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* [http://http://www.meshdynamics.com/documents/jwarn-aoa-final-draft-040606.pdf Battelle Report] Evaluation of popular mesh network providers, specific to military applications.
* [http://www.pdos.lcs.mit.edu/roofnet/ MIT Roofnet] A research project at MIT that forms the basis of roofnet / [[Meraki]] mesh networks
* [http://www.pdos.lcs.mit.edu/roofnet/ MIT Roofnet] A research project at MIT that forms the basis of roofnet / [[Meraki]] mesh networks
* [http://www.wing-project.org WING Project] Wireless Mesh Network distribution based on the roofnet source code
* [http://www.wing-project.org WING Project] Wireless Mesh Network distribution based on the roofnet source code

Revision as of 03:01, 14 January 2013

For other meanings of the word mesh, see Mesh (disambiguation).
Illustration of a mesh network

Mesh networking (topology) is a type of networking where each node must not only capture and disseminate its own data, but also serve as a relay for other nodes, that is, it must collaborate to propagate the 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.

Advantages

  • Point to point line configuration makes identification and isolation of faults easy.
  • Messages travel through a dedicated line meaning that only the intended recipient receives the message: privacy and security is thus ensured,
  • In the case of a fault in one link, only the communication between the two devices sharing the link is affected.
  • The use of dedicated links ensures that each connection carries its own data load thus ridding of traffic problems that would have been encountered if a connection/link was shared.

Disadvantages

  • If the network covers a great area, huge investments may be required due to the amount of cabling and ports required for input and output devices. It is a rare choice of a network connection due to the costs involved.

Wireless mesh networks

Wireless mesh networks were originally developed for military applications and are typical of mesh architectures. Over the past decade the size, cost, and power requirements of radios has declined, enabling more radios to be included within each device acting as a mesh node. The additional radios within each node enable it to support multiple functions such as client access, backhaul service, and scanning (required for high speed handover in mobile applications). Additionally, the reduction in radio size, cost, and power has enabled the mesh nodes to become more modular—one node or device now can contain multiple radio cards or modules, allowing the nodes to be customized to handle a unique set of functions and frequency bands.

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.[1] [2] [3]

Examples

Zigbee digital radios are incorporated into some consumer appliances, including battery-powered appliances. Zigbee radios spontaneously organize a mesh network, using AODV routing. The transmission and reception are synchronized. This can save power because the radios can be off most of the time.

Building a Rural Wireless Mesh Network: A DIY Guide (PDF)

In early 2007, the US-based firm Meraki launched a mini wireless mesh router.[4] 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 metres. 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[5] or MeshDynamics[6] that provide multifunctional infrastructure.

The Naval Postgraduate School, Monterey CA, demonstrated a wireless mesh network for border security.[7] 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"(One Laptop per Child) which is intended for disadvantaged schools in developing nations and uses mesh networking (based on the IEEE 802.11s standard) to create a robust and inexpensive infrastructure.[8] 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.[9]

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.[10]

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. Additionally, the Wireless Networking Group [11] in the University of Illinois at Urbana-Champaign are developing a multichannel, multi-radio wireless mesh testbed, called Net-X as a proof of concept implementation of some of the multichannel protocols being developed in that group. The implementations are based on an architecture that allows some of the radios to switch channels to maintain network connectivity, and includes protocols for channel allocation and routing.[12]

SMesh is an 802.11 multi-hop wireless mesh network developed by the Distributed System and Networks Lab at Johns Hopkins University.[13] 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.[14] Legacy 802.11 access points were found to be inadequate due to the requirement that are continuously powered.[15] 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.

The WING project [16] (sponsored by the Italian Ministry of University and Research and led by CREATE-NET and Technion) developed a set of novel algorithms and protocols for enabling wireless mesh networks as the standard access architecture for next generation Internet. Particular focus has been given to interference and traffic aware channel assignment, multi-radio/multi-interface support, and opportunistic scheduling and traffic aggregation in highly volatile environments.

WiBACK Wireless Backhaul Technology has been developed by the Fraunhofer Institute for Open Communication Systems (FOKUS) in Berlin. Powered by solar cells and designed to support all existing wireless technologies, networks are due to be rolled out to several countries in sub-Saharan Africa in summer 2012.[17]

Recent standards for wired communications have also incorporated concepts from Mesh Networking. An examples is ITU-T G.hn, a standard that specifies a high-speed (up to 1 Gigabit/s) local area network using existing home wiring (power lines, phone lines and coaxial cables). In noisy environments such as power lines (where signals can be heavily attenuated and corrupted by noise) it's common that mutual visibility between devices in a network is not complete. In those situations, one of the nodes has to act as a relay and forward messages between those nodes that cannot communicate directly, effectively creating a mesh network. In G.hn, relaying is performed at the Data Link Layer.

See also

Wikimedia Commons has media related to Mesh network.

Mesh network applications

Mesh network devices

Technical challenges

References

  1. ^ J. Huang, D. P. Palomar, N. Mandayam, J. Walrand, S. B. Wicker, and T. Basar, "Game Theory in Communication Systems", IEEE Journal on Selected Areas in Communications, Vol. 26 No. 7, Sep. 2008. Link
  2. ^ Hubaux, J.-P.; Ganeriwal, S.; Aad, I. (2005). "On selfish behavior in CSMA/CA networks".
  3. ^ Shi, Zhefu; Beard, Cory; Mitchell, Ken (2011). "Competition, cooperation, and optimization in Multi-Hop CSMA networks".
  4. ^ "Meraki Mesh". meraki.com. Archived from the original on 2008-02-19. Retrieved 2008-02-23.
  5. ^ "Muni WiFi Mesh Networks". belairnetworks.com. Retrieved 2008-02-23.
  6. ^ "Meshdynamics : Highest performance Voice, Video and Data Outdoors". meshdynamics.com. Retrieved 2008-02-23.
  7. ^ 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" (PDF). Retrieved 2008-02-23. {{cite journal}}: Cite journal requires |journal= (help) [dead link]
  8. ^ "XO-1 Mesh Network Details". laptop.org. Retrieved 2008-02-23.
  9. ^ "SONbuddy : Network without Network". sonbuddy.com. Retrieved 2008-02-23.
  10. ^ "Cambridge Strawberry Fair". cambridgeshiretouristguide.com. Retrieved 2008-02-23.
  11. ^ "Wireless Networking Group".
  12. ^ "Wireless Networking Group" (PDF).
  13. ^ "SMesh". smesh.org. Retrieved 2008-02-23.
  14. ^ "SolarMesh". mcmaster.ca. Retrieved 2008-04-15.
  15. ^ 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.
  16. ^ http://www.wing-project.org WING
  17. ^ "Broadband internet for everyone". eurekalert.org. Retrieved 2012-02-16.
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