Define the wired backbone. If your wireless LAN's users need to
communicate with users at other access points, you need to specify a wired backbone,
such as Ethernet or Token Ring, to provide physical interconnections between access
points. If you have a wired LAN, you can connect the access points to open ports on
your switch or hub.
Define
connectivity software. These are the tools for interfacing devices that
operate on the wireless LAN with host systems. For instance, if you need to reach
applications that run on an AS/400 or Unix box, you'll probably need to specify
terminal emulation software for your handheld devices. Consider using wireless
middleware if high reliability -- or the ability to interface with data located on
multiple, dissimilar host systems -- is required.
Choose products. Consider the products' technical
specifications, such as standards compliance, optional features beyond the scope of the
802.11 standard, price, warranties, and technical support capability.
Verify the design. This includes verifying that the
technologies, configurations, and product selections truly satisfy your requirements.
To do this, you can run simulations and set up a physical prototype.
A simulation uses software models, like
HREF="http://www.opnet.com/products/library/WLAN.htm">Opnet, that artificially
represent an 802.11 network's hardware, software, traffic flows, and utilization. You
can run simulations and check results quickly; days of network activity go by in
minutes of simulation runtime. Simulation tools, however, are generally costly, with
prices in the tens of thousands of dollars. You might be better off hiring a company
that already owns a simulation tool.
Run a physical prototype by constructing and testing part of the system you wish to
verify. You get real results because you're using the actual hardware and software. Be
prepared to reconfigure your prototype as you go. Don't skip this step if you need to
ensure compatibility among 802.11-compliant products from different vendors.
Document the design. As with requirements and other phases of a
system implementation project, you should document the details of the design before you
implement it. Be certain to document schematics, building-layout drawings, and bills of
materials or parts lists.
Once you finish these steps, you'll be ready to procure the components.
Next time, we'll take a close look at configuring an
compliant access point.
