Despite relatively limited revenue growth for vendors - caused by steep drops in per unit pricing - the wireless LAN market is growing like crazy. Unit sales continue to grow at a double digit pace.\u00a0 More than half of the enterprises we surveyed recently either had WLAN equipment in place, or were planning to have it within a year. As WLANs proliferate, however, many enterprises and public venues face an issue: how to provide secured, policy-driven access to different groups of end users.Despite relatively limited revenue growth for vendors - caused by steep drops in per unit pricing - the\u00a0wireless LAN\u00a0market is growing like crazy. Unit sales continue to grow at a double digit pace.\u00a0 More than half of the enterprises we surveyed recently either had WLAN equipment in place, or were planning to have it within a year. As WLANs proliferate, however, many enterprises and public venues face an issue: how to provide secured, policy-driven access to different groups of end users.Some enterprises and venues have taken the approach of deploying separate WLAN infrastructures for separate groups of users\u00a0- for example, an airport might have one network established for airline personnel, and a separate network providing hot spot access to passengers. This approach can work but can be expensive\u00a0- and it requires a cooperative approach (in terms of site survey and channel selection) to reduce interference between the networks.Another approach to this problem is being offered by\u00a0Chantry Networks, a start-up focused on Layer 3 WLANs. Chantry\u2019s BeaconWorks product line has been designed around the concept that WLANs can be virtualized by the centralized Layer 3 router. A single WLAN infrastructure could therefore support a wide variety of users simultaneously, eliminating inter-network interference while still supporting strong\u00a0security. The BeaconWorks system can simultaneously support different authentication systems, different billing systems and even different IP addressing schemes for each virtual WLAN within the overall network.Chantry\u2019s first marquee deployment of this new technology is being trialed today in a large (over \u00bd million square foot) convention center. The owners of the convention center saw three distinct groups of \u201ccustomers\u201d for WLAN solutions:*\u00a0Conference exhibitors who traditionally paid for wired Ethernet connections to the convention center\u2019s broadband access during shows.*\u00a0Conference attendees looking for quick hot spot access to e-mail and the Web.*\u00a0Convention center employees (and tenant company employees) requiring high-speed network access.Using a single physical wireless infrastructure to provide secured virtual WLANs was an attractive solution for this convention center, from both cost and revenue perspectives.On the cost side, the variable nature of the convention floor layout made wired Ethernet connections a labor and technician-intensive task. Typically, each conference held at the center required a different floor layout.\u00a0 Booth sizes and locations were also variable, requiring timely re-routing of Ethernet cabling for every event. The new virtualized WLAN, after the initial site survey and installation, basically requires only software modifications to accommodate new customers.On the revenue side, the convention center has been able to charge up to $100 per day per exhibitor for access to the broadband network. With the addition of hot spot services for conference attendees, the convention center can easily add a new revenue stream - considering that hot spot operators may charge up to $8 or $10 a day for unlimited access.But these applications are not the most interesting being offered in this convention center environment. This convention center had an existing cordless PBX system in place for convention center employee use\u00a0- a system that was being obsoleted by its manufacturer. Rather than upgrade to a newer wireless PBX system, the convention center chose to migrate internal voice traffic to an 802.11 VoIP handset system. Chantry\u2019s virtual WLAN supports this by providing policies ensuring proper packet routing and\u00a0quality\u00a0of service\u00a0for the wireless voice-over-IP (VoIP) phones.This application may become even more compelling in the near future, as Wi-Fi begins to appear in mobile phones. A convention center operator could offer a VoIP service for convention attendees, either as a lower-cost alternative to traditional mobile minutes or in conjunction with a mobile operator as an easy way of extending coverage within the convention center without requiring the installation of more cellular microcells.Convention centers are a great example of where virtual WLANs make sense\u00a0- who hasn\u2019t been stuck inside one of those monstrous buildings trying to get a cell signal or needing to send a quick e-mail? But they are far from the only example. Chantry, for instance, is close to announcing its first hospital customer, which deploys one virtual WLAN for nurses and doctors to provide HIPAA-ready secure connections to handheld devices; while others are established for administration, visitors and even patients who just can\u2019t say no to e-mail.In the end, virtual WLANs may do for public wireless access what VPNs have done for the Internet\u00a0- take a \u201csomewhat scary-to-the-IT-manager\u201d system and make it part of the core network.