Mesh networking

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Image showing mesh network layout
Image showing mesh network layout
Animation showing self healing wireless mesh (enlarge)
Animation showing self healing wireless mesh (enlarge)

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.

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. 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.

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[edit] 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 a single-radio mesh network being used within a community as opposed to multi-radio long range mesh networks like Belair,[2] Strix Systems, or MeshDynamics,[3] that provide multifunctional infrastructure.

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 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.[5] 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.[6]

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.[7]

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.[8] 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.

Many mesh networks operate across multiple radio bands. For example Firetide and Wave Relay mesh networks have the option to communicate node to node on 5.2 GHz or 5.8 GHz, but communicate node to client on 2.4 GHz (802.11). This is accomplished using SDR (Software Defined Radio.)

The SolarMESH project examined the potential of powering 802.11-based mesh networks using solar power and rechargeable batteries.[9] Legacy 802.11 access points were found to be inadequate due to the requirement that are continuously powered.[10] The IEEE 802.11s standardization efforts are considering power save options, but solar-powered applications might involve single radio nodes where relay-link power saving will be inapplicable.


[edit] See also

[edit] Mesh network applications

[edit] Mesh network devices

[edit] Technical challenges

[edit] External links

[edit] References

  1. ^ Meraki Mesh. meraki.com. Retrieved on 2008-02-23.
  2. ^ Muni WiFi Mesh Networks. belairnetworks.com. Retrieved on 2008-02-23.
  3. ^ Meshdynamics : Highest performance Voice, Video and Data Outdoors. meshdynamics.com. Retrieved on 2008-02-23.
  4. ^ Robert Lee Lounsbury, Jr.. "OPTIMUM ANTENNA CONFIGURATION FOR MAXIMIZING ACCESS POINT RANGE OF AN IEEE 802.11 WIRELESS MESH NETWORK IN SUPPORT OF MULTIMISSION OPERATIONS RELATIVE TO HASTILY FORMED SCALABLE DEPLOYMENTS". Retrieved on 2008-02-23.
  5. ^ XO-1 Mesh Network Details. laptop.org. Retrieved on 2008-02-23.
  6. ^ SONbuddy : Network without Network. sonbuddy.com. Retrieved on 2008-02-23.
  7. ^ Cambridge Strawberry Fair. cambridgeshiretouristguide.com. Retrieved on 2008-02-23.
  8. ^ SMesh. smesh.org. Retrieved on 2008-02-23.
  9. ^ SolarMesh. mcmaster.ca. Retrieved on 2008-04-15.
  10. ^ Terence D. Todd, Amir A. Sayegh, Mohammed N. Smadi, and Dongmei Zhao. The Need for Access Point Power Saving in Solar Powered WLAN Mesh Networks. In IEEE Network, May/June 2008.