Mesh networking is a way to route data, voice and instructions between nodes. It allows for continuous connections and reconfiguration around broken or blocked paths by “hopping” from node to node until the destination is reached. A mesh network whose nodes are all connected to each other is a fully connected network. Mesh networks differ from other networks in that the component parts can all connect to each other via multiple hops, and they generally are not mobile. Mesh networks can be seen as one type of ad hoc network. Mobile ad hoc networks (MANETs), and mesh networks are therefore closely related, but MANETs also have to deal with the problems introduced by the mobility of the nodes.

Mesh networks are self-healing: the network can still operate even when a node breaks down or a connection goes bad. As a result, a very reliable network is formed. This concept is applicable to wireless networks, wired networks, and software interaction. The animation below illustrates how wireless mesh networks can self form and self heal. For more animations see History of Wireless Mesh Networking

Wireless mesh networks is the most topical application of mesh architectures. Wireless mesh was originally developed for military applications but have undergone significant evolution in the past decade. As the cost of radios plummeted, single radio products evolved to support more radios per mesh node with the additional radios providing specific functions- such as client access, backhaul service or scanning radios for high speed handover in mobility applications. The mesh node design also became more modular - one box could support multiple radio cards - each operating at a different frequency.

Examples

In early 2007, the US-based firm Meraki launched a mini wireless mesh router. This is an example of a wireless mesh network (on a claimed speed of up to 50 megabits per second). The 802.11 radio within the Meraki Mini has been optimized for long-distance communication, providing coverage over 250 meters. This is an example of a single-radio mesh network being used within a community as opposed to multi-radio long range mesh networks like Belair, Strix Systems, or MeshDynamics, that provide multifunctional infrastructure.

The Naval Postgraduate School, Monterey CA, demonstrated a wireless mesh network for border security. In a pilot system, aerial cameras kept aloft by balloons relayed real time high resolution video to ground personnel via a mesh network.

An MIT Media Lab project has developed the XO-1 laptop or "OLPC" which is intended for under-privileged schools in developing nations and uses mesh networking (based on the IEEE 802.11s standard) to create a robust and inexpensive infrastructure. The instantaneous connections made by the laptops are claimed by the project to reduce the need for an external infrastructure such as the internet to reach all areas, because a connected node could share the connection with nodes nearby. A similar concept has also been implemented by Greenpacket with its application called SONbuddy.