CTS 150: Wi-Fi Design Day, NAC, Troubleshooting, C9800, and More

Stephen Cooper flies from Australia to San Jose to record in-person for Clear To Send. But really he was in town for work and made time to meet with me, Rowell, to talk about different topics in wireless.

Interview with Stephen Cooper

We met at the Westin hotel which happened to be the quietest place downtown due to a winter holiday event occurring.

He’s a Technical Solutions Architect for Cisco residing in Australia. Previously was the Ekahau SE for Asia Pacific working out of Australia. And before that he was at Dimension Data.

It’s challenging to find wireless guys who understand wireless and network access control such as Cisco ISE or Aruba ClearPass. At Dimension Data Stephen had to work on these types of projects. Network access control usually falls with the security team and the wireless guys don’t have much insight into how it’s deployed.

Troubleshooting is critical for wireless professionals. Understanding how the network should be working helps identifies root causes faster.

While at Ekahau, Stephen was very remote from the rest of the team. He met with a lot of customers where shifting their minds towards thinking about design first and understanding fundamentals. A vendor default is not vendor recommendation. And a challenge Stephen noticed at Ekahau is customers may not necessarily know that distinction.

When it comes to design, we often see that device types are forgotten and not considered into the design process. But the wireless community has been very good at bringing device types and their characteristics into light.

Moving to Cisco, Stephen has been able to work with clients on wireless designs, helping with migration strategies between controllers, helping customers understand how to get onto locations services network or VoIP ready network. He’s more focused on wireless and Cisco DNA – future architecture.

With Cisco’s next generation wireless architecture and intent-based network, Stephen thinks you have more flexibility with how you can deploy new controllers, but there’s still life in the AireOS controllers. There’s a large legacy install but they can still do telemetry you can use in DNA Assurance. You may not get the same level as detail compared to the C9800s.

Wi-Fi Design Day was born out of Ekahau and was started in the UK. It was meant to educate people but have it a community driven event. The first event was a huge success in London and when it was announced in Australia it was also popular. The event is unique where it’s vendor neutral with experts from multiple vendors talking about Wi-Fi as well as end users talking about their use cases. This event is much smaller and intimate compared to larger conferences.

Links & Resources

Twitter: Stephen__Cooper

Wi-Fi Troubleshooting and Optimization

#CiscoChampion Radio is a podcast series by technologists for technologists. In this episode, Cisco Champions Rowell Dionicio and Robert Boardman discuss Cisco WiFi Troubleshooting and Optimization with Jerome Henry.

Jerome Henry is a Principal Engineer, Technical Marketing in the Wi-Fi Business Unit. He has extensive experience in troubleshooting wireless networks. In this Cisco Champion Radio episode, we talk Jerome about tools for troubleshooting wifi, packet analysis and MIMO considerations, using Excel to troubleshoot (yes Excel!), access points coverage, most common issues, and Jerome’s process for optimizing a wireless network.

Rowell and Robert host a video channel together called Wi-Fi of Everything. Be sure to check it out and subscribe!

You can catch this episode on Sound Cloud and listen to the other Cisco Champion Radio episodes as well.

CTS 120: 6 Warehouse Troubleshooting Wi-Fi Tips

Troubleshooting Wi-Fi in a warehouse environment can get complex. We outline 6 tips to help you out.


6 Warehouse Wi-Fi Troubleshooting Tips

Warehouse environments are tricky. They’re complex. Many factors can limit how well Wi-Fi works. There are tall racks which go as high as 30 feet or more. Depending on what kind of material is stored in those racks it can change the characteristics of the Wi-Fi signal.

In this episode, we talk about 6 Wi-Fi troubleshooting tips you should know when working in a warehouse:

Client Care

Wi-Fi clients need more love. They aren’t handled as careful as they should be in these harsh environments. Many devices are rugged at all and could affect Wi-Fi connectivity. Give these devices a physical look over for any damage. Devices also have a longer life cycle in warehouses. You’re not always working with the latest and greatest technology.

Client Configurations

Keep aware of the feature sets of the client devices. Each type of device will have different roaming thresholds or triggers in their configuration, if any. Many devices in warehouses are sensitive with the real-time application that’s being used. One thing to always look out for are the firmware versions installed.

