Jiri Brejcha - Wi-Fi Technical Solutions Architect

Wi-Fi 7 comes to WLAN Pi M4

With the WLAN Pi team, we have designed and launched a M.2 adapter from A-key to E-key, which allows you to install a certified Wi-Fi 7 adapter Intel BE200 to your current WLAN Pi M4.

Is WLAN Pi selling ‘keys’ now? 😉

What is a ‘key’? It is formed of the notch on the Wi-Fi adapter PCB, and plastic blob separating pins inside the M.2 slot. The idea is to prevent users from plugging incompatible cards to the slot, and avoid any ‘magic smoke events’. Here is more about M.2 and the individual key types if you are interested.

WLAN Pi upgrade kit

Since Intel adapters use E-key and WLAN Pi M4 uses A-key, we needed to build an adapter. Badger Wi-Fi has the upgrade kit in stock. It comprises of the Oscium M.2 A-key to E-key adapter, Intel BE200 Wi-Fi 7 adapter, and 2 little bolts to secure the adapter and the Wi-Fi module.

Here is how the ‘butterfly’ setup looks like. Intel BE200 sits onboard of the A-key to E-key adapter, installed in the M.2 slot.

We are ready to connect existing tri-band antennas, and assemble the unit.

Software support

Make sure to either upgrade Linux packages to their latest versions using sudo apt update && sudo apt upgrade command, or download and flash the latest WLAN Pi software image on your SD card. Release 3.2.0 supports Wi-Fi 7 Intel BE200 adapter out of the box with no effort whatsoever on your part.

Wi-Fi 7 in action

For this demonstration I use a consumer Wi-Fi 7 router TP-Link Deco BE85 BE19000. Simply because it is available, Wi-Fi 7 certified, and it supports 320 MHz channel width – not that one would deploy that in an enterprise environment, but mainly to test the maximum Wi-Fi throughput of the Pi.

A bug in macOS doesn’t allow Macs to correctly recognise Wi-Fi 7 networks. Instead of Wi-Fi 7 320 MHz wide network, my MacBook reports Wi-Fi 6 and 160 MHz wide channel. So, we will use another WLAN Pi and its Wi-Fi radio as a Remote Sensor in WiFi Explorer Pro – you need the Pro version to do this.

Nice, Wi-Fi 7 AP!

Connecting the WLAN Pi as a Wi-Fi 7 client only takes few lines of wpa_supplicant config.

sudo nano /etc/wpa_supplicant/wpa_supplicant.conf

And we have successfully connected the WLAN Pi as a Wi-Fi 7 client to the AP using this command.

sudo wpa_supplicant -c /etc/wpa_supplicant/wpa_supplicant.conf -i wlan0

Run this command to make sure the WLAN Pi requests an IP address from DHCP server running on the router:

sudo dhclient -i wlan0 -v

What channel are we using? 320 MHz channel width? Indeed.

Before you ask, distance between the Pi and the router is sub 1 meter. What is the Wi-Fi data rate? We are using Wi-Fi 7 (EHT), 2 spatial streams, MCS 12 and 4096-QAM and short guard interval of 0.8 µs.

We can refer to Francois Verges’ MCS index tool to check how we are doing. Yes, I have tried, but I have only been able to achieve MCS 13 extremely rarely.

How far from the AP can we maintain 4096-QAM?

I hardly ever achieved MCS 13. To maintain MCS 12, I had to stay within about 1.5 meter distance from the router. I got best results with antennas position in this ‘V’ pattern.

My noise floor was -96 dBm and RSSI typically between -29 and -39 dBm.

With a different client device designed for Wi-Fi 7 from the ground up (with professional quality antennas and placement), I would hope for slightly longer MCS 12 and MCS 13 range.

It’s throughput test time

It’s time to run an iperf3 test and see how much traffic we can actually push over the air and also how much the WLAN Pi M4 can handle. Here is our test setup. I recommend the OWC 10 GbE Thunderbolt adapter (it uses Thunderbolt protocol, not USB) connected via USB-C to your Mac.

With the help of Oscium WiPry Clarity 6 GHz spectrum analyser connected to another WLAN Pi, we can monitor the life spectrum and see how much red the iperf3 test introduces. We are able to achieve download TCP speed of 2.27 Gbps and upload speed of 1.74 Gbps.

I used iperf3 -c 192.168.68.51 -P32 -R to test download speed, and iperf3 -c 192.168.68.51 -P32 for upload. Number of parallel streams set to 32 provided the best performance.

Summary

Wi-Fi 7 works well on the WLAN Pi M4. In fact, it works better than Wi-Fi 7 on Windows 11. We have covered Intel BE200 on Windows 11 in this blog posts.

