Mesh topology

A mesh network is a network topology in which each node (called a mesh node) relays data for the network. All nodes cooperate in the distribution of data in the network.
A mesh network can be designed using a flooding technique or a routing technique. When using a routing technique, the message is propagated along a path, by hopping from node to node until the destination is reached. To ensure all its paths' availability, a routing network must allow for continuous connections and reconfiguration around broken or blocked paths, using self-healing algorithms. A mesh network whose nodes are all connected to each other is a fully connected network. Mesh networks can be seen as one type of ad hoc network. Mobile ad hoc networks (MANET) and mesh networks are therefore closely related, but MANET also have to deal with the problems introduced by the mobility of the nodes.
The self-healing capability enables a routing based network to operate when one node breaks down or a connection goes bad. As a result, the network is typically quite reliable, as there is often more than one path between a source and a destination in the network. Although mostly used in wireless situations, this concept is also applicable to wired networks and software interaction.

In communication networks, a node (Latin nodus, ‘knot’) is either a connection point, a redistribution point or a communication endpoint (some terminal equipment). The definition of a node depends on the network and protocol layer referred to. A physical network node is an active electronic device that is attached to a network, and is capable of sending, receiving, or forwarding information over a communications channel.[1] A passive distribution point such as a distribution frame or patch panel is consequently not a node.
Advantages
Point-to-point line configuration makes identification and isolation of faults easy.
Messages travel through a dedicated line, directly to the intended recipient; privacy and security are thus enhanced.
Should a fault occur in a given link, only those communications between that specific pair of devices sharing the link will be affected.

Disadvantages
The more extensive the network, in terms of scope or of physical area, the greater the investment necessary to build it will be, due, among other considerations, to the amount of cabling and the number of hardware ports it will require. For this reason, such networks are uncommon.
Because every device must be connected to every other device, installation and reconnection are difficult.
The huge bulk of the wiring can often be greater than the available space in the ceiling or under floors can accommodate.[dubious – discuss]
Wireless mesh networks
Wireless mesh networks were originally developed for military applications. Mesh networks are typically wireless. Over the past decade, the size, cost, and power requirements of radios has declined, enabling multiple radios to be contained within a single device, i.e., mesh node, thus allowing for greater modularity; each can handle multiple frequency bands and support a variety of functions as needed—such as client access, backhaul service, and scanning (required for high-speed handoff in mobile applications)—even customized sets of them.
Work in this field has been aided by the use of game theory methods to analyze strategies for the allocation of resources and routing of packets.

Mesh topology
A network setup where each computer and network device is interconnected with one another, allowing for most transmissions to be distributed, even if one of the connections go down. This topology is not commonly used for most computer networks as it is difficult and expensive to have redundant connection to every computer. However, this topology is commonly used for wireless networks. Below is a visual example of a simple computer setup on a network using a mesh topology.

The illustration shows a full mesh network with five nodes. Each node is shown as a sphere, and connections are shown as straight lines. The connections can be wired or wireless.

A mesh network is reliable and offers redundancy. If one node can no longer operate, all the rest can still communicate with each other, directly or through one or more intermediate nodes. Mesh networks work well when the nodes are located at scattered points that do not lie near a common line.

The chief drawback of the mesh topology is expense, because of the large number of cables and connections required. In some scenarios, a ring network or star network may prove more cost effective than a mesh network. If all the nodes lie near a common line, the bus network topology is often the best alternative in terms of cost.