WLAN quality Assurance (WQA)

Posted by:

Another goody from Finland

It seems that a group of former Nokia engineers, accustomed as they were to ensuring reliability and providing accountability over wireless wide area networks, saw the need to provide that same level of quality over wireless local area networks. And so the company 7signal was formed and a new age of Wireless Quality Assurance (WQA) for WiFi was launched.

Two ways to go

7signal ( ) offers two solutions to the problem of WLAN quality assurance. They are 7signal Sapphire and 7signal Site Miner. Sapphire is a suite of hardware and software components that can be installed into the enterprise and used to provide continuous monitoring and reporting on the performance health of the WLAN. Site Miner is a portable, troubleshooting kit, which can be setup quickly and easily in a client enterprise and accessed remotely to diagnose difficult WLAN problems. Either of these products allows a WLAN administrator/engineer to perform continuous network environmental auditing, including spectrum analysis, automatic measuring and tracking of end-to-end WLAN performance, determination of optimization recommendations, alarm triggering and notifications when problem thresholds have been exceeded, all of which reduces an organization’s operational costs (OPEX), resulting in an improved return-on-investment (ROI).

Like a WIPS, but for performance

The 7signal products are similar to an overlay WIPs, in that they use dedicated always-on sensors to gather and store statistics on wireless activity and characteristics in a relational database, where admins can review the information through a intuitive, graphical reporting console. But instead of security information, 7signal focuses on performance measurements, using metrics designed specifically to evaluate the health and suitability of the WLAN for all types of user applications. Both the 7signal Sapphire and Site Miner products contain a Carat management and database server with an integrated graphical measurement and reporting tool, one or more high-performance, 802.11n-compliant “Eye” sensors, and a Sonar surrogate QoS server, which provides a source of QoS-type traffic for active measurements to and from the LAN.

With Site Miner, all of the 7signal applications arrive pre-installed on two Linux laptops, one for the Carat server and another for the Sonar server. For Sapphire, it is recommended that the same 7signal applications be permanently installed on a robust server or virtual machine platform. All of the features are accessible from the Linux GUI interface and there is no need to access the command line (unless you prefer to), except if you intend to assign static IP addresses.

All seeing “Eye”

Sapphire uses special monitoring sensors, which because they use powerful sectoral antenna technology, can monitor large coverage areas, which may include several APs. These sensors are equipped to perform both passive and active testing of the WLAN and tunnel the real-time results directly to the management server through an encrypted connection. The proprietary management protocol also allows protected administrative access from non-secure, remote locations.

Automated passive AND active testing

Passive testing consists of standard, live, protocol and spectral capturing, but during active tests, the Eye sensor operates like a typical QoS client device. It associates individually to the network’s APs and performs various test functions, some of which include QoS communications through to the Sonar server. The Sonar server is used to emulate a customer’s production QoS servers without distracting them from their primary duties or putting additional strain on the network’s hardware. Together the Eye sensor and Sonar server can initiate uplink and downlink exercises, while measuring simulated voice calls, file transfers, and many other live-session procedures. Since the Sonar server is located on the wired LAN, the resulting metrics can indicate the health and performance of the entire network, not just that of the WiFi segment. The data from these tests are forwarded through the encrypted connection to the Carat management server to be classified within a DB2 database for further analysis. The test scripts are easily customized.

Closer to 200

The Sapphire and Site Miner systems can gather constant performance data from well over 100 key performance indicators (KPI) and categorize them for review within the graphical reporting engine. The KPI’s, which are gathered from active testing, include L1-L4 Access Success and Failures (18 tests), L2 – L7 Session Retainability (12 tests), Cell Handover Quality (6 tests), Application Quality (9 tests), Round Trip Time (4 tests), IP Traffic Behavior (6 tests), and Radio Signal Quality (9 tests). Passive testing consists of monitoring the live network traffic and identifying KPI’s from Access Point Availability (4 indicators), Access Point Radio Signal Quality (9 indicators), Access Point Security (4 indicators), AP and Client Traffic (19 indicators), and Spectrum Analysis (3 indicators).

Easy button for WiFi QoS

These KPI’s are converted to graphical reports and charts that intuitively show Radio Attach Success Rates, VOIP Test Success Rates, MOS Uplink and Downlink scores, AP Beacon Availability, Client Signal Levels and Client SNRs, to name just a few. The graphical reporting interface even includes a “traffic light” view with intuitive color coding that allows instant recognition of “Normal, Warning, and Trouble” events. Since the reporting engine is browser-based, remote administrators can login securely and view the performance displays through an Internet connection. The graphical reports can also be output to text, CSV, or PDF formats.

A CWNE’s best friend

The major difference between the 7signal Sapphire suite and the Site Miner is that Site Miner is a fully packaged portable and “ready-to-ship” troubleshooting kit. Site Miner is intended for temporary placement into an existing infrastructure in order to allow a WLAN engineer to monitor and diagnose problems or determine the suitability of an existing WLAN in order to support high performance services. The Site Miner kit can also be used to validate new QoS platforms following an installation or upgrade. With the Site Miner equipment setup in a customer’s location, it is possible for the network engineer to remotely monitor the health and performance characteristics of the live WLAN during normal operations. By using the numerous reports available over a relatively short period, it is possible for the engineer to more accurately diagnose network problems and suggest surgical corrections to the infrastructure. The complete Site Miner kit, which includes the Carat and Sonar laptops, two Eye sensors, cables, and power bricks arrive housed in a custom-foamed Pelican 1650 case and ready to deploy. This makes a perfect addition to a WLAN engineer’s standard troubleshooting, site survey, and penetration testing kits.

Real WiFi SLAs possible

Although 7signal products are only available in Europe at this time, the company plans to expand into North America within the next year or two. The addition of a Site Miner kit gives the WLAN engineer the best tools available to isolate and mitigate WLAN performance issues. The permanent installation of a Sapphire system allows the WLAN admin to monitor and proactively correct developing performance issues in advance of that dreaded voice call from the CTO. With these tools and proper training, the promise of Wireless Quality Assurance can be offered and even guaranteed through Service Level Agreements (SLAs), which are normal in the broadband world, but have been decidedly scarce in the WiFi realm. Would you want to bet your reputation on the peculiarities of WiFi? With 7signal the odds become more favorable.


About the Author:

Scott Williams serves as the managing partner and co-founder of Wireless Training & Solutions.


  1. Training Solutions  September 10, 2012

    Oh wireless training, it will be very interesting for me because i have never hear this type of technology, this article is unique for me, thanks for posting…!

  2. Chang Blount  September 29, 2012

    Hello.This post was really motivating, particularly since I was looking for thoughts on this topic last Saturday.

  3. Betti  October 2, 2012

    Taking the oevrievw, this post hits the spot