AirMagnet has launched Vo-Fi Analyzer, software that can analyze a wireless LAN's fitness to carry an enterprise's VoIP calls. With the software running on a notebook PC, a network architect can walk around the places where employees work and detect weak coverage spots, packet latency that could cause calls to break up or drop, and even problems in an IP PBX.

Voice over wireless LAN is just getting on to enterprises' to-do lists, mostly in organisations that are already using wired VoIP, according to Ron Howell, a senior network architect at AT&T who helps customers design and build their internal networks. Some companies are building wireless LANs and looking for ways to get the most out of them, and in many buildings a WiFi network can provide better mobile voice coverage than can cellular networks, Howell said. AT&T uses the Vo-Fi Analyzer to track actual calls, simulate heavy voice traffic and see how well the network handles the tasks.

"They all want to know it's reliable," Howell said. "Essentially, we try to break the network." Depending on the how well a wireless LAN was designed and what brand of equipment was used, performance can vary, he said. AT&T recommends enterprises keep the software to continue monitoring their network.

FarPoint Group analyst Craig Mathias thinks enterprise desktop phones are on the way out and the main barrier to putting voice on the wireless LAN is a shortage of combined cellular and WiFi phones. There's no reason why most wireless LANs couldn't handle voice, but there is a need for tools to monitor how well it works, he said. In addition to good network design, network managers have to track various kinds of interference. AirMagnet is one of several companies, including WildPackets and VeriWave, that are working in this area, Mathias said.

The software provides visibility into call performance that wasn't available before, Howell said. It lets the AT&T engineers quickly find the cause of a problem.