Some of you have asked about the lanyard I use with my WLAN Pi R4. So here is how to make yours.
What does it do?
It allows you to ‘wear’ the R4 while keeping your hands free. You can perform 2.4 GHz, 5 GHz or 6 GHz scanning, spectrum analysis, or packet capture from your Mac.
WLAN Pi R4 with 6 GHz Wi-Fi adapter and 6 GHz spectrum analyser as a remote sensor to WiFi Explorer ProWearable WLAN Pi R4
What parts do I need?
My goal is to use a standard conference lanyard. Use your favourite one or order a custom one with your name or company name. In the UK, I use greencotton on eBay and they have been great.
WLAN Pi R4 lanyard, D rings and bolts
After many iterations, I discovered that these D ring picture holders work best. They are made of metal, of perfect size and readily available. So there is no reason to overengineer this or reinvent the wheel.
Finally, we need two M2.5 x 5 mm bolts to attach the D rings to the bottom of the Waveshare heatsink.
D rings attached to WLAN Pi R4Lanyard attached to WLAN Pi R4
Since Apple hasn’t published any documentation that would cover this subject, I configured a tri-band SSID on Catalyst 9136 AP. The SSID name is the same for all 2.4 GHz, 5 GHz and 6 GHz bands. Now, what band does iPad prefer?
Setup
Wi-Fi 6E iPad Pro 11-inch (4th generation) running iPadOS 16.1
Catalyst 9136 Wi-Fi 6E AP
C9800-CL cloud controller running 17.9.2
Max transmit power and 80 MHz wide 5 GHz channel
All 3 bands are enabled with manual Power Level 1 (PL1), which forces the AP to use highest permitted Transmit Power.
In this case, the 6 GHz SSID had the strongest absolute signal strength (RSSI) of the 3 bands.
2.4 GHz enabled, PL1
5 GHz channel 36, 80 MHz wide, PL1
6 GHz channel 5, 80 MHz wide, PL1
The iPad prefers the 5 GHz band and joins using this band.
Reduce transmit power on 5 GHz radio
Let’s use the exact same configuration as above and reduce 5 GHz radio’s transmit power to the lowest, Power Level 8 (PL8). Will that make it prefer 6 GHz?
2.4 GHz enabled, PL1 (RSSI on the iPad -31 dBm)
5 GHz channel 36, 80 MHz wide, PL8 (RSSI on the iPad -55 dBm)
6 GHz channel 5, 80 MHz wide, PL1 – strongest absolute RSSI (RSSI on the iPad -30 dBm)
Yes! The iPad Pro prefers 6 GHz every single time. As you can see, the 6 GHz RSSI is 25 dB stronger than the 5 GHz one, which is why (as far as I can tell).
Narrower 5 GHz channel
We are using the the same configuration as in our very first scenario, but 40 MHz we will reduce 5 GHz channel width to 40 MHz.
2.4 GHz enabled, PL1
5 GHz channel 36, 40 MHz wide, PL1
6 GHz channel 5, 80 MHz wide, PL1
Using narrower 5 GHz channel makes the iPad connect using 6 GHz instead.
Disable 5 GHz radio
This time we disable 5 GHz radio and see if 2.4 GHz or 6 GHz wins. I have high hopes for 6 GHz, you?
Now, let forcefully shut the 6 GHz radio on the AP. iPad moves to its only available option, the 2.4 GHz radio and happily lives there. We now reenable the 6 GHz radio. The iPad doesn’t automatically jump back to 6 GHz, although 6 GHz has stronger RSSI. When we disabled iPad’s Wi-Fi radio, and reenable, it connected on 6 GHz.
Make 2.4 GHz stronger than 6 GHz and disable 5 GHz
Can we make 2.4 GHz appealing enough to the iPad so that it would prefer it over 6 GHz? Let’s disable 5 GHz radio, keep max transmit power on 2.4 GHz, and reduce 6 GHz transmit power to the lowest Power Level 8 (PL8).
2.4 GHz enabled, PL1
5 GHz disabled
6 GHz channel 5, 80 MHz wide, PL8
The 6 GHz RSSI (-45 dBm) is now weaker than the 2.4 GHz RSSI (-33 dBm) by 12 dB. Is it good enough reason for the iPad to prefer 2.4 GHz?
Not really. It connected on 6 GHz 2 times out of 3. Once it connected on 2.4 GHz.
Summary
When 80 MHz wide 5 GHz channel is used, the iPad prefers 5 GHz. If 5 GHz drops below a certain threshold, and is much weaker than 6 GHz, it then prefers 6 GHz.
