Implementing WLAN Analysis
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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.
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.