Interesting column by UK Wi-Fi gadfly--say that three times fast--Guy Kewney, pointing out a competitive technology to Tropos's new approach: Kewney thinks I was too broad in stating that all Tropos competitors choose to use 5 GHz for backhaul only, where Tropos's new metro-scale mesh system will use 5 GHz as an alternative mesh routing path with dual-radio nodes. He writes that LocustWorld, in operation since 2002, offers similar mesh-over-multiple-radio technologies. And that the firm is ignored because they don't really sell hardware or software; they develop software for reference platforms and sell consulting services.

Because LocustWorld doesn't have salespeople or an obvious US presence in the market--because they're not per se selling a product--I haven't seen any comparisons with their software running on commodity devices against commercial, expensive gear sold by Tropos, BelAir, and others. I don't know whether their approach has been considered by any of the major operators now in the US market. MobilePro has chosen to use Strix gear, EarthLink picked Tropos and Motorola, and MetroFi has stuck with SkyPilot.

It's worth noting that both the commodity devices and the multi-thousand-dollar, multi-radio proprietary hardware mostly use Atheros chips. That's right. The heart is the same. Tropos's VP of engineering Saar Gillai said in an interview earlier in the week that Tropos has put significant effort into building their own radio boards around Atheros chips, while, he asserted, their competitors typically purchase prefab reference design-based boards that Gillai says vary in performance from board to board.

If you look at Defacto Wireless, a partner of LocustWorld that sells Atheros-based mesh nodes in the US that will run LocustWorld's software, they offer single-radio ruggedized external nodes for $700 to $800, which is about a fifth of the list price of a Tropos single-radio node, which Inc. magazine said retails for $3,500.

RoamAD from New Zealand also offers software for fungible Wi-Fi boxes, although they charge license fees for it. Martyn Levy, RoamAD's CEO, told me recently that their mesh approach allows their value-added integrators to choose the best set of Atheros-based hardware, manufacture or purchase it in whatever quantities they want to negotiate, and then install RoamAD's routing gear.

I'll be curious if someone performs the testing necessary to see how RoamAD and LocustWorld stand up to their much-more expensive, proprietary hardware brethren. I have been told by RoamAD and LocustWorld seems to maintain that a large number of nodes using their respective software have been installed worldwide.

But no significant metro-scale operation in the US has been built on either platform, and we're living in the crucible of municipal Wi-Fi right now. RoamAD has a large installation in downtown Perth that's focused on three-dimensional (i.e., tall building) mesh networking, but it's only 20 blocks. Bigger networks are in the works, but not yet announced.