Two wireless start-ups, Airespace and Aruba have launched in Europe - and you might be forgiven for confusing the two. As well as both starting with A, they both focus on RF self-calibration, security and real-time applications, such as voice. They also both make the bold claim that they can sell their wireless kit, even to enterprises that don't want any wireless networking on the premises - as a means of prevention.

"We lock the air," said Keerti Melkote, vice president of product management at Aruba Wireless Systems. "We block rogue access points and hackers to protect your air space." The service is an extension of the rogue detection that most enterprise wireless systems do, and Airespace does it too: "Customers with a 'no wireless' policy use us to prevent wireless networks being set up," said Alan Cohen, Airespace's marketing vice president.

Even if the enterprise resolutely refuses to adopt Wi-Fi, this new phenomenon could be a big market for the enterprise Wi-Fi vendors, since this kind of air monitoring will be the only way IT managers can prevent people putting in their own access points. A former colleague of Cohen's at Cisco kept an access point under a sweater for two years, he said, and in companies where there is regular monitoring for access points, rogue users rapidly find out when to turn their systems off.

Both the A-teams base their prevention model on the RF management features of their access points (AireWave Director, and Aruba's RF Director). Both of them monitor the air for other Wi-Fi systems - a feature which also allows them to be self-optimising and self-healing, cutting back their signals to prevent overlaps. This kind of self-managing Wi-Fi system is the answer to our Wi-Fi Jeremiah's assertion that once Wi-Fi takes off there will be too much interference between access points. "With RF management, the more overlap the better," said Melkote

Both companies are strong on voice: "We have an average system latency of 3 milliseconds," said Airespace's Cohen, who claims his access points can each support up to 14 voice calls at a time.

The trick with voice is secure roaming, with quick handovers however, and that is the first sign of an argument between them, because they use different technologies. Airespace uses Layer 2 tunnelling, while Aruba uses the mobile IP standard with the GRE cellular signalling protocol.

Cohen reckons his tunnels are fast, while Aruba's Mobile IP "is a huge mistake, because it needs the backbone routers to be reconfigured." Melkote says, "We have addressed the integration issues by using a proxy." Operating at Layer 3 lets Aruba apply different quality of service standards to several streams from one machine (so you can browse and phone at the same time for instance). Cohen admits he can't do this (yet).

Deep down, the two distinguish themselves by the stress they put on different parts of the system, with Airespace playing down the switch aspect: "We don't think this is about switching," said Cohen. "We design from the RF up."

For his part, Melkote dismisses the idea that RF is the crucial part of the system: "We come from a network switch background," he said. "For Airespace, the switch is an afterthought. But it is not about Ethernet switching, it's about Wi-Fi switching." He believes that important as RF management is, it will soon be part of the access point chipset and even commodity access points will have standard hooks for RF management tools. "If you try to say what a genius you are at RF management it is a dead story."

In 18 months, NetGear access points will be able to operate in "enterprise mode", letting wireless switches adjust their RF features, according to Melkote

"If Aruba thinks RF management is a commodity, why don't they do it as well as we do," returned Cohen. "We're happy to do a side by side RF test any day with Aruba.

On distribution and sales, the two companies return to similarity. Both sell indirectly and have set up distributors in Europe (in the UK, go to React Technologies for Aruba) and both have customers to talk about (telco reseller IMTech is working with Airespace and furniture vendor Sharkey is working with Aruba).

On the prices quoted, Aruba's look cheaper, but buyers will need to carefully investigate comparable features. Airespace quotes $11,000 for a 24 port switch; while the Aruba's newly launched 24 port system starts at 6,500 euros, but much of the software is extra, taking the likely price up to 9,000 euros.