All posts by firas.shaari

Introduction: The Quest for Uninterrupted Connectivity

At 802.11 Networks Corp, we’re driven by a passion for Enterprise Wireless. We believe in demystifying complex topics, diving deep into the technical intricacies, and presenting our findings in a way that sparks conversation and propels industry-wide improvements. Today, we’re focusing on a critical aspect of modern living: Wi-Fi roaming in Multi-Dwelling Units (MDUs).

Think bustling apartment complexes, vibrant student housing, comfortable senior living facilities, and modern condominiums. Why this focus?

• Ubiquity of MDU Living: A significant portion of the population resides in MDUs. In the US, estimates range from 30% to 42%, highlighting the sheer scale of this living arrangement.
• The Promise of Managed Wi-Fi: MDUs offer a unique opportunity for property-wide, managed Wi-Fi solutions. When implemented effectively, these systems deliver substantial technical and economic advantages to residents.

A cornerstone of a successful managed Wi-Fi deployment is seamless roaming. Residents expect their connected devices to transition smoothly between access points (APs) as they move throughout the property. This eliminates frustrating disconnections and ensures a consistent user experience.

In this post, we’ll dissect common MDU deployment architectures, exploring their strengths and weaknesses. We’ll start by differentiating between managed and non-managed environments, then delve into four specific client authentication and roaming scenarios. Our goal is not to declare a “winner” but to foster a constructive dialogue that enhances human connectivity.

Understanding MDU Wi-Fi Architectures

To fully understand the results of the performance test, we must first understand the architectures that are being tested.

1. Traditional Residential Deployments: The “Home Router” Approach

• Each apartment operates its own dedicated home router.
• These networks typically feature:
  • A private SSID secured with WPA2-Personal for individual residents.
  • A universal SSID, often utilizing Passpoint with pre-installed profiles, enabling limited roaming across the complex.
• Technical Characteristics:
  • NAT (Network Address Translation) is standard, isolating each apartment’s network.
  • 802.11r (Fast Transition) is generally absent.
  • Some APs may implement key caching to expedite re-authentication for returning devices.
• Limitations:
  • Limited roaming performance.
  • Interference between many routers.
  • Difficult to manage as a whole.

2. Managed MDU Deployments: Centralized Control

• A professionally designed RF network covers the entire property.
• APs are strategically placed based on a thorough RF survey, ensuring optimal coverage.
• A single, unified SSID is broadcast throughout the property.
• Technical Characteristics:
  • VLANs (Virtual Local Area Networks) are employed to segregate resident traffic, ensuring privacy and security.
  • Authentication options include:
    • Passpoint-like systems with pre-installed profiles (ideal for smartphones and laptops).
    • Multi-PSK (MPSK) solutions with RADIUS authentication (offering a balance of security and ease of use, and better IoT compatibility).
• Key Points:
  • Allows 802.11r to be implemented
  • Centralized management and troubleshooting.
  • Enhanced security and privacy relative to using a single, shared PSK.
  • Ability to fine tune the network.

Quantifying Roaming Performance: The Test Bed

To objectively assess roaming performance, we constructed a test bed that replicated the scenarios described above. We distilled the myriad of possible configurations into four representative cases:

1. WPA2-Enterprise (TLS) + Bridged + 802.11r:
   • Represents a managed MDU with Passpoint or similar pre-installed profiles.
   • Bridged network: Clients retain their IP address during roaming.
   • 802.11r: Rapid authentication using R1 keys distributed via the Distribution System (DS).
2. WPA2-Enterprise (TLS) + NAT’d + Key-Caching:
   • Mirrors the universal roaming SSID in traditional residential deployments (e.g., Xfinity Mobile Hotspot).
   • NAT’d network: DHCP lease renewal and Layer 3 (L3) connection break during roaming.
   • Key caching: Speeds up re-authentication for returning clients, but no 802.11r.
3. MPSK-RADIUS + Bridged + 802.11r (or Key-Caching):
   • Represents a managed MDU with MPSK and RADIUS authentication.
   • Bridged network: Maintains L3 connection.
   • 802.11r availability based on capabilities of backend MPSK solution used
   • Each resident gets a unique PSK tied to a VLAN.
4. MPSK-RADIUS + NAT’d + Key-Caching:
   • While less common, it was tested to provide a complete view.
   • NAT’d network.
   • Key Caching.

The Test Setup: Precision and Control

• Two Enterprise OpenWiFi APs broadcasted the four SSIDs, each corresponding to a test case.
• The APs were connected to a Linux-based router (providing DHCP, RADIUS, and NAT) via a switch.
• FreeRADIUS was used for RADIUS authentication.
• All tests were conducted in RF isolation chambers to ensure accuracy.
• Roaming events were manually triggered for consistent results.

Test Architecture Diagram:

Test Execution: Measuring Roaming Dynamics

• Each test began with a pre-authenticated client connected to AP1.
• A continuous ping to 8.8.8.8 (Google DNS) was executed with a 1-second interval.
• Four manual roaming events were triggered during the 100-ping test.
• Latency and packet loss were recorded for each scenario.

