802.11 Topologies Excel in Higher Education
Wi-Fi’s real security risks and rumored performance lags seem to
be small obstacles to its acceptance among institutions of
higher education. With increasing frequency, extending the
campus LAN means going wireless. The topologies are often
similar from campus to campus, applying one and sometimes two of
the IEEE’s 802.11x wireless protocols. Most often, 802.11b is
the standard selected, either as a precursor to the coming
802.11g (with which it is backward compatible) or because it is
so broadly available, having been first on the market. But some
campuses have also chosen 802.11a.
Referred to as WLAN, Wi-Fi, and 802.11x, these wireless
topologies find few roadblocks to implementation among colleges
and universities. In this environment, return on investment
(ROI) is calculated in terms of savings, value, services, and
the investment made in students themselves by enhancing the
learning environment.
Wi-Fi installations also present few physical challenges.
Usually, campus IT departments perform the installations quickly
- sometimes in just a few weeks. Once an institution has
invested in vendor selection and gathered vendor input, there is
little further delay before the proposed WLAN is up and running.
Wireless access points (APs) deliver freedom of movement and
untethered access at about 6 Mbps (adjusting from the advertised
11 Mbps for about 5 Mbps of overhead traffic, which routes and
delivers the payload). Campus constituents seem to be satisfied
with this speed - at least for now.
The following is a brief overview of seven campuses that agreed
to share their wireless stories.
Practical Considerations at Clarion University
The Clarion University library is currently served by a wireless
LAN of 30 APs optimally placed throughout the building. “The
library was recently renovated,” says Michael A. Phillips,
network and communications manager at the university
(mphillips@clarion.edu), “so, as part of that renovation, we
wired it with CAT5e cabling, but we also planned for a wireless
network.”
The five-story structure has adequate wireless coverage
throughout as well as some outdoor access. The WLAN is
interconnected through a dedicated VLAN, set up exclusively for
the wireless network. The infrastructure includes Cisco wireless
access points, a Bluesocket wireless firewall, and Marconi
Ethernet equipment.
Clarion chose the 802.11b standard in part based on price and
availability. Clarion is strongly considering 802.11g for
upgrades, as many campuses are. The 802.11g protocol is not only
backward compatible with 802.11b but is also expected to deliver
on the promise of 54 Mbps, almost five times the speed of
802.11b. (802.11a delivers 54 Mbps but is not compatible with
802.11b or g). The 802.11g standard is expected to be finalized
this year - perhaps as early as this summer - with some
producers like Linksys already rolling out 802.11g products.
What about Clarion’s wireless hardware?
“We’re not using the standard, ‘off-the-shelf’ APs from Cisco
with the integrated antennas,” says Phillips. Rather, Clarion is
using a model from the Cisco 350 Series that adds the option of
an external antenna. The Clarion library’s drop-ceiling tiles
were retrofitted with integrated antennas from Armstrong as part
of the networking. “We wanted uniform coverage cosmetically
consistent with the rest of the building,” says Phillips.
Wireless ceiling tiles allow Clarion more control over where the
radio signal travels. In dense areas such as Clarion’s library,
this helps keep any one AP from bearing the load for the whole
network. The wireless ceiling tiles keep the service seamlessly
invisible to its users.
Accommodating Students at RIT
Rochester Institute of Technology (RIT) prepared for the
possibility of an upgrade in 802.11 protocols and APs while
deploying 802.11b. By installing two Ethernet jacks at every AP
location during the 802.11b installation, RIT made ready to
carry two standards to ease migration. Should 802.11a or g look
inviting, RIT can test the additional protocol and APs while
maintaining 802.11b coverage.
For RIT, Wi-Fi is an extension of a flat, single network on a
single subnet. “We expect that as wireless usage grows, we are
going to run into the typical problems that are present on a
flat, single network. That will dictate the need to change the
topology,” says Patrick Saeva, program manager for the IT
department at RIT (pjsits@rit.edu). For now, this simple flat
topology guarantees seamless roaming for campus constituents.
RIT plans eventually to consider additional wireless services
beyond surfing and basic Internet use. As traditional return on
investment concerns (and financing) are not obstacles, only a
strong demand for expanded services will determine
implementation.
Calculating ROI is a difficult process. RIT’s decision to invest
in wireless services was based on whether it would help the
students. A similar philosophy guides the decision-making
process at other educational institutions.
Flexibility at Syracuse University
“We bought APs that will accommodate either 802.11a or g,” says
Lee Badman, network engineer at Syracuse University
(lhbadman@syr.edu). With a solid 802.11b base, Syracuse would
lean toward advancing to 802.11g when the need for greater speed
arises. The 802.11g standard provides the same speeds as 802.11a
but within the 2.4 GHz ISM band. (Residing in the 2.4 band is
the commonality between 802.11g and b that makes g backward
compatible with b.)
The wireless topology is a neutral, demilitarized-zone network
that sits outside the university’s main network. It exists on
one subnet across the campus. A gateway/firewall provides
protected access. “It’s considered untrusted, and the
gateway/firewall separates the users from the rest of the
campus,” says Badman.
Syracuse’s wireless LAN has presented no problems in the areas o
f speed, performance, and reliability. Security risks are
mitigated by the value of having wireless LAN service and by the
separation from other campus networks. Badman expects that there
will always be some security risks.
Dual-Mode Solution at UNC
The University of Northern Colorado uses Vernier Networks’ IS
6000 (an integrated control server and access manager) to
authenticate students on its 802.11a and b networks. The
wireless network is separated from the campus’s wired network.
Following a site survey (performed by NetCom International)
Vernier was selected along with Cisco for the APs and the
wireless virtual private network (VPN).
