Cheat Sheet: Wireless mesh networking

Go on then, mesh networking – why should I care? What's so exciting?
A mesh network is essentially a series of nodes – wireless access points typically mesh routers but also laptops, PDAs and the like – which route data to each other.

There are two types of mesh networks, one where every node is connected to every other node and another, known as a partial mesh network, where each node is only connected to some of the others in the network. To get to a base station, users simply create a path by 'hopping' between nodes.

And what's so good about that then?
It's all about creating a really flexible network. In a traditional mesh network, nodes will constantly be communicating with each other, so should any one of the nodes fail, data is simply routed around it. Equally, as true mesh networks are self organising, if a new node appears it should immediately become assimilated into the mesh.

And what radio technology would I need for one of these mesh networks?
Theoretically, any radio technology – or a combination of several - can be used in mesh networking but wi-fi is the most commonly used.

Haven't people been banging on about mesh for years?
Yes but according to those who monitor such things, mesh networking may be reaching maturity in the not too distant future. Analysts ABI Research, for example, recently predicted that cable multi-service operators may start launching commercial trials in 12 to 18 months' time in the US.

However, ABI Research paints a grimmer picture of mesh networking's future in Europe, where 3G has more of a hold and new players have better access to incumbents' networks.

But where would I expect to find a mesh network?
Mesh networks have to date really been used in two main situations: to cover campus type environments and as co-operative metropolitan networks, where participants own and look after their own equipment. Creating such a mesh is one way for rural communities to make internet access more affordable.

Mesh networks are also handy for building temporary networks in places like festivals or conferences, or even for the military or emergency services on an ad hoc basis. Mesh networks could also find favour as a means of dodging costs associated with rolling out extra Ethernet in SMEs or universities.

Another area where mesh networking could flourish is in warehouses or other wi-fi unfriendly locations.

So who's getting involved in this mesh malarkey then? Anyone I know?
Microsoft already has its researchers looking into mesh networking, while Motorola is one of the big names to get on the bandwagon of late with the launch of its Motomesh product. According to Motorola, a number of cities in the US are deploying it.

On this side of the pond, LocustWorld is the main proponent and has hundreds of users.

What else should I know then?
Like most technologies, a few concerns remain. As with traditional wi-fi before it, wireless mesh networking raises questions of security and privacy. For co-operative or municipal networks there's also the issue of making sure everyone gets their fair share of the bandwidth.

Also, in some cases, networks can degrade the greater the number of 'hops' made and the larger the distances between nodes. Conversely, in other situations, the network's performance can actually be improved by balancing traffic and routing it around congested nodes.