Results: A Clear Picture of Performance

• WPA2-Enterprise (TLS) + Bridged + 802.11r:
  • Packet Loss: 4%
  • Average Latency: 16.98 ms
• WPA2-Enterprise (TLS) + NAT’d + Key-Caching:
  • Packet Loss: 12%
  • Average Latency: 19.91 ms
• MPSK-RADIUS + Bridged + 802.11r:
  • Packet Loss: 1%
  • Average Latency: 18.20 ms
• MPSK-RADIUS + NAT’d + Key-Caching:
  • Packet Loss: 9%
  • Average Latency: 18.07 ms

Analysis and Conclusion: Optimizing MDU Wi-Fi

Why Roaming Matters: Seamless roaming is essential for a positive user experience in MDUs. Disruptions lead to frustration and decreased productivity.

Best Solutions:

• Managed MDUs:
  • Regardless of the authentication method (MPSK/WPA2-Enterprise), Bridged networks with 802.11r offer excellent performance.
  • MPSK-RADIUS with VLANs adds user-friendlinesss for IoT devices
• Traditional Residential:
  • NAT’d networks with key caching are common, but less ideal.
  • Requires separate, universal SSID for Roaming across property.

Client Considerations:

• Passpoint benefits devices with pre-installed profiles.
• MPSK-RADIUS accommodates IoT and other devices with limited capabilities.

Comparison Matrix:

Feature	WPA2-Enterprise (TLS) + Bridged + 802.11r	WPA2-Enterprise (TLS) + NAT’d + Key-Caching	MPSK-RADIUS + Bridged + 802.11r	MPSK-RADIUS + NAT’d + Key-Caching
Network Mode	Bridged	NAT’d	Bridged	NAT’d
Roaming Support	802.11r	Key-Caching	802.11r (partial)	Key-Caching
Authentication	Passpoint (pre-installed profiles)	Passpoint (pre-installed profiles)	MPSK	MPSK
Traffic Segmentation	VLANs	Per-user NAT	VLANs	Per-user NAT
Packet Loss	4%	12%	1%	9%
Average Latency (ms)	16.98	19.91	18.20	18.07
Best Use Case	Managed MDU, devices with Passpoint profiles	Traditional Residential Model (Separate NAT’d Home Router per unit)	Managed MDU, diverse client device types	Less Common deployment use cases. TBD.
Pros	Lowest latency, seamless roaming	Simpler NAT isolation	Very low packet loss, diverse client ecosystem	TBD
Cons	Passpoint reliance can limit IoT device support	Higher packet loss, DHCP renewals	Partial 802.11r support	Higher packet loss compared to Bridged 802.11r

Key Takeaway: By understanding these technical nuances, Professional WLAN experts, like 802.11 Networks Corp, can help ISPs & MDU Network Operators to deliver exceptional roaming experiences.

As part of our ongoing research at 802.11 Networks, the team conducted an in-depth traffic shaping and QoS (Quality of Service) test to evaluate how different traffic prioritization strategies perform in real-world conditions. This research aims to help our customers better understand their networks and make educated decisions on configurations that ensure optimal performance.

Test Setup Highlights:

• Total Clients: 30
  • Zoom Clients: 3 (Simulating Zoom calls with 3Mbps uplink and downlink traffic per client)
  • Streaming Clients: 27 (Simulating video streaming with uplink traffic ranging between 128Kbps–2Mbps and downlink traffic between 1.5Mbps–30Mbps)
• Protocol: TCP
• Environment: OTA testing inside an RF isolation chamber for accurate and interference-free results
• Access Point: CIG WF196, running OpenWiFi v3.2.0
• Channel: 48/20MHz
• Average RSSI: -60dBm
• WAN Configuration: Simulated Cable Modem link using Linux TC, with 20Mbps uplink and 1000Mbps downlink to replicate a typical Comcast subscription
• AQM:
  • FQ-CoDel
  • CAKE

The test environment included a traffic generation server connected to the AP’s WAN link via a Linux box simulating the Cable Modem WAN link. This controlled environment allowed us to precisely measure the effects of various QoS configurations on network performance.

Test Cases Conducted:

• FQ-CoDel with no DSCP marking: Default case with no configurations.
  
  

WAN link Traffic

Zoom Client1 Throughput

Zoom Client1 Latency

Zoom Client2 Throughput

Zoom Client2 Latency

Zoom Client3 Throughput

Zoom Client3 Latency

WAN Link Traffic

Zoom Client1 Throughput

Zoom Client1 Latency

Zoom Client2 Throughput

Zoom Client2 Latency

Zoom Client3 Throughput

Zoom Client3 Latency

• CAKE with eBPF reclassification: No DSCP marking from side clients, but downlink traffic reclassified as CS5 using eBPF programs running in the AP kernel.

WAN Link Traffic

Zoom Client1 Throughput

Zoom Client1 Latency

Zoom Client1 Throughput

Zoom Client2 Latency

Zoom Client3 Throughput

Zoom Client3 Latency

• CAKE with eBPF reclassification + marked uplink : Zoom clients’ uplink traffic tagged with DSCP CS4, and downlink traffic reclassified as CS5 using eBPF programs on the AP kernel.

