CTS 052: How To Validate Wi-Fi Infrastructure

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)

Links and Resources

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About the Author
Rowell, CWNE #210, is a network engineer in Higher-Ed. He enjoys working with wireless networking technologies and loves to share and engage with the community. You can connect with him on Twitter, LinkedIn, and Facebook.

2 comments on CTS 052: How To Validate Wi-Fi Infrastructure

  1. Jhotly Debrosse says:

    Hi Rowell/Francois,

    First off, great work on this podcast that gave me a lot of insight to help to my journey in wlan space.

    My name is Jhotly Debrosse and I’m from Montreal, Quebec, Canada. I’ve been working in the IT industry for quite sometime now. By day I’m a cloud automation specialist and during my spare time (if any) I’m giving back to a nonprofit org infra to be wlan certified 🙂 with all the best practices I’ve learn from you and the wlan community. More informations to come!

    I’ve been using Ekahau Site Survey a couple year back to test the waters and I was impress but I didn’t have all the knowledge that I have right now thanks to you guys. It’s a bit overwhelming I will admit but the community on twitter is awesome to help us.

    In the coming days, I will get my hand on the CWNA book but in the meantime I’ll be listening again to yo u guys and WiFiNigel podcasts.

    Until we talk again…

    1. Rowell says:

      Hi Jhotley, thanks for leaving a comment!

      I think it’s great that you’re contributing to the non-profit community 🙂

      Let us know if you have any questions with CWNA. You’re in good hands there and continue to listen to Nigel’s podcast as they are full of good information.

      Thanks for listening to our podcast as well. I look forward to hearing your progress!

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