200 episodes

A weekly podcast about wireless network engineering. Wireless topics on education, wireless design, tips, interviews with other wireless engineers, tech news about wireless, and the products we configure. A podcast for any wireless professional or enthusiast.

Clear To Send: Wireless Network Engineering Rowell Dionicio and François Vergès

    • Tech News

A weekly podcast about wireless network engineering. Wireless topics on education, wireless design, tips, interviews with other wireless engineers, tech news about wireless, and the products we configure. A podcast for any wireless professional or enthusiast.

    CTS 209: Python & Wi-Fi

    CTS 209: Python & Wi-Fi


    François wins 2020 Content Contribution of the Year at WLPC from Wi-Fi Awards

    2020 Content Contribution of the Year Award…Francois Verges! Congratulations @VergesFrancois! pic.twitter.com/Qd3c4R8dvE— The WiFi Awards (@thewifiawards) February 21, 2020

    Other winners:

    * David Coleman – Lifetime Achievement Award

    2020 Lifetime Achievement Award…David Coleman! Congratulations @mistermultipath! pic.twitter.com/QuMqAAV6iq— The WiFi Awards (@thewifiawards) February 21, 2020

    * Lariana Liu – Rookie of the Year

    2020 Rookie of the Year Award…Lariana Liu! Congratulations @LarianaLuy! pic.twitter.com/L4KxubVFKp— The WiFi Awards (@thewifiawards) February 21, 2020

    * Ekahau – Innovation of the Year Award

    2020 Innovation of the Year Award…Ekahau Connect! Congratulations @ekahau! pic.twitter.com/Izhq72Isql— The WiFi Awards (@thewifiawards) February 21, 2020

    * Wi-Fi Explorer – Product of the Year Award

    2020 Product of the Year Award….Wi-Fi Explorer! Congratulations @adriangranados and @wifiexplorer! pic.twitter.com/vIRPGVpHKS— The WiFi Awards (@thewifiawards) February 21, 2020

    * Cisco – Company Leadership of the Year Award

    2020 Company Leadership of the Year Award….Cisco! Congratulations @CiscoChampion and @Cisco pic.twitter.com/dfXuyfZwsh— The WiFi Awards (@thewifiawards) February 21, 2020

    Meraki Releases New Wi-Fi 6 APs

    * MR36* MR46* MR56

    Broadcom Tests 6 GHz

    Python and Wi-Fi

    Last episode we talked about APIs at an introductory level. APIs are great to get information from wifi systems.

    • 51 min
    CTS 208: Introduction to APIs

    CTS 208: Introduction to APIs

    Application Programming Interface: communication protocol or interface used to interact between different pieces of software.

    In networking, you could have an API available to interact between a Wireless Controller and a script coded by the network admin.

    APIs make it very easy to interact with our networking equipment to configure, operate and monitor them.

    In the networking world, these API communications are often established over the HTTPS protocol and are categorized as RESTful APIs. It stands for REpresentational State Transfer. It is a very popular API framework for web services built on HTTP.

    REST is popular because it is fast, simple, scalable and easy to work with.

    Why use an API?

    * Custom dashboards* Automation* Installs* Configuration* Testing* Troubleshooting

    How can I use an API?

    Vendors usually provide extensive API documentation that will tell you how to use them and which data to expect. Sometimes, you have to enable this access (Meraki).

    You can then use applications such as Postman that will help you to design your API calls. 

    Communications are secured and will require some sort of authorization (using a token or API Key). This key will be referenced in every request via a request header.

    Methods (API Calls)

    * GET: returns the value of a resource or a list of resources (Ex: get a list of online APs)* PUT: adds a new resource (Ex: create a new site)* POST: updates a resource (EX: updating the name of an AP)* DELETE: remove a resource (Ex: removing a user)

    Responses – Status and Error Codes

    You will get a response from your API calls. These responses use the standard HTTP status codes:

    * 400: Bad Request* 401: Unauthorized* 403: Forbidden* 404: Not found* 429: Too Many Requests* 500: Internal Server Error* 503: Service Unavailable

    If everything goes well, you should receive a 200 status code as well as the response to your query (if it was a GET query). This response is generally organized with the JSON format. It becomes easier to read and parse it in a script.

