jake snyder

CTS 114: Automate or Die

Automation and programming is making its way into the WLAN engineer’s daily work life. Jake Snyder joins the show to provide his experience and use cases.

CTS episode with Jake Snyder.

Automate or Die

We’ve seen automation take over the server and networking world. Wi-Fi is the last to fully embrace programming, APIs, and automation. It’s slowly making it’s way. There are now vendors which support a full API which makes the capabilities go far beyond what we see in a dashboard.

Jake Snyder joins CTS to talk about how he got started with Python, his programming language of choice nowadays, and how he uses what he has learned to make processes more efficient. For networking, it’s mostly Python.

What are some of the use cases available to show the power of automation and programming? It’s possible to automate the most mundane tasks which can help give back many hours. An example would be automating the upgrade of a network. It could take months for a fairly large installation. But with the help of Python it could take less than a month. Turning a multi-month long project into one month is a huge return on investment. The engineer can now focus on other projects with that saved time.

Sample code from Mojo Networks

Sample of code from Mojo Networks

Jake takes this to more advanced levels by comparing his design to the installation. He automates a process to tell him which APs may have been installed incorrectly. The validation survey data such as AP locations, their transmit power, and channel can be directly compared to the design. This saves a lot of time spent analyzing data and finding out that access points were installed incorrectly.

Another example of Wi-Fi automation can be seen in security. In Jake’s home private network, he uses automates a process of a rogue device abusing his Guest Network. When identified, he receives a message in Slack and simultaneously pulls that device’s information from his firewall. The automated process moves the client to a proxy where he is able to inject a frame onto the device’s web browser displaying the person’s credentials captured over the network. A quick way to get them off the Wi-Fi right away! While Jake brings this example from his home network, it shows what can be accomplished.

There’s so much more that can be done but only a few examples which we talk about on the show.

How To Get Started?

There are quite a few resources available for the beginning programmer. Jake Snyder and Ryan Adzima did a class at WLPC 2018 teaching the basics of Python using Learn Python 3 The Hard Way, a resource Jake highly recommends. They showed attendees how to parse data out of an Ekahau file using Python.

There are Python classes catered to network engineers. This is the best way to see relation into the day job as a general Python class may not help you really see what can be done on the network. Just check out the Python for Network Engineers course from Kirk Byers.

Then start looking at the APIs provided by your Wi-Fi vendors such as Mojo Networks, Mist, and Meraki.

Links And Resources

CTS 057: Hallway Design

In this episode I want to talk about Hallway Design or lack of it. This was inspired by a #WIFIQ that Lee Badman threw out there. I’ll tell you now, I don’t like hallway design. What is Hallway Design?

In a #WIFIQ thread, Jake Snyder said, “There is a difference between sticking APs in the hallway and hallway design.” And that’s true. He makes a very good point. The former is the act of randomly placing them in the hallway in hopes that you get fantastic coverage for the users in the rooms.

Negatives of Hallway Wi-Fi

  • Low SNR
  • Coverage holes
  • Negative RRM effect
  • Not designed for capacity
  • No one working in the hallway
  • Transmit power set at the highest if manually configuring
  • Channel overlap
  • Poor roaming decisions
  • Lots of omnidirectional APs in the hallway

Designing Wi-Fi With Hallway In Mind

  • Plan on the number of APs that will be placed in hallway
    • Important to help facilitate roaming
    • Signal propagates far in the hallway
  • Lower transmit power or use thresholds
    • Number of APs that can hear each other will have a negative effect
  • Consider RRM in the design
    • Transmit power levels
    • Set thresholds – don’t allow the AP to go too high or too low
  • Place APs where the users are
    • Higher SNR
    • Better data rates
  • Plan for roaming
    • Wi-Fi calling now available, users will walk out of their workspace
  • Use building obstacles to help attenuate the signal
  • Use a proper channel plan

Links and Resources

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