It prefers 6 GHz over 40 MHz wide 5 GHz channel.
It doesn’t use 2.4 GHz unless it has no other option.
Please take these tests with a pinch of salt. Ideally I would repeat each of them 10 or so times. Time is of the essence and I only repeated each test 3 times.
Same as in the iPad test, we are going to test how well the 6 GHz SSID discovery works and learn a thing or two about Pixel 6.
Discovery with 6 GHz only SSID
Let’s configure Catalyst 9136 AP running 17.9.2 release with 6 GHz only SSID. This is the only SSID this AP broadcasts. There are no 2.4 GHz or 5 GHz SSIDs enabled. They only way for the AP to discovery the SSID is to scan the 6 GHz channels. We refer to these methods as in-band discovery.
Reduced Neighbour Report (RNR), which normally uses 2.4 GHz or 5 GHz beacons to tell the client about 6 GHz SSIDs, is not available to us, because we don’t have any 2.4 GHz or 5 GHz SSIDs on the air.
We are using 80 MHz wide 6 GHz channel 7, which uses primary channel 5. That is a Preferred Scanning Channel (PSC), which means that clients should scan it. Our 6 GHz only SSID is called Cisco 6.
6 GHz only SSID is the only one enabledChannel Number allows us to configure the Primary channel
Unfortunately, our Pixel 6 won’t discover the SSID.
No signs of 6 GHz
But, if we move the AP to channel 23, which uses primary non-Preferred Scanning Channel channel 17, the smartphone discovers Cisco 6 instantly! How bizarre.
6 GHz SSID discovered
I went through the “test all lower 6 GHz channels” exercise and here is the outcome.
When I use these primary channels, Pixel 6 will happily discover the 6 GHz only Cisco 6 SSID: 13, 17, 21, 25, 29, 33, 53, 57, 61, 65, 69, 73, 89
Using these primary channels will make the smartphone not discover it: 1, 5, 9, 37, 41, 45, 49, 77, 81, 85, 93
Here is graphical representation of this. Credits to Keith Parsons and the WLAN Pros team for creating this chart.
For the record, on some channels it took little longer to connect.
Changing channel width to 20 MHz, 40 MHz, or 160 MHz did not help with SSID discovery. Which makes me think that Pixel 6 does not scan these channels at all.
Here is what is happening on the 6 GHz channel when we only enable 6 GHz SSID (with no 2.4 GHz and 5 GHz) on the AP. The AP automatically starts broadcasting FILS frames to help the client discover the 6 GHz SSIDs.
6 GHz only SSID plus 5 GHz only SSID and out-of-band discovery
Now the torture is over and we are calling 5 GHz for help. We will use out-of-band discovery.
5 GHz only and 6 GHz only SSIDs enabled
By keeping the 6 GHz only SSID enabled, and adding 5 GHz only SSID, we will allow the AP to tell the Pixel 6 about 6 GHz SSIDs in its 5 GHz beacons. There is a Reduced Neighbour Report (RNR) Information Element (IE) included in the 5 GHz (and 2.4 GHz beacons when we use 2.4 GHz), which is the preferred way of discovering 6 GHz.
RNR IE in 5 GHz beacon informing the client about 6 GHz AP
The client failed discovery on primary channel 5. Let’s use that this time and see if RNR fixes discovery for good.
Yes! We see both SSIDs instantly. By enabling 5 GHz (or 2.4 GHz) SSID with the same or different SSID name, Pixel 6 can now discover all channels. This is the preferred way of discovering 6 GHz networks.
RNR IE in 5 GHz beacons helps the client discover 6 GHz SSIDs
Note: When RNR is active, the AP will automatically stop sending FILS frames and there is no way (and no reason, because RNR is a much better method) to force-enable FILS.
Summary
With 6 GHz only SSID (without 2.4 GHz and 5 GHz), Pixel 6 will only discover it using in-band methods if we use primary channels 13, 17, 21, 25, 29, 33, 53, 57, 61, 65, 69, 73, 89.
After enabling 5 GHz (or 2.4 GHz) SSID, Pixel 6 discovers the 6 GHz SSID by looking into the RNR IE in the 5 GHz (or 2.4 GHz) beacon frames.
I am very happy with how well the 6 GHz discovery using 2.4 GHz or 5 GHz beacons works. It definitely is production ready. The test with only one 6 GHz only SSID on the AP is more of a corner case. Most customers I work with, if not all, will also deploy 5 GHz alongside 6 GHz, so there is absolutely nothing to worry about.
Packet capture or it didn’t happen 😉
Download 2.4 GHz an 5 GHz RNR, 6 GHz FILS, and 6 GHz unsolicited probe response packet captures from here.
