Fixed Wireless Technology

Wireless LAN Tools Part 4: Monitoring and Reporting — continued

by Lisa Phifer VP Core Competence, Inc. [August 17, 2004]

Usage reporting and trend analysis
WLAN analyzers can help you keep tabs on network activity over longer periods of time by crunching monitored traffic to track and store traffic statistics. Long-term traffic observation, analysis, and reporting capabilities vary quite a bit, ranging from basic periodic reports to history databases that support extensive built-in reports and ad hoc queries. Here are just a few examples:

• This TamoSoft CommView panel can be used to generate a periodic traffic report in CSV or HTML format. An example web report is shown here. Report options control how frequently that report is written during packet capture, and the traffic counts to be included in each scheduled report, such as byte/packet rates for each WLAN channel, protocol, and sender MAC or IP address. Periodic reports like this can be handy for look-back viewing and as input to spreadsheets and other traffic analysis tools.
  
  
• This Network General Sniffer Wireless panel can be used to create History Samples. Each configured Sample tracks a single defined metric, like bandwidth utilization, error rates, or the number of Probe, Authentication, Association, Deauthentication, or Disassociation requests per second. Samples continue to be recorded as long as the analyzer is running. Graphed or tabular results can be viewed/printed from the Sniffer console at any time, or exported for further analysis.
  
  
• Network Instruments Observer Suite includes a web server that enables traffic history database browsing by authorized administrators from any location. After logging into this server with a username and password, administrators can use a variety of built-in reports to view and analyze historical data in different ways, over different time periods, to spot growth in utilization or errors before they turn into problems. Data collection can run continuously on the Observer server, but you'll want to choose a sampling interval that strikes a good balance between storage requirements and report detail.
  
  

If historical data is recorded with sufficient granularity, raw counters can be sliced and diced in many different ways to better understand network, device, application, and user behavior. For example, this Sniffer Wireless report provides an analysis of server response time, broken down by application type (web, ftp, pop, smtp, etc.).

This pair of Observer Network Trend viewers show how the same underlying history data can be used to generate statistics pertaining to individual APs, IP hosts, or even TCP sessions. Here again, you'll probably want to look beyond WLAN traffic, examining end-to-end traffic for an overall perspective on how your network is being utilized.

Conclusion
In this series, we have covered quite a bit of ground—and yet, we barely scratched the surface of the many WLAN analyzers illustrated here. Protocol analyzers are a bit like the proverbial Swiss Army Knife. You'll probably spend most of your time using just a few indispensable, well-worn tools. But as you explore further, you'll find that your WLAN analyzer includes many additional tools, the true purpose of which may not be apparent until you read the instruction manual or try to use them. So spend a little quality time digging into your favorite WLAN analyzer—the next time something mysterious happens to your WLAN, you'll be better prepared to spot and decipher the clues.