topology mesh networking

Mesh networking
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Image showing mesh network layout
Animation showing self healing wireless mesh (enlarge)
Three generations of wireless mesh topologies

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 networking (MANet), and mesh networking are therefore closely related, but mobile ad hoc networks 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.

An animation of a wireless mesh network is shown on the right. Watch what happens when the mesh nodes power up (green LED on box turns on). The nodes hear each other's broadcast and a network is automatically formed. Also watch what happens when a node fails. The nodes re-discover an alternate routing path. Network connectivity is thus preserved automatically.

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.

Wireless mesh networking has seen three distinct radio configurations of mesh technology, each incorporating iterative improvements allowing for greater reliability and versatility. 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. As a result, a whole new set of applications are being enabled by third generation mesh networking technology. These include real time video surveillance, border security or voice communication inside underground mines.Contents [hide]
1 Examples
2 See also
2.1 Mesh network applications
2.2 Mesh network devices
3 Technical challenges
4 External links
5 References


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Examples

In early 2007, the US-based firm Meraki launched a mini wireless mesh router.[1] 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 mesh network being used within a community as opposed to multi-radio long range mesh networks like Belair.[2] or MeshDynamics [3]

The Naval Postgraduate School, Monterey CA, demonstrated a wireless mesh network for border security.[4] In a pilot system, aerial cameras kept aloft by balloons relayed real time high resolution video to ground personnel via a mesh network.

A Massachusetts Institute of Technology project is developing the XO-1 laptop or "OLPC" which is intended for under-privileged schools in developing nations and plans to use mesh networking 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 by its application called SONbuddy.[5]

In Cambridge, UK, on the 3rd June 2006, mesh networking was used at the “Strawberry Fair” to run mobile live television, radio and internet services to an estimated 80,000 people.[6]

The Champaign-Urbana Community Wireless Network (CUWiN) project is developing mesh networking software based on open source implementations of the Hazy-Sighted Link State Routing Protocol and Expected Transmission Count metric.

SMesh is an 802.11 multi-hop wireless mesh network developed by the Distributed System and Networks Lab at Johns Hopkins University.[7] A fast handoff scheme allows mobile clients to roam in the network without interruption in connectivity, a feature suitable for real-time applications, such as VoIP.

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See also

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Mesh network applications
Wireless mesh network
Distinct radio node deployments of Wireless Mesh Networking
BioWeb
Wireless ad-hoc network
Wireless community network
Mobile ad-hoc network
Vehicular ad-hoc network
Intelligent Vehicular AdHoc Network refer Google Groups-INADVENC

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Mesh network devices
MeshBox