Download WLAN Pi Profiler report and packet capture of 5 GHz association request, and also 6 GHz association request. We can see client’s capabilities in these frames.
Bonus: Add second 6 GHz SSID and see how it impacts RNR
Same setup as before, we have 5 GHz only SSID Cisco 5 and 6 GHz only SSID Cisco 6, but this time we add an extra 6 GHz only SSID Cisco 66.
Both 6 GHz SSIDs are now advertised to clients using the RNR IE in 5 GHz beacons.
Both 6 GHz SSIDs advertised using RNR IE in 5 GHz beacons
This question comes up and every now and then. So, let’s put it to bed.
If you have a ceiling mounted internal antenna AP (with built-in antennas), or external antenna AP with dipole antennas (AIR-ANT2524D), or with short dipole antennas (AIR-ANT2535SD), here are the correct Azimuth and Elevation angle settings.
This is how 0° Azimuth and 0° Elevation look like. Plus “squished doughnut” as a bonus to illustrate the coverage pattern 🍩
Azimuth angle does not matter in this case (it does for directional antennas), because these antennas have the same pattern regardless of how you rotate them clockwise or counterclockwise. Simply use the default value of 0°.
Elevation angle is 0° for this orientation.
Cisco DNA Center Azimuth and Elevation configuration
Let’s take this “Back to the basics” question and test things out.
So, we have this 20 MHz capable Windows 11 Wi-Fi client and we want to see what happens when it attempts to join an SSID that uses 80 MHz wide channel. Will it associate? Will it fail?
Here is my client with Intel AX201 adapter forced to only support 20 MHz wide 5 GHz channel.
My AP uses 80 MHz channel width.
Let’s verify the settings from a Mac. Yes, the AP broadcasts 80 MHz wide “lab5” SSID with primary channel 36.
Finally, what happens if the client device is only capable of 20 MHz channel width? As you can see, it will happily join using Primary channel 36.
More capable client devices that support 80 MHz channel width will benefit from the 4 bonded channels and use the 80 MHz channel in its entirety.
My Catalyst 9800-CL controller is hosted on a cloud, so I don’t need any hardware for that. Finally, my Catalyst 9136 Wi-Fi 6E AP is powered by a Catalyst 3560CX 10 Gigabit Ethernet multigigabit switch.
6 GHz 2×2 MIMO setup powered by PoE+
Catalyst 9136 is Cisco’s premium AP with all the bells and whistles including hexa-radio architecture and built-in environmental sensors for smart building use cases. It requires an 802.3bt/UPOE power source to enable 6 GHz radio in full performance 4×4 MIMO mode. The switch I use supports 802.3at/PoE+, which is great, but 6 GHz radio downshifts to 2×2. And that’s where an 802.3bt power injector comes to the rescue.
Since the Cisco injector isn’t widely available yet, I decided to test this Zyxel one. It provides 802.3bt power and allows the AP to run in full power and full 4×4 6 GHz radio mode with no compromise.
Do I like power injectors in production?
Absolutely not! Ideally you should design for 802.3bt/UPOE switches to power all your new APs via PoE.
It allows you to:
easily, centrally and remotely monitor how much power the APs use
enable/disable power on a port to bounce an AP
leverage redundant Platinum-rated power supplies for the AC to DC power conversion
manage the solution with ease – just think how difficult it is to manage more than 1 power injector, the number of AC power sockets, and what happens when someone disconnects the injector?
I still use C3650 UPOE mGig switch in my lab. Catalysts 9300 and 9400 the best choice these days.UPOE and mGig capable C3650 providing full power to the AP
Final look
Carrying a full-size switch is not really an option for me, because small form factor is my main goal. So a power injector works best for me. But if I could I would love to use a compact 802.3bt switch.
Are you wondering if the PoE splitter connected to my iperf3 server (the little black box with 3 Ethernet interfaces) actually negotiated 2.5 Gbps Full duplex with the switch? Yes, it did. But keep in mind that the PoE splitter is technically only rated for 1 GbE. So use as short patch cable as possible and ideally CAT6.
Still few things to tidy up and perhaps I could build this into a nice Pelican case
Has your bike suddenly lost its Wi-Fi connection after a Peloton software update? Is it saying “Device not connected to internet”?
Here is why and how to fix it before it hopefully gets fixed in one of the upcoming Peloton software updates.
Peloton bikes use Android operating system, and they have recently upgraded to Android 10. Unfortunately, this version has compatibility issues with Cisco Wi-Fi access points and Adaptive Fast Transition feature, which is enabled by default.