I was expecting 2.5 Gbps-ish throughput, which we have got quite close to. During the test, CPU of the WLAN Pi was running around 80 % utilisation, and interrupts were reaching 100 %. So, hardware of the WLAN Pi itself posed a bottleneck.

mpstat 1 300 -P ALL

Orientation of the antennas mattered more than I expected to. Best position was a ‘V’ shape with antennas positioned away from the board. With AUX antenna placed 90 degrees relative to the Main antenna, data rates and throughput dropped. Perhaps there is RF noise from the board itself coming into play.

Apple iOS Shortcut: Install Wi-Fi diagnostics profile to your iPhone the easy way

Apple developed a diagnostics profile that allows you to monitor and troubleshoot Wi-Fi connectivity. Unfortunately, it is only available for 7 days after installation. After that, it get automatically removed. If you are a Wi-Fi professional, that means that you need to reinstall it every few days. Yes, it always disables when you are on site and need it the most :)

Manual installation of the profile – the hard way

Normally, I would google something along the lines of “Apple Wi-Fi diagnostics profile”, eventually I find the right link, log in, search for the iOS Wi-Fi profile on the Apple Developer website, download the profile, go to Settings > General > Profiles section, and I install it from there.

Wi-Fi diagnostics profile for iOS devices

What if there was a little tool that did most of the above for you?

The easy way

I put together a quick “Wi-Fi Profile” Apple Shortcut that removes some of these steps. Install the shortcut on your phone and it will guide you through the diagnostics profile installation every time you need it. It downloads the profile to your iPhone, lets you approve the installation and voilà, you open Wi-Fi settings and get RSSI measurements, channel details, BSSID and other useful info.

How to add the Shortcut to your phone

Download the latest version from my GitHub and follow the video instructions. Save it your home screen and execute it whenever you want to reenable Wi-Fi diagnostics.

See the shortcut in action

More shortcuts, anyone?

I wrote few other Shortcuts. Perhaps you are connected to a someone’s guest network, and would like to see who their access point vendor is? Your iPhone can tell you.

Or you use 2 iPhones and want to get a reminder when your secondary/test phone’s battery drops below 10%?

Convert Cisco Catalyst Wireless access point to Meraki cloud-managed mode

We have already converted a Cisco Meraki access point to Catalyst/DNA mode the other week.

Access point conversion from Catalyst/DNA mode (managed by Catalyst 9800 controller) to Meraki mode allows you to add a Catalyst Wireless AP to Cisco Meraki Dashboard, and fully monitor, and fully manage it from there.

Order the AP in the right mode

Order your access points in the right mode out of the box, and don’t worry about conversion. That’s the “-MR” SKU for cloud-management/SaaS model. If you wish to manage the APs by a Catalyst 9800 controller, simply find the right access point SKU and regulatory domain based on your coutry using this tool and reach out to your favourite Cisco Partner or distributor for a quote.

What do we need?

Catalyst Wireless CW9162I, CW9164I, CW9166I, CW9166D1, or CW9163E access point joined to a Catalyst 9800 series controller (hardware appliance, cloud instance, or virtual machine)
Cisco Meraki MR access point license

Let’s start the conversion

1. Make sure the access points you want to convert have successfully joined the Catalyst 9800 controller. Head over to Configuration > Wireless > Migrate to Meraki Management Mode.

2. Select one or more APs you wish to convert and click the Migrate to Meraki Management Mode button.

3. Wait for validation to complete. Click Next.

4. Tick Agree and continue and click Yes.

Take a deep breath and kick-start the process

5. Conversion has now finished. Note that each AP has a Cisco Serial Number and Meraki Serial Number. Copy the Meraki Serial Number.

6. While you are doing that, the AP rebooted and started the Meraki image.

AP has left the controller and is about to establish connectivity to Dashboard after reboot

During the boot process, the AP logs a message about the mode change.

Reset reason – AP converted to Meraki mode

And you will no longer have access to its Console port. If you connect a console cable, <Meraki> output will appear with no option to type any commands.

7. Copy the Meraki Serial Number and log in to Cisco Meraki Dashboard. Open Organization > Configure > Inventory. Click Add devices, and paste the Meraki Serial Number of the AP.

Add the AP by entering its Meraki Serial Number

8. From now on, the AP now behaves like any other Meraki cloud-managed access point. All monitoring and management features of the Dashboards are available. If you ever change your mind, and wish to convert it back to Catalyst/DNA mode, here is my step-by-step guide.

Useful WiFi Explorer Pro filters for finding rogue APs and APs with low minimum mandatory data rate

If you have not used WiFi Explorer before, get yourself a copy of the Pro version here. It is absolutely worth it and extremely useful tool if you have anything to do with Wi-Fi.

The Pro version (the Lite doesn’t) supports Filters. They allow you to filter scan results and get exactly the scan results you are interested in.