    This format can also be specified in the headers: Content-Type: application/json

    Important Things to consider

    * Limitation of number of calls* 5 calls per second for Meraki* 5000 calls per hour for Mist (to validate)

    Sample Scripts

    Rowell’s Script

    import json
    import requests
    site_id = ''
    url = "https://api.mist.com/api/v1/sites/{}/wlans".format(site_id)
    headers = {
    'Authorization': 'Basic '
    response = requests.request("GET", url, headers=headers)
    r = json.loads(response.text)
    for wlans in r:
    wlan_name = wlans['ssid']
    wlan_enabled = str(wlans['enabled'])
    wlan_vlan = str(wlans['vlan_id'])
    print("SSID: " + wlan_name, "\t Enabled: " + wlan_enabled, "\t VLAN: " + wlan_vlan )

    Sample Output

    % python3 get_wlans.py
    SSID: D-NET Enabled: True VLAN: 2
    SSID: CTS Enabled: True VLAN: 2

    François’ Script

    #!/usr/bin/env python3
    import time
    import json
    import requests

    def main():
    org_id = ''
    site_id = ''
    token = ''

    • 35 min
    CTS207: The New CWNP Track with Tom Carpenter

    CTS207: The New CWNP Track with Tom Carpenter

    Following up CTS 204 (https://www.cleartosend.net/cts-204-cwnp-certifications/) where we talked about the different CWNP certifications, we invited Tom Carpenter (CTO at CWNP) to come and talk about the new CWNP track.

    The new CWNP Track – The Rest of Wireless (IoT)

    In this episode Tom presents the new track, explain who is the target audience and share some behind stories on how they decided to create it.

    Multiple certificates will be part of this new track:

    * CWSA (to be renamed CWISA): Certified Wireless IoT System Administrator. This is the first level of certification and is already available today.* Certification Page: https://www.cwnp.com/certifications/cwsa* Exam Objectives: https://www.cwnp.com/uploads/cwsa-101-objectives-2019.pdf* Study Guide: https://amzn.to/383FshV * CWICP (Certified Wireless IoT Connectivity Professional): covers the PHY of IoT wireless technologies (lower layers of the OSI models)* CWIIP (Certified Wireless IoT Integration Professional): covers the integration of these IoT systems to the enterprise network (higher layers of the OSI Model)* Design certification (not defined yet maybe CWIDP?): it will covers the design aspects

    CWICP & CWIIP should be ready for September 2020. A proctored beta class & exam will take place in August to finalized these new certifications. The JTAs (Job Task Analysis) took place last month.

    Updates on the Wi-Fi Track

    This year, CWNP will be celebrating the 20th anniversary of CWNA. A new version of the certification will be released later on this year.

    CWS, CWT, CWDP and CWAP will be refreshed in 2021 and CWSP will be refreshed in 2022.

    Reminder: the CWNE requirements changed with the introduction of the new track. Instead of needing 2 non-CWNP certifications, you will now need to get CWISA and 1 extra non-CWNP certification.

    Last Chance

    * Last chance to participate to our Audience Survey is still running, please take a minute to give us feedback!* https://cleartosend.net/2019-survey* Last chance to participate to the Wi-Fi Training giveaway (CWNA Lab WorkBook):* Go fill out the form here: https://www.cleartosend.net/what-we-learned-after-200-episodes/

    CTS 206: A look Into 802.11k

    CTS 206: A look Into 802.11k


    * Next Generation CBRS Standard: https://www.businesswire.com/news/home/20200123005555/en/Wireless-Innovation-Forum-Issues-Next-Generation-CBRS-Standard* Client Distribution at CLEUR: https://twitter.com/SNMPguy/status/1222794787398602752?s=20* Ekahau about to launch a new tool: https://twitter.com/ekahau/status/1223368179000455168?s=20* Register for the product launch: https://wifi.ekahau.com/new-tool-to-win-the-war-against-bad-wifi-networks?utm_campaign=2020%20TOF%20Webinars&utm_content=114769185&utm_medium=social&utm_source=twitter&hss_channel=tw-26760583* Eight Wi-Fi Trend expected in 2020 by the WFA: https://www.wi-fi.org/beacon/the-beacon/eight-wi-fi-trends-expected-in-2020* Conference on Port Wireless Solutions: http://www.portcomms2020.com/* CWNP JTA

    802.11k (Radio Resource Measurement)

    802.11k was published in 2008 and added to the IEEE 802.11-2012 standards.

