The only other alternative is to increase the number of wireless nodes in operation, miniaturize them, minimize their cost and develop better software to route data among complex, multi-noded networks -- pursuits which all fall under the banner of mesh network technology. Recently, several dozen companies, including Google, have offered to equip San Francisco with a wireless mesh network for free.
The mesh network has attracted a lot of attention since wireless technology first started becoming affordable, already generating 70 competing protocols for routing data across mesh networks. Companies such as Insteon provide customers with mesh networks for use in the home or at the office, offering to integrate wireless technology into everyday appliances such as a microwave or gas meter. As the mesh network becomes sufficiently small and cheap, it will become integrated with a variety of devices in our everyday lives, further blending the line between the virtual and the real.