Most schools that deploy or consider deploying wireless LAN technology, do
it to extend high-speed Internet access to classrooms. Schools in New York City,
though, are taking a slightly different approach.
The New York City Department of Education (NYCDE)
began its wireless initiative, part of the much larger Project Connect,
last year. By September 2002 it had installed wireless networks in 200 schools
— mainly using Aironet 350 series access points from Cisco Systems. It will install an additional
300 schools by September 2003.
The difference in NYC is that the schools already have wired Ethernet drops
in the classrooms being equipped with Wi-Fi. The wireless networks were installed
not to avoid pulling cable, but to provide maximum scalability and ensure that
every student in the room could be connected to the Net at the same time.
"So if the Chancellor [the head of the department, Joel I. Klein,] decided
to give wireless devices to every child in the fourth grade tomorrow,"
says NYCDE director of information technology Joe Eaione, "we won’t have
any performance problems."
How likely is it that will happen? Not very, perhaps, but Eaione points out
that the computer population in the New York school system is exploding. At
one point last year, 1,000 new computers were being turned on each week. There
are already 150,000 for 1.2 million students, a ratio of about one to eight.
"We see that [ratio] decreasing and decreasing," Eaione says. "We’re
looking at using more and more wireless devices for instruction. It’s one of
our big pushes. The people who are giving funding want to see computers at the
end of [network] drops. Despite the funding cuts, this is definitely still a
priroity."
The department isn’t just installing one access point for every five or six
classrooms, as in most school deployments. It’s installing an access point in
every classroom. Each room is its own Wi-Fi microcell.
"We wanted to ensure maximum flexibility," says Eaione.
Eaione, who taught in the New York school system himself before taking over
the IT department, and still teaches part-time at the university level, explains
the department’s philosophy of supporting high-tech teaching methods to the
nth degree.
"We wanted the ability for someone to walk into a classroom and do a guest
talk or a demonstration and be able to plug in [to a wired port] — because
they won’t necessarily have a Wi-Fi card — and the students can all be connected
at the same time."
"We don’t want teachers worrying about technology. If I’m the teacher,
I want the technology to enhance me, not be an impediment. That’s why we think
we need both [wired and wireless connectivity]."
The goal is eventually to equip every classroom in every school in the city
— that’s 60,000 to 70,000 rooms in over 1,200 schools. "Obviously it will
take a little while to do," Eaione says. However, virtually every school
in the system already has high-speed Internet access and most have wired Ethernet
drops in at least some classrooms.
Capital for this massive project has come in large part from the federal government
E-rate (Education Rate or Universal
Service Fund for Schools and Libraries) program. The program in effect provides
schools with deeply discounted prices on Internet and telecom services and computer
equipment.
The level of E-rate discount is based on each school’s participation in free
and reduced-price lunch programs. The NYCDE has concentrated so far on schools
in the "90-percent poverty" range which qualify for the highest E-rate
discounts. In other words, the poorest schools in the city are getting wireless
classroom networks first — a nice reversal of the usual form.
While the objectives for the NYCDE wireless project are a little different
than in most jurisdictions, the department is still reaping some of the more
customary benefits. The only other way to achieve the same level of connectivity
would be to install switches and routers in each classroom, but that would have
been prohibitively expensive.
"We estimate that a wireless deployment can be done in a school at as
little as one third the cost of a hard-wired solution," Eaione says.
"But that’s not referring to the classical savings over putting a [wired]
drop in every classroom," chief wireless architect Jim Anilowski hastens
to point out. "We wouldn’t even consider putting wireless in a school that
didn’t already have a wired Ethernet drop."
The NYCDE’s unique approach required a unique network architecture. Each classroom
is a self-contained wireless extension to the school’s wired network. With many
if not most wireless LANs, designers look for maximum coverage from each access
point. Here, designers had to find ways to limit coverage to just one
room. It wasn’t always easy.
"In order to achieve a microcell structure, we initially thought that
using a 0-gain antenna with an access point capable of reducing RF output power
would have been sufficient," Eaione explains.
The department’s choice of access points was partly based on this requirement.
The Cisco 350 series units have detachable antennas and configurable RF power.
There were other reasons for choosing the Cisco units as well. They’re "plenum
rated" (fire retardant and toxic emission rated for use in air vents).
They also support Power over Ethernet (PoE) and come with intelligent power
switches, eliminating the need for plug-in transformers in the classroom. This
usually one source of savings over wired approaches.
The initial microcell design didn’t entirely work, however. The problem was
coverage "splashing" out of one room and interfering with the networks
in adjacent rooms, either beside or above or below — classrooms are packed
close together in many of the schools. Sometimes coverage splashed outside the
school, causing security concerns.
"We ultimately had to use 9db attenuators in line with all antennas in
an effort to produce an appropriately sized microcell structure," Eaione
explains.
The department also abandoned attempts to use 802.11b for outdoor bridges between
school buildings. It found that the bridges inevitably interfered with the classroom
networks. Now it’s investigating using 802.11a which uses 5.2GHz U-NII-band
spectrum and thus won’t interfere with 2.4GHz 802.11b.
Despite these set-backs, the implementation has gone surprisingly smoothly.
This is partly thanks to the careful preparation and design work, Eaione says.
"We spent a considerable amount of time planning every detail of the architecture
and implementation. For example, we obtained floor plans for every location
and digitized them prior to deployment, giving the surveyors a method to document
where each access point was going to be located."
The department is also now experimenting with voice over WLAN at its headquarters
at Tweed Hall in Manhattan, though it’s not apparent it will take this experiment
much further in the near term.
While the NYCDE is cleary at the leading edge of Wi-Fi in K-12 education, it
is surprisingly reticent about pedagogical results so far. In response to our
questions, we received only this apple pie & motherhood statement:
"We believe the wireless networking solution will add unlimited flexibility
and usability compared to previously tethered computers, giving our educators
a great new tool to help teach our children more creatively and efficiently."
It may be there are in fact few if any immediate pay-backs. This is a very
long-term infrastructure project, which may not deliver a return until somebody
decides to give every fourth-grader a wireless laptop.