Find rogue access points

Let’s say you want to find APs that use other SSIDs than yours. This filter does just that. It shows all SSIDs other than CiscoLive or CiscoLive-WPA3. Simply paste this string into the Filters text field in the top right-hand corner.

dot11.net.ssid !~ "CiscoLive" AND dot11.net.ssid !~ "CiscoLive-WPA3"

Find APs using low minimum mandatory data rate

Other times you might want to look for access points that have minimum mandatory data rate configured to low – by mistake or by choice. In this example, I am interested in APs broadcasting these 2 SSIDs and using minimum mandatory rate of 6 or lower.

dot11.net.min_basic_rate <= 6 AND dot11.net.ssid ~~ "CiscoLive" OR dot11.net.ssid ~~ "CiscoLive-WPA3"

Download the cheat sheet

We have only scratched the surface. You can do so much more with filters.

Intuitibits, the makers of WiFi Explorer, published a great one-pager documenting the syntax. Get yourself a copy.

Convert Cisco Meraki MR access point to Catalyst DNA mode

Same hardware, your choice of management

The latest generation of Wi-Fi 6E Catalyst Wireless access points (CW9162, CW9164, CW9166 series) gives you the option to either cloud-manage them using Cisco Meraki Dashboard, or manage the APs by Cisco Catalyst 9800 series Wireless LAN Controller (WLC).

They are the exact same hardware and they ship pre-loaded with the Catalyst/DNA and Meraki software image. Depending on the mode setting, they either boot one image or the other.

What do we need

Catalyst Wireless CW9162I, CW9164I, CW9166I, CW9166D1, CW9163E access point in Meraki mode
Cisco Meraki MR access point license to perform the conversion
Cisco DNA Essentials or DNA Advantage access point license if you want to use join and manage the AP by a Catalyst 9800 controller

Choose AP mode before ordering

You will have the best experience when you order your access points in the right mode.

Order a DNA persona AP and it will auto-discover your Catalyst 9800 controller using one of the supported methods. In the UK, I can order the “-ROW” AP and manage it by Catalyst 9800, and optionally add Catalyst Center (previously known as DNA Center) to get analytics, assurance and other great features. Find the right access point SKU and regulatory domain based on your coutry using this tool.

If you prefer, order the Meraki mode access point, connect it to the internet, and claim it in the Dashboard. Meraki APs use a single “-MR” SKU globally.

Conversion from MR to Catalyst/DNA mode

If you ordered a Meraki access point and your requirements have changed, you can convert the AP to DNA mode.

1. Make sure you have an active Meraki MR license. Why? We need the license to connect the AP to Dashboard, and to open a conversion request with Meraki technical support team.

2. Provide power and internet connectivity to the access point.

3. Log in to Dashboard. Navigate to Organization > Configure > Inventory and add the access point using its Meraki S/N.

Enter the Meraki S/N from the product label

4. Add your MR license to Dashboard under Organization > Configure > License Info.

5. Wait for the AP to connect to Dashboard and change its LED to solid green or solid blue. Perfect, the AP is now online.

6. Complete this checklist first. Disable Meshing feature and make sure your Catalyst 9800 is ready for the AP to connect after conversion has completed.

7. Open a new support case by clicking the (?) question mark in the top right hand corner > Cases > New Case.

8. Include all these details to speed up the conversion process. Find your Customer Number by clicking the person icon in the top right hand corner. To get your Daily Support Code, click the same person icon, then open My profile.

Hi,

Please convert my CW*****-MR AP with Meraki SN ****-****-**** to DNA mode. I do have an existing DNA license. I disabled Meshing in the Dashboard.

I have completed this checklist:
https://documentation.meraki.com/MR/Other_Topics/916X_Management_Mode_Checklist_and_Troubleshooting

I am aware that the AP will not join Dashboard after the conversion, unless I convert it back to MR mode.

Please go ahead and start the mode change immediately.

My customer number: ****-****
My support passcode for today: ****

Have a great day!

9. If this conversion is urgent, call into Meraki support. No, don’t e-mail the support team, call them. Have the case number by hand. Find the best phone number here.

10. After the support engineer starts the conversion, your AP will reboot. It is now in the Catalyst mode. You can verify that by keeping an eye on the Console port output during its boot. Just to remind you (and myself): The new Console port baud rate is 115200 from 17.12.1 release onwards.

Autoboot in 5 seconds
Catalyst Mode Selected

11. The AP should now follow the standard Catalyst LED pattern. It is ready to be managed by a Catalyst 9800 series controller – be it a hardware appliance, virtual machine, or public cloud instance.

12. Our DHCP server assigned an IP address to the AP, which has automatically discovered and joined the WLC located in the same IP subnet.

Followed by automatic software image upgrade

The AP has joined the WLC and is ready for use

To enable SSH and Console access, create a username, password and enable password in the Catalyst 9800 controller’s AP Join Profile > Management > User section. SSH protocol is disabled by default. You can enable it in the AP Join Profile.