Asked why UNC uses both 802.11a and b, Jeanette Van Galder,
director of administrative information technology
(jeanetter.vangalderl@unco.edu), said, “While the 802.11b
network interface cards [NICs] are more prevalent in the
consumer market, we wanted a dual-mode solution for individuals
requiring higher speeds and additional capacity.”
Segmentation from the primary network is accomplished with
VLANs. UNC uses Cisco’s VPN for faculty and staff for data
encryption and for drive mappings to the current active
directory, says Van Galder.
UNC installed in-house based on NetCom’s findings for the
optimal placement of APs. It also installed its own wireless
security using not only VPN but also LDAP. Van Galder says that
although they use the network only for WLAN, VoIP could be
considered among added services.
Productivity and efficiency improvements are a big part of UNC’s
ROI. Because students are sharing files directly between
laptops, server loads are decreasing. Students are spending more
time on the network and are more productive.
Meeting Many Needs at OIT
“Basic service set [BSS] is the current layout for Oregon
Institute of Technology [OIT] wireless networking. Each AP is
connected to a wired Ethernet jack,” says Agnes Box,
telecommunications coordinator, information technology systems,
OIT (boxa@oit.edu). As with other 802.11 topologies, there is
some overlap of coverage by APs in order to ensure sufficient
coverage everywhere.
OIT used products from vendors Cisco and Avaya (formerly
Lucent), already familiar from their use at other Oregon
University campuses. Specifically, these are the Avaya Wireless
Access Point-3 Ps with power-injected Ethernet, silver and gold
wireless cards, and antennas from Avaya, which were once the
WaveLAN products.
Criteria used for evaluating 802.11b solutions included the
number of users connected at any one time, the ease of
migration, and scalability. OIT will likely migrate to 802.11g
to meet eventual demands for greater speed. Campus topology will
probably evolve to extended service set (ESS) when this happens.
With ESS, overlapping broadcast rings will provide roaming from
building to building. As a natural enhancement to the network,
the corrugated metal buildings at OIT act as antennas, sending a
strong Wi-Fi signal throughout the buildings.
An Integrated System at Collegis/Salt Lake Community College
Larry Maughan’s team at Collegis/Salt Lake Community College
went to Proactive Network Management Corporation “for
engineering, coordination, and support in integrating [wireless]
into the existing network,” says Maughan, director of netcomm
(larry.maughan@slcc.edu). Collegis/Salt Lake is now implementing
VLANs as a solution to conflicts between APs. Future services
will expand to include PDAs (in trial mode now) and soft phones.
As it has for other institutions, 802.11b have been very
reliable for Collegis/Salt Lake. The Cisco LEAP security product
manages security, and all users are required to log on via an
account on the active directory. The only problem seems to arise
from weeding out bad APs. The process will be greatly unburdened
by the adoption of the Cisco Wireless LAN Solutions Engine
(WLSE), which will allow remote identification, location,
troubleshooting and configuration of APs. Until this solution,
Collegis/Salt Lake has been searching for bad APs manually by
touring the suspect coverage area with wireless laptops upon
notification of the problem to technical support.
John Dunn and Proactive Network Management Corporation helped
Maughan and his group with their wireless deployment. Together
they set up 802.11b coverage for 13 sites including four major
campuses - every room in every building. “We used Cisco ACS
products for the authentication, and then it was tied back into
its closest switch where it also receives its power,” says John
Dunn, president of Proactive Network Management (john@pnmc.com).
Maughan and his team did most of the design, and the two
organizations worked together on the site survey and
implementations.
Seeking Security at Bridgewater State
Using Enterasys R2 APs and Cisco switches, director of
telecommunications Patrick Cronin (pcronin@bridgew.edu) and the
Bridgewater State College team set up 802.11a. As the topology
evolves from a simple routed network, Cronin plans for “some
sort of solution to segment the collision domains without
requiring an additional login as you roam.” Bridgewater is
considering Bluesocket, Vernier, and other solutions.
As far as security goes, “Right now we don’t allow access to our
administrative systems from the wireless network,” says Cronin.
However, as Bridgewater comes to rely more and more on the
wireless network, more critical data will be transferred over
it, and security will become more of an issue.
Just as many other institutions today, Bridgewater is
conservative about plans for services in addition to WLAN. It
has taken a glance at 802.11b phones.
Enterasys helped Cronin set up Bridgewater’s 802.11a network.
When asked about the topology, John-Paul Gorsky, director,
wireless product line, at Enterasys (gorsky@enterasys.com),
said, “The typical topology you will see is buildings, or floors
in buildings, connecting back to the intermediate distribution
frame on the particular floor.” The wireless topology depends a
lot on what the wired topology is - whether the wired networks
on each floor are individual subnets, for example. Roaming works
best on the same subnet.
Conclusion
There are a variety of ways to approach implementation of 802.11
protocols, and a selection of hardware solutions is available.
Flexibility, keeping your options open for the future, seems to
be the secret of success.
Sidebar
The 802.11 standard and the FCC
The FCC doesn’t require licenses for any of the 802.11 protocols
and so these are freely used.
“Since the FCC does not require licenses for use of the 2.4 GHz
or the 5.15-5.35 and 5.725-5.875 GHz spectrum bands, companies
may develop products and services according to business plans
that they think will best suit users - subscription, free or
whatever,” says Anita Wallgren, attorney at Sidley, Austin,
Brown, and Wood, LLP (awallgren@sidley.com).
Wallgren notes that the FCC does, however, stipulate that
companies obtain Part 15 certification for the APs and
receivers. This is in order to meet power and performance
specifications. The unlicensed spectrum model for 802.11 will
likely continue due in large part to its level of success.
