In the "old days," wireless LANs (WLANs) were primarily only supporting
lower-end, wireless bar code applications in warehouses and
retail stores. These types of applications don’t require much performance, and
they often aren’t very complex. Everything seemed to work fairly well, except
for an occasional coverage issue. Most of these systems employed radio cards
and access points from the same vendor, so even interoperability problems were
kept to a minimum. As a result, there wasn’t much need for analysis of the older
wireless systems.
Today, however, enterprises are deploying larger, more elaborate WLANs that
spread throughout an entire enterprise and support a multitude of applications.
In addition to common wireless bar code applications, companies are now equipping
their workforce with wireless devices for checking e-mail, browsing the Web,
communicating via telephone, and interacting with corporate applications. In
many cases, wireless users are accessing applications both within the confines
of the enterprise and through public hotspots. This really complicates matters!
Applications require greater performance, which means that administrators must
fine-tune the network. In addition, devices from multiple vendors on the same
network occasionally cause pesky interoperability issues. Consequently, companies
deploying WLANs today need a capability of performing WLAN analysis to perform
troubleshooting and ensure the network operates efficiently.
Applying Analysis
Analysis includes the inspection and assessment of the WLAN to find root causes
of problems. With the use of the right tools, analysts
can measure both protocol and RF characteristics of the WLAN, interpret results,
and offer recommendations on how to resolve problems.
The following stages of deployment can strongly realize the benefits of WLAN
analysis:
- System design. The use of analysis at this point reduces risks, especially
when implementing unfamiliar or untried solutions. For example, a company
deploying a voice over WLAN system should setup a test network and carry out
performance and interoperability testing before installing the systems in
an operational setting. - RF Site surveys. Analysis also plays a significant role when performing
a RF site survey. The amplitude and noise measurements taken can lead analysts
to choosing the optimum location for installing the access points for adequate
coverage and determining whether RF
interference may cause performance issues. - Acceptance testing. After installing a WLAN, a company should include
analysis as part of the acceptance testing of the system. Analysis of the
coverage, performance, security, and interoperability test results should
indicate satisfactory compliance with system requirements. - Continual monitoring. Throughout the life of the WLAN, the physical
environment will change as users move walls, desks, and other items that alter
the propagation of radio waves. Thus, the company should proactively measure
and analyze signal strengths throughout the facility to ensure that resulting
coverage holes don’t cause problems. - Troubleshooting problems. Sometimes users experience issues using
the network, and support staff must then perform troubleshooting to solve
the problem. Careful analysis of both RF and protocol behavior is often necessary
to solve issues regarding improper coverage, interoperability issues, and
performance problems.
In order to become proficient at WLAN analysis, consider completing the Certified
Wireless Analysis Professional (CWAP) independent certification program
offered by Planet3 Wireless. [Disclosure: I’m a member of the CWNP Advisory Board for
Planet3.]
Also, stay tuned — We’ll be exploring wireless LAN analysis tools, techniques,
and real world examples in future tutorials.
Jim Geier provides independent consulting services to companies developing
and deploying wireless network solutions. He is the author of the book, Wireless
LANs.
