validation survey Archives

CTS 052: How To Validate Wi-Fi Infrastructure

October 9, 2016 Rowell 00:49:41 2 Comments

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
Validate
- 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:

Coverage
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.

Spectrum Analysis

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.

Packet Capture

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)