In this episode, I talk with Francois Verges of Semfio Networks about how to validate the Wi-Fi infrastructure.
Validating a Wi-Fi network involves many steps. This is not isolated to a new deployment but also to an existing Wi-Fi network. Francois and I talk about what to validate, look out for, and what resources are available to assist on the job.
Validate Physical Installation
- Walk through the facility
- AP installation
- Antenna orientation
- With the customer
- Telco room location
Post Deployment Survey
- Use your survey laptop and try to use a business critical business device as well (VoIP phone, handheld scanner…)
- Connect to the infrastructure. Use the most business critical SSID.
- Use Ping or iPerf to test connection, roaming, throughput.
- Things to look at while performing the exit survey:
- What band is the survey laptop using?
- What band is the client device using?
- Am I roaming as expected
- RSSI of both your laptop survey and the client device
- If you use ESS, you can also connect 1 or 2 dBx antenna to perform a parallel spectrum analysis. (Detect noise and major interferences)
Things to look at after the survey:
- Channel distribution / Channel re-use
- See if some Tx Power need to be adjusted
- See if some radios need to be disabled (2.4GHz)
- See if more 5GHz channels are needed
- Making sure that all the configured channels are being used.
- Study both bands: 2.4GHz is usually where you will find the most external interferences
- Stay still at one location. If you see something unusual, move around to pin point the exact location of the source. (might not be easy). – Plan for a little extra time.
- Get a better idea of the RF environment (using Eye P.A.). Thing to look at:
- Retry rates
- Channel airtime utilization
- Data rates
- How the neighbours can be affecting some channels
- Being able to see more advanced radio configurations such as:
- data rates
- AP capabilities
- Client capabilities (Big one)
- Being to spot unusual behaviours
- Being able to troubleshoot some client issues
Analyze Client Behavior and Configuration
- Make sure all the client devices of the same model have the same Wi-Fi NIC drivers
- Make sure all the client devices of the same model have the same Wi-Fi configurations
- Make sure they manage to connect to the Wi-Fi network (Check delays, does it take a long time to connect?)
Perform Functional Validation Testing
- Grab a client device, roam around the facility (especially where the device will be used)
- Validate how the client roams
- Validate on what band the client connect to
- Try to ping the application server and see if you lose any pings (make sure it does not affect production)
- Validate voice quality if it’s VoIP
- Validate throughput if the requirements need it (try to use the same applications as the one what will be used on the Wi-Fi)
Links and Resources
- Jake Snyder blog
- CTS 039 – When and How To Use Spectrum Analysis
- Mike Albano – Clients
- Ekahau Site Survey
- Metageek Chanalyzer and Eye P.A.
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