To resolve the issue, simply set Fast Transition to Enabled.
Connect to your Wireless LAN Controller, go to Configuration > Tags & Profiles > WLANs > select the network > click Edit > Security > Layer2 > Fast Transition > Enabled > Update & Apply To Device. Now, test that your bike can connect, and test few other devices to make sure everything is working as expected. Then click the floppy disk icon to save this new configuration.
After using FriendlyElec R5S single-board computer as a portable iperf3 server, I decided to also order and test Topton M6 Mini PC. It is more powerful, based on Intel CPU, and runs Windows 11 Pro or Ubuntu. I personally chose Windows (yes, I am brave), mainly because I also wanted to use this device as a Windows Wi-Fi client for other things than iperf3 testing.
Dimensions and case
Compared to the R5S, Topton M6 Mini PC is still portable, but about twice as large. Plastic case wraps the unit, but it is more fragile if you plan to carry it in your backpack or tool bag. There is a built-in fan which is always on. Not a big deal if you use it as an perf3 server, but little inconvenient when it runs on your desk for a longer period of time.
iperf3 performance
Topton M6 has a single onboard 2.5 Gigabit Ethernet port consistently capable of 2.35 Gbps up and down iperf3 throughput with default settings.
Consistent 2.35 Gbps iperf3 throughput
Now, can we make it go faster? Let’s see. We will use USB-A 5 Gigabit Ethernet capable Sabrent adapter. This can either be connected to a USB-A port or USB-C port of the Mini PC. In my tests, I have found that the USB-C port has limited throughput and only tops around 350 Mbps. When I connected the Sabrent 5GbE adapter to USB-C, it only auto negotiated 1 Gbps Full Duxplex.
Use any of the three USB-A 3.1 ports instead to avoid that limitation.
Use USB-A ports, not the USB-C With the USB adapter, we get 2.94 Gbps down and 3.27 Gbps up
With the USB adapter, the whole setup get less portable. But it allows us to achieve 2.94 Gbps down and 3.27 Gbps up from clients perspective. Is it worth the extra spend? If you need to break the 2.35 Gbps barrier of the built-in 2.5 GbE port, this might be a workable solution for you.
Power adapter with an adapter
This Mini PC is quite strict when it comes to its power source. It requires 12V/2A USB-C PD adapter. Unfortunately, your USB-C MacBook or iPad chargers won’t work.
It draws around 7.5 Watts in idle mode.
If you happen to only use this PC in the US, happy days, as the power adapter ships with US plug. If you select UK during the ordering process, you will receive the US power adapter with UK adapter, which adds to its overall size.
My way around this is to use a standard non-USB-PD 12V/2A adapter with 5.5×2.1mm barrel jack connector, and a barrel jack to USB-C adapter. This particular “power brick” has a standard IEC C14 power cable connector, which you can find in any data centre and with the right European, UK, or Australian plug.
Power adapter with barrel jack + barrel jack 5.5×2.1mm to USB-C adapterDetail of barrel jack 5.5×2.1mm to USB-C adapter
Battery power
Simply use a USB-C cable and USB PD battery pack capable of delivering 12V/2A. No surprises there.
Powered by PoE
I prefer powering equipment using PoE over local power bricks. If you are in the same boat, you can power this Mini PC by a PoE splitter.
Please pay close attention to the splitter specs. We want the one with a barrel jack and 12V/2A. Since the Mini PC uses USB-C power connector, we will use a barrel jack 5.5×2.1mm to USB-C adapter. Here is the complete setup. Press the power button and voila!
Under the hood
Most of the components are soldered to the main board with little room for upgrades. I ordered the lowest 8GB DDR4 and 128GB NVMe spec with Windows 11 Pro OEM preinstalled (no actual Windows license included).
I was hoping for the Wi-Fi adapter to be replaceable, but it is not the case. It is Intel AX201 and soldered to the board. Good enough, just not ideal for Wi-Fi professionals. M.2 slot would be ideal.
A quick look at the bottom side of the PCB shows the NVMe drive.
NVMe drive is practically the only replaceable component
Final verdict
Personally, I think this Mini PC has some great potential for certain use cases, but as an iperf3 server, I would rather use the FriendlyElec NanoPi R5S I reviewed here.
If you absolutely need to break the 2.3 Gbps barrier, it can be done with the help of a USB 5 GbE adapter, but it is not very cost effective. The Mini PC cost me £186 including shipping to the UK. The Sabrent 5GbE USB adapter costs around £65.
Finally, it you need top performance, don’t care that much about small form factor, and money is no object, the latest Apple M1 Mac Mini can be configured with built-in 10 GbE.