Directional antennas

Because of the high ceilings and tall racks, directional antennas are highly recommended. With omnidirectional antennas, it may not penetrate the materials in the rack. This creates connectivity issues for scanner guns and any other type of devices used in between racks. Find out what type of material is sitting on those shelves to get an idea of attenuation. Ensure antennas are mounted properly and not on top of a rack.

Operating a Skyjack

Someone has to get up to the ceiling and install an access point or antenna. The important part here is to be aware of any licensing you may need to acquire or training you need to attend before operating a skyjack. Safety is very important in a warehouse, for yourself and others. Don’t forget any other equipment you may need such as a hard hat, safety vest, safety glasses, harness, steel toe boots, etc.

Hardware failures

Harsh environments have a negative affect on equipment. The environments, indoor or outdoor, can lower the life of a device. Be sure to do a physical check of hardware. You may seen an antenna hanging from a device because it was knocked off while on the move. There may be some failed equipment because it was in a freezer and didn’t hold up to the freezing temperatures, etc.

Retry Rate

Legacy 802.11b/g clients do not hold up well in warehouse environments relying on Wi-Fi. They don’t handle multi-path very well. This is why we recommend using updated client devices but we know it’s not always an option for a company to spend lots of money on updating aging equipment. We’ve seen up to 50% retry rates in warehouses. But with newer clients it decreases since they can handle multi-path. You may need to change your APs and/or antennas to tune for the client device in these complex environments.

Link and Resources

CTS 070: Wi-Fi Troubleshooting with Debookee

We welcome Thomas Baudelet from France. Together, we talk about network and Wi-Fi troubleshooting in general and we go over the Mac OS application called Debookee that Thomas created which could be use to troubleshoot a Wi-Fi network.

Thomas Baudelet works as an independent Network Engineer and specializes in troubleshooting. He has been involved in the Wireshark community and he created a network analyzer application for MacOS called Debookee. Feel free to follow him on Twitter @debookee.


  • Presentation of the Debookee tool, Thomas gave us a little bit of history on how he decided to create the tool
  • Presentation of the different modules (including the Wi-Fi Monitoring module)
  • Presentation of what is coming next (New SSL decrypt module)
  • Thomas explains how he studied Wi-Fi in order to be able to create a tool that would be used by WLAN professionals
  • Troubleshoot methodologies
  • What tools does Thomas uses on the field

Screenshots of Debokee

Displaying channel statistics

A look at channel statistics


Devices using Wi-Fi

Scanning devices using Wi-Fi


Here are some useful links related to this week episode:

Upcoming Episode on Wi-Fi Issue

Want to participiate in a future episode? Here is the link to the Wi-Fi issues submission form for one of our upcoming episode:

Wi-Fi Issue Submission

This Week in Wireless

  • WikiLeaks says it has obtained trove of CIA hacking tools
    • WikiLeaks has gained access to CIA hacking arsenal.
    • The document shows that the CIA turn devices into collection devices (iPhones, iPad, Smart TV…).
  • Additional unlicensed spectrum needed to deliver future Wi-Fi® connectivity
    • The “Wi-Fi Alliance® commissioned the Wi-Fi Spectrum Needs Study to assess whether available spectrum resources will be sufficient to support Wi-Fi connectivity in the future. The study indicates that by 2020, Wi-Fi networks around the world will need access to significantly more mid-band spectrum than is currently available in the 5 GHz range to satisfy expected growth in Wi-Fi data traffic.”
    • Download the study:
  • New CWNEs!!
    • Tom Van Driessche from Belgium is now CWNE #219
    • Aren Gates, who I believe works for Aerohive, is now CWNE #220
  • CWTS Discontinued (Certified Wireless Technology Specialist)
    • It has been announced by the CWNP this week, the CWTS will retire at the end of the year.
    • This certification is a lifetime certification and you can still write the exam if you would like before the end of the year. CWNP is offering a $50 discount and free access to eLearning and practice tests material.
    • Twitter announcement
    • State of the CWNP program
  • PacketPushers
    • We’ve been interviewed by the PacketPushers podcast team about 2 months ago and they released our interview last week in an episode entitled “Wireless networking and where it’s going”. Weekly show episode 331.
  • Carrier Wave
    • As always, the great Carrier Wave from Omar Vazquez to keep in touch with all the amazing Wi-Fi blog articles being published.