For A Strategy On Wireless Networking
- Adopted By ITS Advisory Committee October
Wireless LAN technology has been available for approximately four
years, it has become increasingly popular in the last eighteen months
as hardware prices have begun to drop to commodity levels. Wireless
NICs are approaching $100, and enterprise-grade access points can
be purchased for approximately $1,000. The current standard, known
as 802.11b provides 11 megabit/sec bandwidth over a coverage
area of roughly 200 ft. depending upon building structure. This
is roughly equivalent to10 megabit/second wired hubs (under optimum
conditions) and is adequate for light usage such as email and browsing.
A new standard, 802.11a, providing 52 megabit/sec bandwidth
is expected to be available soon albeit at higher cost and with
a smaller coverage area. 802.11a access points and client
cards are incompatible with 802.11b devices. A third standard,
802.11g, has recently been approved that provides 22 megabit/sec
bandwidth and is backward compatible with 802.11b. Wireless
LAN technology is basically a short-range service and is incompatible
with long-range cellular data services which operate at substantially
lower speeds. In all three standards the bandwidth is shared among
connected machines, providing significantly lower performance than
switched wire connections, which dedicate 10mb or 100mb to each
envisions potentially significant demand for wireless network service
at Yale, due to the convenience of mobility for campus laptop/PDA
users and the trend toward providing wireless transceivers as standard
equipment in such devices.
believes that the primary goal at this point should be to lay the
foundation for a reliable wireless infrastructure that meets current
needs while maintaining enough flexibility to incorporate improvements
in the technology, and provide seamless growth to campus-wide coverage.
In anticipation of improvements, investment in the technology should
attempt to meet, but not encourage, demand.
constitutes a reliable wireless infrastructure?
Well-engineered installation of the access points including proper
channel assignment and avoidance of airspace conflicts.
Uniform support, maintenance, and documentation of wireless service
across the campus.
Security. Common policy for access to the wireless network, encryption
employed to the extent possible and desired, clear understanding
for users of the risks involved.
Tracking improvements to the technology (better security, higher
bandwidths, etc.) and devising strategy for incorporation into
the Yale infrastructure.
respects the challenges and tasks are similar to those faced years
ago with the emergence of wired LANs. However, the imperative for
uniformity across a wireless infrastructure across the campus is even
stronger since the primary purpose is client mobility.
Standardization of access point hardware and designation of compatible
client cards. This is rapidly converging to full interoperability,
but problems may remain with older cards, driver versions, etc.
implementation of wireless LANs presents several possible threats
to a reliable infrastructure:
Overlap in radio coverage of access points installed by departments
in close proximity may cause significant impairments to performance.
These would be unpredictable; a wireless LAN that has been working
for months might suddenly and inexplicably bog down when the lab
upstairs installs a new access point.
While it is certainly possible to work these problems out, resolutions
would require cooperation and technical analysis that is beyond
the capabilities of some departments.
Random use of security measures may inadvertently provide access
to unauthorized individuals. In some locations, this could be
by non-Yale users physically outside of buildings. All traffic
between an access point and its users shares the same wavelength,
so traffic that is not encrypted may be easily "sniffed".
Uncoordinated configuration of access points and/or incompatibilities
between different manufacturers access points and client cards
could result in the inability of wireless users to obtain
seamless connectivity and adequate performance across the campus.
steps can Yale take to ensure a reliable, robust wireless infrastructure?
Some Universities have forbidden the connection of wireless systems
by departments or, to varying degrees, deemed the wireless "airspace"
to be under central authority. While this approach may work elsewhere,
restrictive or punitive solutions typically do not work at Yale
and can become an issue unto themselves. A far better approach for
us would be to provide positive incentives to utilize the central
University infrastructure. The incentives are reliable function,
cost avoidance and convenience.
these points in mind, ITS proposes the following strategy for Campus
Wireless LAN Service at Yale. As the technology is evolving rapidly,
this strategy should be reviewed periodically until wireless technology
ITS will begin to phase in wireless access in public spaces throughout
the University within the current budget. Initial deployment would
be in public conference rooms (those that may be used by any University
department at no charge). In order to avoid over investment
in current technology, ITS proposes to provide service primarily
to areas with significant existing demand, i.e. high presence
of laptops and PDAs.
While all machines using the network must pay the standard access
charges, there will not be an additional charge for wireless service
for those machines already paying for access to the wired network.
ITS will configure, install, monitor, and maintain wireless service
for departments, labs, etc. for the acquisition/installation cost
of the access point. As demand grows, ITS will re-design the buildings
wireless infrastructure, ensuring coverage for all interested
parties. In order to make this an attractive alternative to do-it-yourself
installations, ITS will consider using low-cost devices where
they would meet the requirement, in accordance with DNO established
hardware standardization preferences, and also offer to create
building or area-wide proposals and broker the cost among the
ITS will not attempt to prohibit departments or groups from providing
their own wireless services providing they follow ITS technical
standards that will ensure proper performance and reduce the risk
of interference with other wireless installations or impairments
to the Campus Network Backbone. Under the University Acceptable
Use Policy, ITS is empowered to disconnect wireless installations
that impair the Campus Network Backbone, ITS-provided wireless
service, or other departmental wireless services. Local providers
will need to agree that if subsequent demand justified service
throughout the building, they would decommission their wireless
service in exchange for access to the ITS-provided service.