Wireless mesh Architecture

Wireless mesh architecture is a first step towards providing high-bandwidth network over a specific coverage area. Wireless mesh architectures infrastructure is, in effect, a router network minus the cabling between nodes. It's built of peer radio devices that don't have to be cabled to a wired port like traditional WLAN access points (AP) do. Mesh architecture sustains signal strength by breaking long distances into a series of shorter hops. Intermediate nodes not only boost the signal, but cooperatively make forwarding decisions based on their knowledge of the network, i.e. perform routing. Such an architecture may with careful design provide high bandwidth, spectral efficiency, and economic advantage over the coverage area.

Example of three types of wireless mesh network:
Infrastructure wireless mesh networks: Mesh routers form an infrastructure for clients.
Client wireless mesh networks: Client nodes constitute the actual network to perform routing and configuration functionalities.
Hybrid wireless mesh networks: Mesh clients can perform mesh functions with other mesh clients as well as accessing the network.

Wireless mesh networks have a relatively stable topology except for the occasional failure of nodes or addition of new nodes. The traffic, being aggregated from a large number of end users, changes infrequently. Practically all the traffic in an infrastructure mesh network is either forwarded to or from a gateway, while in ad hoc networks or client mesh networks the traffic flows between arbitrary pairs of nodes.

http://en.wikipedia.org/wiki/Wireless_mesh_network#Architecture