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The good, the bad, and the unknown about mesh

Dec 05, 20052 mins
Cellular NetworksNetwork SecurityWi-Fi

* Mesh: Points to ponder

It seems I just got started on my musings about using mesh Wi-Fi for public network services last week, and suddenly I had reached the end of my allotted word count. So here are few other points of interest on this topic:

* For public safety purposes, Wi-Fi offers good bandwidth. But by itself, it isn’t an optimum technology for speeding down the street after suspects at 100 miles an hour. Check that your provider has built in fast roaming and handoff into its mesh routing algorithm and at what speeds mobile mesh devices can communicate, both with one another and back to stationary access points. If these capabilities aren’t present, you may also need special tracking software at the back end and client/server mobility software from IBM, Ecutel, NetMotion Wireless, Padcom or other “session-persistence” vendor.

For more static scenarios, such as a crime scene or fire, Wi-Fi holds more promise. Start-up PacketHop, for example, contends that it gets around the whole infrastructure interference and overload issue during an emergency by outfitting all public safety emergency responders with mesh software that turns their Wi-Fi devices into instant but temporary local Wi-Fi mesh networks that can operate with or without a Wi-Fi access point. Members of the ad hoc group are both clients and backbone devices, communicating video and whiteboard drawings to one another of exactly where personnel are needed.

* Some Wi-Fi mesh vendors support slots for WiMAX (which supports QoS in the standard and will run in licensed bands) and the 4.9 GHz band, which has been set aside for public safety applications. A couple questions here: Which network operators can get 2.5 GHz licenses? Sprint Nextel owns most of the 2.5 GHz spectrum for which WiMAX equipment is initially being built in the U.S. And won’t the shift to 4.9 GHz blow the economies of scale and interoperability benefits that Wi-Fi has already established?

Note that early WiMAX equipment is also being built for the 3.5 GHz band for regions outside the U.S., and Intel is lobbying in Washington to get slices of 3.650 GHz set aside in North America for WiMAX. No report on its success so far, but equipment designed for 3.5 GHz should also work in 3.650 GHz, according to Intel.