Jim Gallagher, telecommunications manager for Framingham State College in Massachusetts, is learning his lessons in wireless LAN deployment.
In 1997, the college began discussing ways to address the growing demand for computer lab seats and the use of technology in the classroom. The IT department enrolled in a wireless laptop pilot in the fall semester of 1998, after it was decided that a wireless LAN was preferable to spending US$200,000 to convert an existing classroom into a 25-seat computer lab.
Four years later, the initial pilot of 80 laptops used in five courses has graduated into a requirement that all incoming 2002 students use a wireless laptop.
To meet that commitment, the college upgraded its infrastructure, boosting Internet bandwidth from two T-1s to a fractional DS-3, and replacing older 10/100M bit/sec closet switches with Enterasys Networks Inc. E-1 Matrix switches that have Gigabit Ethernet ports.
The college also migrated from about 30 of its Proxim prestandard units to more than 100 new 802.11b standard access points from Enterasys. Most of the RoamAbout R2 wireless access points are located on the ceiling exterior, and others, hidden behind ceiling panels, are equipped with Enterasys Range Extender antennas.
All access points feed in to an Enterasys power unit adapter that connects to the new E-1 closet switches. Traffic is then Gigabit up-linked to an Enterasys ER-16 Xpedition core switch. The Xpedition switch interfaces with a Cisco 2600 router for Internet access and with the fractional DS-3 interface that connects to the campus network’s Fore ATM switch.
There are no outdoor access points on campus. Yet in nice weather the quad area swarms with students sitting with wireless laptops and walking with lids up, fingering commands on screens barely visible in the brightness of the day as connectivity bleeds out from several buildings that wall in the open space. Tucked among rolling hills away from highway traffic, 3,100 students hike tarred pathways that are cloistered by a mix of century-old, red brick buildings and modern cement constructions.
Because the access points follow the 802.11b standard, students can use any vendor’s client card. More than 800 college-owned laptops used by the faculty and students are equipped with cards from Lucent. The college also is offering a deal on Gateway and IBM laptops, which the IT department will support.
Today, Framingham State’s wireless-LAN connectivity is available in all but one building, which is being renovated. The network supports 1,550 laptops and 67 faculty members teaching 113 laptop-facilitated courses. By 2005, all students on campus will be required to have a wireless laptop.
Gallagher says the tricky part of a wireless deployment is getting the coverage right. “There’s no getting 100% quality coverage because lots of things can interfere with the wireless signal,” he says, “It all depends on where you are in relation to the signal. If the laptop is turned in a different direction it may get a better signal, like using your cell phone.”
Gallagher has found that the quality of the wireless signal varies per device, per location, and that certain interference affects reception. The number of access points needed depends on the amount of open space and coverage required, and on a building’s construction. For example, wood and glass let the signal pass through, but the signal gets diminished if passed through concrete with embedded steel rods.
Also, different types of metal can deflect the wireless signal, such as an elevator shaft or a metal walk-in safe. Even different laptop antennae