The deployment of Wi-Fi throughout municipalities has led to the development of specialized “mesh” Wi-Fi routers that mount on light poles and traffic lights to provide coverage in outdoor areas.  This equipment, offered by vendors such as Tropos, BelAir, Cisco, Motorola and Strix, provide a Wi-Fi interface to users while also linking together (“meshing”) using vendor-proprietary protocols. If one particular mesh node can’t connect to the backbone of the network via a backhaul radio, that mesh node will connect to a nearby mesh node in order to hop packets through the network. This architecture allows the deployment of Wi-Fi throughout large municipalities by simply attaching the mesh nodes to light poles and supplying electrical power to them.

The mesh protocols go well beyond what the 802.11 /Wi-Fi standards define. As a result, interoperability (the meshing protocols) between mesh nodes from different vendors doesn’t exist. Thus, the 802.11 Working Group kicked off Task Group S in July 2004 to develop the 802.11s standard for mesh networking. 802.11s will provide topology discovery and path selection, something beyond the scope of traditional 802.11 access points. As of April 2007, the current state of the draft 802.11s standard is the D1.02 document, with ratification likely in 2008

There’s no indication yet which Wi-Fi mesh vendors will support 802.11s. In order to avoid a level playing field in the market, mesh vendors will likely always have proprietary routing enhancements beyond what 802.11s will provide. If you want to take full advantage of these additional functions, similar to 802.11b/g access points, then you’ll still need to use mesh nodes from the same vendor regardless of the adoption of 802.11s.