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Mesh Networks

Architecture

Mesh wireless is a device-as-infrastructure network architecture that operates using common network protocols such as 802.11 b/g/n Wi-Fi on 2.4GHz and 5GHz WiFi frequencies, running on easily accessible hardware components such as routers and smartphones. Using these components, users build a network both by obtaining access to Internet connections and putting up “nodes” (devices able to relay mesh traffic) to extend the reach and strength of wireless coverage. A distributed network infrastructure thus provides multiple paths for communication without any need for centrally-located towers, and allows members of the network to connect directly to each other in an organic and decentralized way, in a fashion that mirrors how communities grow and interact naturally.

Equipment (device) costs can vary based on specifications and quality, but for existing deployments, OTI has identified basic devices in the $40-50 range and higher quality devices in the $75-$80 range. Routers generally use around $.63 of electricity per month, or about the amount used to power a clock radio. Open-source software for wireless mesh devices is developed by OTI and available for free for users.

Benefits of a Wireless Mesh Network

Wireless mesh networking provides a robust and reliable participatory communications medium that supports both local-to-local and local-to-global communication without the need for centralized infrastructure. The benefits of such a decentralized system include:

  • Interoperability with low-cost consumer devices and high-end carrier class devices
  • Support for local applications and services, running the gamut from hyper-local (i.e., neighborhood or block) community organization applications to metro-scale multicast systems
  • Ability to opportunistically make use of unlicensed and licensed wireless spectrum
  • Support for multiple diverse uplinks
  • Support for a a continuum of centralized and decentralized network management
  • Support for multilayer security standards
  • Ease and flexibility of deployment, of precisely the kind needed in both reactive and proactive crisis management, disaster relief, and humanitarian aid efforts.

Hub & Spoke Wireless Networks vs. Mesh Wireless Networks

Most wireless networks, including cellular networks, utilize a “hub and spoke” architecture that is quite similar to the spokes on a bicycle wheel. In the network, users connect with other users via a centrally-located broadcast tower (see figure). This creates a very strong path dependency and makes the network extremely vulnerable to a single point of failure. These networks are also tremendously resource intensive, requiring the deployment and upkeep of many (often redundant) single-purpose signal towers, equipped with specialized and hugely expensive broadcasting equipment.

In contrast, a mesh wireless network allows members of the network to connect directly to each other, thereby building a distributed and decentralized network infrastructure that has no single point of failure. By spreading both network load and failure risk over multiple devices, mesh networks can bypass obstacles like buildings, hills, and trees by using different signal paths, gracefully route route around flaky or overloaded nodes, and provide connectivity to a vast number of network members. Mesh wireless networks are thus fundamentally more reliable than their hub-and-spoke wireless counterparts.

Additionally, a mesh network can be built with a diverse set of hardware: high end carrier class equipment, familiar off-the-shelf home routers, existing computers and laptops, and common mobile devices. The software that powers mesh networks is largely open source, highly flexible and expandable, and freely available from several sources (including OTI). The result is a device-as-infrastructure network model inherently supporting peer-to-peer (mesh) communication while avoiding path dependencies and vendor lock-in.

Closed vs Open Networks

Proprietary or “closed” networks do not communicate with each other. Even in a dynamic mesh system, these closed networks create unconnected wireless islands within a single neighborhood, where users are often forced to overpay for incompatible equipment with only a single manufacturer. The use of proprietary management and control software within these networks further stifles innovation and collaboration among entrepreneurs and programmers by prohibiting local developers from testing out innovative applications and utilities, fixing flaws, or closing security holes.

The success of open Internet technologies demonstrate how open standards and open source provide a foundation for building a platform for innovation to spur local development of new ideas for community applications and a basis for low-cost computing solutions. Open standards lead to interoperability of products, resulting in lower costs to consumers and wireless networks that can scale from a single neighborhood network to an entire country.

Static vs Dynamic Networks

Once a cutting-edge technology, static wireless networks are now seen as difficult to plan, build, manage, and expand. Developers must map out in advance the pathways that network signals will follow to ensure reliable service. This means that if an obstacle — like a growing tree — blocks a user’s connection, or if new users wish to come onto the network, the entire network may need to be reconfigured to enable signals to reach them. It is an inflexible system that is easily disrupted. The result is often an expensive, inefficient network with severe limitations on expansion.

A dynamic wireless network constantly adapts its wireless links to cope with new conditions. It automatically adjusts its pathways to integrate new homes and businesses and provider higher capacity connectivity to a wider area. This kind of network is strengthened and expanded as the subscriber base grows. It changes patterns of use to bypass interference, blockage, or network congestion. Dynamic networks achieve higher resilience and flexibility able to support neighbor-to-neighbor and metro-scale networks with self-healing connections compared to rigid and fragile static networks.

Further Information:

Publications:

“Wireless Networking in the Developing World”:https://wndw.net/ “From The Digital Divide to Digital Excellence: Case Studies on Mesh Networks”:http://newamerica.net/publications/policy/from_the_digital_divide_to_digital_excellence “Rise of the Intranet Era”:http://www.newamerica.net/publications/policy/rise_intranet_era

general_resources/mesh_network_architecture_benefits.txt · Last modified: 2013/11/08 21:42 (external edit)
 
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