    Various types of measurements are defined that enable 802.11 stations to request measurements from other stations. Information that needs to be measured to optimize the radio network. For example, with 802.11k, stations are able to assess how occupied or idle a frequency channel is. 

    The corresponding request and report mechanisms, and the formats of the frames through which the measurement requests and results are communicated among stations, are defined by the 802.11k amendment.

    Clause 11.11 in the latest 802.11-2016 standards (p. 1709).

    Why did we want to talk about 802.11k

    * It can help client devices to better roam* It has not always been supported on client devices* Clients might lie when they advertise their 802.11k capabilities…

    What is really happening with 802.11k

    * Most of the time APs (or WLC) gather client radio information via specific mechanisms* The client devices can also request some information from the infrastructure (APs & WLC)

    What type of information are we talking about?

    * Neighbor Reports: clients can request a neighbor report and learn valuable information from the infrastructure. The clients will use this information to take better roaming decisions.* Client Statistics: SNR, RSSI, Data rates, frame transmission, retries and errors can be communicated back to the AP & controller.* Channel Statistics: clients might gather noise-floor and channel-load information and send it to the infrastructure.* Transmit Power Control: this can be used to reduced interferences in both frequency bands

    Validate that an SSID supports 802.11k

    * Capture the Beacon Frame* Look for the RM Enabled Capabilities IE* Look for the Neighbor Report Enable bit in the first RM Capabilities section

    Validate that a client supports 802.11k & Neighbor Reports

    * Capture the Association Request (look at the profiler tool from WLAN Pi)* Look for the RM Enabled Capabilities IE* RM Capabilities* Neighbor Report Enable Bit sho...

    CTS 205: 5 Tips For Migrating to the Cisco Catalyst 9800

    CTS 205: 5 Tips For Migrating to the Cisco Catalyst 9800

    Dave Benham was first introduced on the show as a highlight to him and what he does. We interviewed him at a previous Cisco Live. Today we have the joy of having him speak on the show about his tips for migrating to the Cisco Catalyst 9800 wireless controller.

    The Cisco Catalyst 9800 wireless controller is a completely new, from the ground up, IOS XE based wireless controller. The future of Cisco wireless is migrating away from AireOS and into IOS XE.

    Dave Benham has done some deployments and migrations which makes him a perfect person to talk about his migration tips. Before we get to the tips, Dave mentions that this boils down to “tweakability”. Many of the nerd knobs are in different locations as the menu has changed. This is a fresh start to the controller, different from the converged wireless we saw in the past.

    Migration Tips to Cisco Catalyst 9800

    1. Understanding the configuration model

    The IOS XE version is a transition to a new configuration model. No more AP groups, for example. Get ready to use something called site profiles. There’s more flexibility here. It scales better. There is the use of three different tags. We also have the possibility of programmability, both push and pull.

    2. Time to get rid of baggage (Starting Fresh)

    With the migration to the Cisco Catalyst 9800, it is time to start fresh by getting rid of configurations that are no longer being used. Or maybe configuration that won’t transfer at all. We go into this topic in the episode.

    3. AireOS Config Translator

    Built into the C9800, there is a tool to translate your AireOS configuration to IOS XE. You simply upload to the browser. The tool analyzes the configuration and outlines what can and can’t be migrated.

    4. Establishing Mobility

    You will want to establish mobility between the Catalyst 9800 controller and older controllers. Then you can gracefully configure APs to migrate over to the 9800 controllers. There is a special release to establish mobility with the 5508 controller.

    5. Wave 1 APs

    Access points older than Wave 1 not supported on Catalyst 9800. If you have older access points, there may be a good reason to keep the AireOS controllers.