You have full Console access and control over the AP

Will faster micro SD card make my WLAN Pi M4 boot faster?

No, it will not, unless you make some bad choices. But, faster card will make your life easier and significantly speed up the image flashing process.

Tests performed

Flash and verify WLAN Pi 3.1.4 software image to the micro SD card using built-in card reader of MacBook Pro M2 and Balena Etcher app

Boot WLAN Pi M4 from the micro SD card. Measure how long it takes to boot from plugging the Ethernet cable in (and PoE power provided) to WLAN Pi home screen shown on the display

Results

Sandisk High Endurance 32 GB U3 card is the default provided with WLAN Pi M4 by default. The U3 standard reall y makes a huge difference when it comes to writing to the card and that’s why it is our go to option.

From practical perspective, different size or even slightly slower card won’t really make your Pi boot any faster. If you make some bad choices and reuse an older class 6 card, you will spend extra 11 seconds of your life waiting for the WLAN Pi to boot every single time.

	Flash WLAN Pi image	Effective speed	Boot WLAN Pi M4
Sandisk HE 32 GB U3	1 min 59 seconds	64 MB/s	28 seconds
Sandisk HE 256 GB U3	1 min 53 seconds	68 MB/s	28 seconds
Sandisk Ultra 32 GB U1	3 mins 54 seconds	24 MB/s	28 seconds
Samsung 8 GB Class 6	11 mins 29 seconds	8 MB/s	39 seconds
Compute Module 4 with built-in eMMC storage	Didn’t test	6.5 MB/s	27 seconds

Recommendation

Invest in a U3 or better card and benefit from fast write speeds. There is very little premium to pay. In future, you can reuse a fast card in other device like a dash cam, Raspberry Pi 5 workstation, or video camera.

Kingston has a great blog post about SD card standards.

Apple iOS Shortcut: Remind me to charge my secondary iPhone

Let me give you one more reason why you should explore the Shortcuts framework on your iOS or macOS device.

Remind me to charge my test phone

I mainly use my primary iPhone, but for testing I use an older iPhone running iOS Beta. Up until now, I struggled to keep the test phone charged. Typically I would pull it out of the bag and … you know the rest of this story, right?

I put together this quick but very useful shortcut. Whenever charge level drops below 10 %, the secondary phone will automatically send me an iMessage with a reminder. That’s it. Simple. Useful.

Recharge reminder automatically sent to me via iMessage from the secondary device

How does it work

Simply create a new Shortcut on the secondary iOS device, using the Shortcuts app. Select Send Message action and enter your iMessage details.

Now, in the Automation section, configure the trigger that executes this action. Set it to run whenever battery level drops below 10 %.

Then hit Done.

Micro SD card adapter that travels inside your MacBook’s SD card reader

I flash Micro SD cards few times a day (hello WLAN Pi team 😉), and I thought it might be a good idea to always have an SD card to Micro SD card adapter on me. The easiest way to do that is to insert one in your MacBook built-in SD card reader slot. But which one do you buy?

Supplied adapter

There is nothing wrong with this SanDisk adapter. But it sticks out of your laptop. You can’t leave it inserted in the Mac while travelling. And also, the Micro SD card might slip out of the adapter.

White OEM Micro SD to SD card adapter

To my surprise, this £2.60 adapter worked great… for a couple of weeks 😅 Until it disintegrated. It was designed for previous generations of MacBooks and it is not flush with the body of M1 MacBook, but it is still smaller than the full-size adapter.

You can shave off the grey plastic part, and make it even smaller. The white part allows you to easily remove and reinsert the adapter. No nails required.

The Micro SD card goes in the adapter from the side, so it won’t eject in your backpack or laptop bag.

It flashes cards at the exact same speed 61.8 MB/s as the premium £30 BaseQi. And it is easy to remove from the MacBook card reader slot.

BaseQi 420A

This adapter is primarily designed for those who want to expand storage capacity of their MacBook. And it does that really well. It fits perfectly inside SD card reader slot of 14″ M1 2021 MacBook. The problem is that it works ‘too well’. Once you insert the Micro SD card to it, it is very hard to remove the Micro SD card. Now, when you insert it into MacBook SD card reader, it is designed to stay there and again it does that ‘really well’.

Removal of BaseQi from the MacBook card reader takes 2 fingers and 2 nails. Yes, it takes significant effort.

Would I recommend it to someone who wants to use it to flash Micro SD card few times a day? No. It takes a huge effort.

Afterplug Ultra Slim Stick On SD and MicroSD Card Holder with Reusable Adhesive

Problem solved! This stick on card holder did the trick. I can reuse all my SanDisk SD card to micro SD card adapters. And I can carry a handful of them, label them and store the micro SD cards inside the adapters.