Dave Bailey
IT Week
30 October 2007

The last time I tried to connect to a large wireless network that was supposed to cater for a large number of people was at the 2006 GSM conference. After a fair few tries at connecting, I had to resort to the old wired network. Wi-Fi networks should be able to handle the kind of heavy workloads you get at a major trade show. But can they?

That was a question put to me by a company formed five years ago called Extricom. One of Extricom's head honchos, an ex-Motorola radio frequency (RF) engineer, said that the IEEE 802.11 wireless standard was devised for a scenario where a single wireless access point (AP) has multiple clients connecting to it. Would an IEEE body composed of radio-frequency engineers have let the 802.11 standard through? Extricom thinks not.

The 802.11 standard works for households because they typically have only one AP or wireless router, but it struggles when it comes to enterprise deployments featuring multiple APs across large campuses. Add the need to cater for mobility, and current systems really do begin to creak.

For me the term mobility conjures up images of employees wandering around the office with dual-mode handsets, unconcerned about where the best signal is to be had. In this scenario, moving out of range of one AP and into range of another, triggers a seamless signal transfer. Seamless to me means that you can't detect whether there was ever a handoff at all, and you can continue talking, oblivious to what the technology is doing in the background.

At the 2006 GSM show, however, I was shown such a handoff using a dual-mode phone and seamless it wasn't. It was three seconds before I could speak again. Extricom believes it has the technology to get around 802.11's mobility shortcomings.

Its system gives "blanket" coverage on a single channel, rather than the multiple ones used by other vendors, and its "APs" consist of a radio receiver and transmitter that connect back to a central controller. Other vendors use APs as discrete units, whereas Extricom uses its devices to create a "wireless continuum", where you associate to the network rather than to a specific AP. This approach has the potential to make mobility over large areas far less problematic as no handoffs are required. An added bonus is that the technology does away with the need for admins to carry out all those tiresome wireless network site surveys, which are essential when deploying other vendors' kit.

Extricom has recently signed an agreement with BT, which means this small, independent company could make some big household names vulnerable to being on the wrong end of a handoff themselves.

The original version of this article can be found in ITWeek Magazine. It can be accessed by clicking here .