The Network World Virtual Showdown on WLAN switches that brought six vendors together in a weeklong debate resulted in a flood of information, which highlights product differences in key areas such as security, network management, architectures and pricing.

"There's a lot of material to work through, but it's valuable for showing readers what those differences are," says Craig Mathias, principal at Farpoint Group, a wireless consulting firm that teamed with Network World on the showdown. It featured Airespace, Aruba Wireless Networks, Chantry Networks, Extreme Networks, Symbol Technologies and Trapeze Networks.

Some of the most extensive posting was over the benefits/drawbacks of Layer 3 vs. Layer 2 functionality. Vendors like Chantry, which touts its product as a "wireless router," said Layer 3 can accommodate any type of existing network topology, run over any kind of local or long-distance connection and provide the kind of subnet mobility that WLAN VoIP will demand.

"A Layer 3 solution does not require any intrusive network configuration to the existing wired network or complex network design to enable features such as multi-subnet roaming," Chantry wrote.

Extreme, among others, countered that demand for Layer 3 functions among enterprise users is minimal, at least for now, in part because customers are unwilling to deploy proprietary Layer 3 roaming and tunneling features. Instead, customers are more interested in isolating WLAN traffic from wireline traffic via easy-to-configure virtual LANs.

"It's not practical for customers to mix and match wired and wireless users on the same subnet until a complete security framework is well understood and deployed," Extreme wrote. "Standards need to be put in place for seamless security and mobility [at Layer 3] before customers should jump on Layer 3 mobility."

Aruba described one of the more-elaborate roaming schemes: It created extensions to the RFS-2002 Mobile IP standard, typically used for mobility by cellular carriers. Aruba also created what it calls a "Proxy Mobile IP [stack] with Layer 2 extensions," which is loaded on the Aruba switch and "mimics the function of a mobile station, eliminating the need for code on the WLAN clients." A Proxy Dynamic Host Configuration Protocol feature, also on the switch, ensures the client maintains its address across subnets.

VoIP over WLAN

Vendors insisted that running IP voice traffic over WLANs is the next big thing. Mathias wanted more specifics: "What facilities do you have in your products to support voice while simultaneously providing acceptable data throughput?" he asked.

Aruba's reply began with voice security, saying VoIP phones "can't be effectively authenticated on wireless networks because there is no way to pass credentials into the infrastructure." Aruba's solution is to create what it calls "stateful voice flow classification technology," which identifies voice traffic and enforces security restrictions on these devices and the traffic they create.

Aruba said one result of this capability is the network then can give priority to voice traffic by applying quality-of-service (QoS) policies, as long as the underlying IP network supports this.