    Links and Resources

    * Dave Benham’s blog* Cisco C9800 deployment guide* Build a Catalyst 9800 lab with an Intel NUC* Viewing network telemetry from the Catalyst 9800 controller* Cisco Embedded Wireless Controller ...

    • 48 min
    CTS 204: CWNP Certifications

    CTS 204: CWNP Certifications

    In this episode, we talk about all the CWNP certifications available today. We provide an overview of each and give some tips on how to study for them. Enjoy 🙂

    The Wi-Fi Track

    CWNP Entry Level Certifications

    * CWS (Certified Wireless Specialist)* https://www.cwnp.com/certifications/cws-100/* Objectives: https://www.cwnp.com/uploads/cws-100-objectives.pdf* Study Guide: https://amzn.to/38kIgqM * CWT (Certified Wireless Technician)* https://www.cwnp.com/certifications/cwt-100/* Objectives: https://www.cwnp.com/uploads/cwt-100-objectives.pdf* Study Guide: https://amzn.to/2tyGzar 

    CNWP Admin Level Certification

    * CWNA (Certified Wireless Network Administrator)* https://www.cwnp.com/certifications/cwna* Objectives: https://www.cwnp.com/uploads/cwna-107-objectives-2017.pdf* Study Guide: https://amzn.to/2udVgQ0 

    CWNP Professionnal Level Certifications

    * CWSP (Certified Wireless Security Professional)* https://www.cwnp.com/certifications/cwsp* Objectives: https://www.cwnp.com/uploads/cwsp_exam_objectives_cwsp-205_2015.pdf* Study Guides: https://amzn.to/2uWTtzb, https://amzn.to/2NTwfRt * CWDP (Certified Wireless Design Professional)* https://www.cwnp.com/certifications/cwdp* Objectives: https://www.cwnp.com/uploads/cwdp-303-objectives-2018.pdf* Study Guides: https://amzn.to/2TBSLSc, https://amzn.to/2NEMwJJ * CWAP (Certified Wireless Analysis Professional)* https://www.cwnp.com/certifications/cwap* Objectives: https://www.cwnp.com/uploads/cwap-403-objectives.pdf* Study Guides: https://amzn.to/2Rt51lB, https://amzn.to/30wQFER 

    CWNE Expert Level Certification

    * CWNE (Certified Wireless Network Expert)* https://www.cwnp.com/certifications/cwne* CWNE Application: https://www.cwnp.com/uploads/cwne-application_001.pdf* Example of CWNE Application (from Rowell): packet6.com/cwne

    CWNP Trainer Certification

    * CWNT (Certified Wireless Network Trainer)* https://www.cwnp.com/certifications/cwnt* CWNT Application: https://www.cwnp.com/uploads/20151202-cwnt_application.pdf

    The New Track – Rest of the Wireless World

    * CWSA (Certified Wireless Solutions Administrator)* a href="https://www.cwnp.

Customer Reviews

JR-John ,


Very technical and informational, helped me a lot! ^_^👍👍

bryan_dearth ,

The Best by Far!

I’ve been listening to this podcast since September 2018, and I have to say it’s the most enjoyable technical podcast I’ve listened to by far. It’s so good in fact, I’ve gone back and listened to almost all of the old episodes as well. From interviews and current news, 802.11 basics to WiFi 6 deep dives, this one covers all the bases. If you are looking for a way to fill you commute and have a passion for Wireless Engineering, do yourself a favor and give this one a try.

Rowell and Francois, please keep the episodes coming!

ortiz3m ,

Great Podcast for those commuting and wanting to become better Engineers

I've been listening to CTS for the last few months and its so refreshing. Sometimes as engineers we can get into a stride and comfortable. This podcast helped me get out and refocused about learning the ins and outs of 80211. Its so important for wireless engineers to be knowledgeable about our environment and Rowell/Francois help with focused episodes. Whether its the new stuff with ofdma, learning what it takes to be CWNE, or fundamentals of proper RF design, you will learn/refresh alot of information that will make you a better 802.11 engineer!

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