University says multimode WLANs ease operations

According to at least one organization, the availability of dual-band, multimode wireless LAN access points significantly eases site surveys and other RF management tasks.

Brian Jenkins, network and technical services manager at Frostburg State University in Frostburg, Md., recounts how the blueprints for two new buildings on campus initially called for 802.11a-only deployments. However, with the advent of 802.11a/b/g gear, the technology plan changed.

“As the job was nearing completion, we fell onto the ‘tech bubble’ when the WLAN switch appliances and a/b/g APs were coming out,” explains Jenkins.

Frostburg chose its infrastructure from start-up Airespace, which offers APs in both the 2.4-GHz frequency for 802.11b and 11g connectivity and in 802.11a’s 5-GHz band, plus a “switch” for centralized management and monitoring. The three non-overlapping channels in the 2.4-GHz band plus 13 in the 5-GHz band supply enough channels to keep interference at bay.

This works in the context of the Airespace gear because the company’s APs and wireless switch support automated RF capabilities, such as dynamic channel selection and interference detection and avoidance.

To fully leverage the multichannel strategy, user clients must support dual-band, multimode a/b or a/g or a/b/g connections, which Jenkins says is what the university recommends to students, faculty and staff.

Interestingly, Airespace initially launched a combined wireless/wired switch; more recently, it added a wireless-only appliance option, when it discovered that some customers were already comfortable with their wired Ethernet switches. Frostburg, for example, uses the new Airespace 4100 wireless-only appliance plugged into Extreme Networks wired Ethernet switches.

Jenkins says a pen-and-paper site survey was originally done for the new buildings – before any bricks were laid – presuming an 802.11a infrastructure. Then Airespace came in with dual-band, multimode products. Frostburg followed the original placement plan, but in May installed 48 Airespace 1200 multimode APs instead 802.11a-only products and two Airespace 4100 appliances, each with 24 ports.

“We brought the products online and could immediately see where an appliance was telling certain APs to back off and was strengthening signals in other places [to optimize performance],” Jenkins says.

He says he found just one area where he didn’t have coverage in a room built of concrete block up through the ceiling. “So we just took an AP from an area that was saturated and just moved it to that room,” he says.