Triple Play Test Indicates IT Issues
March 28, 2005
Independent analysis by the UNH InterOperability Lab shows that, while Wi-Fi infrastructure is maturing, the simplest of issues can bring any corporate WLAN to its knees.
Last week, the University of New Hampshire InterOperability Laboratory (UNH-IOL) held its first multi-vendor tests of what it calls the "triple play" for enterprises: use of data, voice and video on the same wireless network infrastructure. The week-long experimentation session in a simulated environment looked at everything from quality of service to secure access, and how various things can impact WLAN performance.
"A lot of these tests have been done in pieces and various forms, disjointed... We wanted to see if various protocols on wireless LANs caused calls to drop, affecting this or that," says Gerard Goubert, manager of the UNH-IOL wireless and VOX (Voice over Anything) consortiums. "We wanted to mix it all up."
Among the findings still being tabulated by the lab for a future white paper was that much of the test equipment was able to handle multiple connections from Wi-Fi-based phone handsets to an AP, as many as 12 to 16 simultaneously, when previously the best was 7 to 8. However, different types of test equipment indicated different numbers, even in the same tests with the same systems.
"Those companies are looking at the discrepancies," says Goubert.Mixed mode networks, with both 54Mbps 802.11g and the slower 11Mbps 802.11b, both running in the 2.4GHz radio band, already are known to have issues that cause 11g to slow down. UNH-IOL noticed this again (especially with voice, which at the moment is predominantly 11b only), and says that sometimes mixed mode systems had worse performance than straight 802.11b infrastructure.
The event brought together various divisions of the 32,000 square foot, non-profit UNH-IOL to work together. The various groups do testing for members year-round. UNH-IOL is also an authorized "pre-certification" test center for the Wi-Fi Alliance, meaning vendors go to them to make sure products are interoperable before taking the final plunge with the Alliance's main test facilities around the world.
Several companies participated in the testing, including many big names like Cisco, Dell, and IBM; wireless switch vendor Aruba Networks; testing companies like Azimuth, Ixia, Empirix, VeriWave; and others.
"The thing we were interested in is, 'Is the network ready to handle this?'" says Goubert. "It's pretty well ready, but there's a tricky setup; things have to fall into place." He says this isn't always the fault of one issue -- for example, the voice service. "A protocol you thought had nothing to do with voice over Wi-Fi can have an effect."
The conclusion so far: "You have to know your products well and test them often," Goubet says. "Code builds can affect things. Segregate voice from data and don't have blinders on, thinking that wired won't affect wireless.... an IT guy must know all the protocols on the network and know how they work."
The white paper on last week's test is expected by the time of the next Networld+Interop show, scheduled for the first week of May in Las Vegas. UNH-IOL intends to hold this triple-play test period on a regular basis in the future.