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CTS 108: Useful Wi-Fi Metrics To Track

Which Wi-Fi metrics are worth tracking and what can you do with those metrics?

This episode was sponsored by Metageek

Sponsored by Metageek

Useful Wi-Fi Metrics To Track

Today’s Wi-Fi networks are the main point of access to network resources and have become mission critical service to employees. To monitor the Wi-Fi network, which metrics should you track to show the Wi-Fi network is performing optimally? We list our six useful Wi-Fi metrics worth tracking.

RSSI

  • Most looked at metric
  • Determines the strength of the signal
  • Good to get both from AP and client perspective. Client may hear AP loudly but not the other way around

SNR

  • Indication of signal quality
  • Difference between the signal and noise
  • Example: concert, kids talking over parents

Channel Utilization

  • How busy the channel is
  • Both 802.11 and non-802.11 traffic
  • Congestion and capacity
  • If youre seeing high channel utilization you may need to add more capacity
  • Tells us if CCI is an issue

Data rate

  • Especially useful on the client side
  • Tells us how well the client is able to decode the Rx signal
  • Tells us how the driver is handling data rates

Retry Rate

  • Does it correlate with high channel utilization
  • Are basic data rates too high
  • If you’re seeing too high (10-15%) retry rate look into lowering data rates, look at potential interference, maybe even hidden nodes or devices with bad drivers

Association Time

  • Why would it take a long time to associate
  • Bandsteering could cause long association times because of delayed probe responses
  • Are devices scanning DFS channels
  • Can client and AP hear each other

CTS 102: Capturing Wireless Frames

François and Rowell discuss their experiences capturing wireless frames for analysis and what tools they used to do it.

This episode is sponsored by Metageek

Sponsored by Metageek

Capturing Wireless Frames

It’s one of my favorite things to do. Capture wireless frames anywhere there’s a wireless network present. I know. I’m a boring guy. But I can’t help taking a look. In this episode on capturing wireless frames, we go over our favorite tools and apps which help us solve real world problems.

Why should you capture frames? If you want to learn how wireless works, then you need to start diving into frames. That’s how you’ll learn exactly what you need to know by seeing how it works. It’s perfect for learning any of the CWNP certifications and especially for the CWAP. By looking at wireless frames, you’ll begin seeing how wireless devices and access points talk to each other and acquire the shared medium.

A beacon frame displayed from Wireshark.

A sample beacon frame from Wireshark

Another reason for capturing wireless frames is to perform analysis. There may be an issue that’s hard to solve and requires wireless frame analysis. This could be as simple as finding out a device does not negotiate the same parameters as the BSS. Or maybe you’re trying to find out what could be slowing down wireless for every other device.

It’s the old saying, packets never lie. But in this case, frames never lie!

Screenshot from Metageek Eye P.A.

An example of using Metageek Eye P.A.

You can capture wireless frames on any platform such as MacOS, Windows, and Linux. When it comes to the platform of choice, we prefer to use MacOS. By default, you can place the MacOS wireless adapter in promiscuous mode. This mode is used to capture all frames, even those not destined to the host. By utilizing an app such as Airtool, it’s possible to fine tune a frame capture down to parameters such as the channel, channel width, payload or no payload, etc.

Then with Wireshark, the analysis can be performed.

Mojo Packets Analysis

A section of Mojo Packets analysis.

In the episode, François and I speak about our experiences in using frame analysis. I bring up a situation where Skype calls kept dropping but the issue was really a consumer level device trying to take up most of the airtime. There are other examples also described in the episode.

Here are some screenshots of different applications of frame capture and analysis.

Links and Resources

CTS 081: Wi-Fi Apps for Windows

We couldn’t do our work without the valuable apps used in the Windows operating system. That’s what we’ll discuss in this episode. Wi-Fi apps for Windows.

This episode is brought to you by

Sponsored by Metageek

Here are the Wi-Fi apps for Windows that Rowell and I use regularly when we are working at client sites or for any other Wi-Fi project. We certainly have our favorite apps and there are some we use on special cases but take a look at the list below and let us know what you think in the comments.

Metageek Chanalyzer

  • Spectrum Analysis software (For more, listen to CTS066, CTS039, CTS073)
    • Required a piece of hardware to feed spectrum information to the software
      • Wi-Fi Spy dBx
      • Cisco CleanAir AP (much better resolution)
  • Simple and user friendly interface
    • Different views
      • Waterfall view
      • Current spectrum view
  • Ability to record spectrum analysis
  • Can scan both 2.4GHz and 5GHz bands at the same time (if proper adapter is used)
  • Built-in Wi-Fi network scanner
  • Present channel utilization
  • Link to Chanalyzer

Screenshot from Metageek Chanalyzer

Metageek Eye P.A.

  • A different way to analyze a Wi-Fi network
    • Very visual
  • Ability to capture packets (if proper Wi-Fi adapter is used – Airpcap Nx) and display different valuable statistics
    • How much the airtime is used? By who? You will see how much your neighbours affect you!
    • Compare size of packets with amount of data transfered. Helps to visualize that Wi-Fi generate tons of management traffic
  • Ability to import packet capture taken from other programs (Wireshark, AirTool, CommView…)
  • Ability to see the packets
    • With filter capabilities
  • Great to visualize issue and present to customers
  • Geat to gather statistics on how a Wi-Fi network is performing
  • Side note: Great tool to use to learn more about Wi-Fi
  • Link to Metageek Eye P.A.

Screenshot from Metageek Eye P.A.

Ekahau Site Survey

  • Swiss Army knife of Wi-Fi (for more listen to CTS069, CTS009)
    • Site Survey tool (Design, validation, troubleshooting)
    • Wi-Fi scanner
    • Spectrum Analyzer
    • Complete solution meeting the needs of Wi-Fi Engineers
    • Updated on a regular basis
    • Take advantage of the Wi-Fi community to improve the tool (#ESSRequest)
    • Reference in terms of Wi-Fi design and site survey tool today
  • Looks way way way better than AirMagnet
  • Complete set of features
    • 3D Wi-Fi design
    • Reporting and Reporting customization
    • Spectrum Analyzer
    • macOS version (beta)
  • Link to Ekahau Site Survey

Viewing channel overlap in Ekahau Site Survey

Metageek InSSIDer Office

  • Wireless network scanner
  • See what channels are used by other networks
  • RSSI
  • Data rates
  • Protocol
  • Plug in WiSpy dBx for Chanalyzer lite
  • Link To Metageek InSSIDer Office

Screenshot of Metageek InSSIDer

Savvius Omnipeek

  • Heavy Duty Network Analyzer
    • Use to troubleshoot Wi-Fi networks
  • Capture packets and provide insight on the quality of the network (more than just Wi-Fi)
  • Ability to drill down into the packets
  • Ability to use multiple adapters to captures on multiple channels to analyzer things like roaming behaviours
  • Can be overwhelming at first but very powerful
  • Link to website
  • Video from WLPC2016

Screenshot of Omnipeek

Netsh Tool

Screenshot of Netsh

Some other programs worth talking about

What apps are you using in Windows? Did we miss any?

CTS 080: Wi-Fi Apps for macOS

Let’s face it, we enjoy our Wi-Fi tools and apps. This episode talks about the apps we use in macOS. So if you’re a Mac guy, this episode is for you.

This episode is happily sponsored by Metageek

Sponsored by Metageek

Wi-Fi Apps for macOS

Being a Mac user meant not having enough apps to do your job. As a Wi-Fi professional, we rely on many apps to help get our jobs done. Fortunately, we have developers who hear the cry for professional Wi-Fi apps on macOS. Here’s a list of apps Francois and I use on a daily basis. This is in no particular order.

Wi-Fi Explorer

Great app developed by Adrian Granados who was interviewed back on 007. Double 007! This is an excellent Wi-Fi network scanner that is simple to use and updated regularly. It has built-in search functionality so you can find the network you’re looking for. You have the ability to add different columns to fit your troubleshooting needs and you can see advanced details such as information elements. This is a paid application.

Screenshot of Wi-Fi Explorer

Airtool

Another powerful app from Adrian Granados. It’s a menu bar application capable of capturing Wi-Fi frames using the Mac’s built-in Wi-Fi network card. From the app you select a channel to capture frames from, select the channel width, and you’re off to the races. It can be used with Wireshark, Cloudshark, and Mojo Packets. This is the fastest way to capture frames using a Mac. One of my favorite apps to use. Also, it’s Free!

Screenshot of Airtool

Wi-Fi Signal

Adrian Granados strikes again! This is a menu bar application used to easily check the status of the Wi-Fi network you’re connected to. It can display information such as quality of the received signal, signal in dBm, noise, SNR, and current channel. It can send notifications of when you connect/disconnect to a Wi-Fi network and even if you roam.

Screenshot of Wi-Fi Signal

Debookee

We interviewed the developer, Thomas Baudelet, in episode 70. This is a great app with a wireless module which displays details of Wi-Fi networks, displays statistics such as retry rate and Tx and Rx throughput. This app makes it easy to analyze other clients’ performance. This is a paid app.

Screenshot of Debookee

iPerf

A free application to test throughput of your Wi-Fi network. What else is there to be said!?

Metageek InSSIDer Office (beta)

Currently in beta, Metageek has a macOS application that can scan Wi-Fi networks around you. It contains a search functionality to get through all the networks on the list. If you plug in a WiSpy dBx you can get a lite version of Chanalyzer. This is a paid app.

Screenshot of InSSIDer Office

Terminal/iTerm2

Use this to SSH into your devices. You can build aliases and scripts to help you manage your network efficiently.

TamoSoft Throughput Test

Can operate as a server or a client. The server can be ran from macOS or Windows. The client can operate on macOS, Windows, Android, and iOS. It’s very easy to use and provides a visual throughput tester. You have the ability to set QoS and perform TCP or UDP tests.

Screenshot of TamoSoft Throughput Server

What tools are you using on macOS? Which are your favorite? Let us know in the comments below.

Links and Resources

 

CTS 066: Spectrum Analysis with Joel Crane

Joel Crane is our special guest on CTS and he has a lot of knowledge bombs on spectrum analysis. Be sure to listen to this episode.

Interference. The invisible killer of your spectrum. It creates a terrible user experience and your network is to blame for it. Spectrum analysis is how you’re going to identify what is kicking your Wi-Fi to the side.

I’ve used this process to find issues the users are experiencing. Often times the fault is placed on the WLAN but it is either done unintentionally or on purpose. You will usually find out that there is a misbehaving device or a consumer level hardware causing issues with the WLAN.

In this episode, Rowell and François ask Joel Crane questions about what spectrum analysis is and why is it useful.

Spectrum Analysis with Joel Crane

  • Detecting, identifying, and locating non-WiFi interference
  • Gauging co-channel/adjacent interference
  • Who uses it
  • Cool stuff to know about
  • The troubleshooting process
  • Duty cycle vs. utilization
  • Real-time FFT vs Swept-Tuned

Resources Mentioned

Sample Spectrum Captures

This Week In Wireless