WAN Link Traffic

Zoom Client1 Throughput

Zoom Client1 Latency

Zoom Client2 Throughput

Zoom Client2 Latency

Zoom Client3 Throughput

Zoom Client3 Latency

In all test cases, 802.11e WMM was enabled on the AP to allow for hardware-assisted prioritization of traffic.

Key Takeaways:

• Case 4 consistently delivered the best results, with:
  • Improved guaranteed throughput for the Zoom clients’ vs the streaming clients
  • Reduced latency for Zoom clients, ensuring call quality
• These results highlight the power of combining advanced queuing mechanisms like CAKE with intelligent traffic classification using DSCP and eBPF.

Why This Matters: At 802.11 Networks, we specialize in wireless testing and performance optimization. This research underscores our commitment to helping customers achieve enterprise-grade performance using open-source hardware and intelligent network configurations. By understanding how QoS mechanisms like AQM, DSCP tagging, and WMM affect real-world traffic, network administrators can make informed decisions to enhance user experiences and ensure their networks perform at their peak.

If you’re interested in learning more about these tests or how they can be applied to your network, feel free to reach out or follow for updates.

The OnePlus 12 offers a feature called “Dual WiFi Acceleration” under the WiFi Assistant page, claiming to achieve faster internet speeds by connecting to two WiFi networks simultaneously.

To evaluate this claim, I set up an OpenWiFi CIG WF-196 AP, a 4×4 WiFi 6e access point (AP) with support for 160MHz bandwidth on 6GHz, 80MHz on 5GHz, and 40MHz on 2.4GHz. I configured distinct SSIDs for each band:

• WF-196-6G for 6GHz on channel 33 with 160MHz bandwidth
• WF-196-5G for 5GHz on channel 116 with 80MHz bandwidth
• WF-196-2G for 2.4GHz on channel 1 with 40MHz bandwidth

To maximize performance, I paired the OnePlus 12 with the AP using the 6GHz and 2.4GHz bands within an RF isolation chamber.

Although the OnePlus 12 is WiFi 7-capable, this setup does not leverage Multi-Link Operation (MLO). Instead, the phone establishes two separate physical connections over different radios. It appears to use some sort of load-balancing algorithm to optimize throughput across both links.

Using ADB commands and screen mirroring, I ran a speed test to a local Open SpeedTest server hosted on my router. In the video below, you can see how the phone successfully establishes two physical connections, one on wlan0 and the other on wlan1. The “iw dev wlan0/1 link” command outputs, refreshed every second, display packets sent and received over both interfaces.

However, the results were somewhat underwhelming. While the phone successfully maintained connections on both the 6GHz and 2.4GHz bands, traffic was rarely transmitted over both bands simultaneously. As shown in the video, almost all packets during the speed test were sent and received on the 6GHz link.

Another noteworthy observation was the failure of the 2.4GHz link to reach its expected PHY rate of 573.5Mbps on the uplink, despite the short distance and high RSSI. This may be due to degradation in beamforming due to maintaining simultaneous connections on both the 6GHz and 2.4GHz bands.

Despite these limitations, the Dual WiFi Acceleration feature holds promise. If optimized correctly, it could offer WiFi 7-like performance, similar to MLO, on legacy APs.

Want to know which enterprise class Wi-Fi Access Point offers the best value for your enterprise network?

We recently pitted the Ruckus R350 against the Edgecore EAP101 (running OpenWiFi firmware) in a series of rigorous tests. Here’s what we found:

Setup Environment:

The testing was conducted Over-The-Air (OTA) within an RF isolation chamber to ensure minimal interference and consistency. Both the Ruckus R350 and Edgecore EAP101 were tested on channel 112 with a 20MHz bandwidth.

Equipment Used:

• LANforge: Used to simulate traffic loads.
• RSSI Level: Set at -40 dBm for both APs during the capacity test.
• Attenuation Levels: 0-50dB to cover the RSSI dynamic range between -40dBm to -85dBm.

Observations:

• Range vs. Rate Test: Both APs performed similarly with the Intel BE200 client across attenuation levels. However, after 20 dB of attenuation, the R350 exhibited a slight dip in throughput performance compared to the EAP101.

• Capacity Test: As the number of clients increased, both the EAP101 and R350 maintained a similar performance. However the EAP101 began to show a slight advantage (~7Mbps) once the client count surpassed 40.

Conclusion:

It’s clear that both access points delivered solid results here, however subtle differences emerged as we turned up the heat! The Edgecore EAP101, running the OpenWiFi firmware stack, delivered superior performance when compared to the incumbent Ruckus Unit. The EAP101’s ability to maintain throughput as conditions deteriorated highlights its clear value for organizations looking for a cost-effective solution that still delivers performance on par with the industry’s best!

At 802.11 Networks, we combine deep industry domain knowledge with cutting edge tools to ensure our clients are successful.

If you’re ready to transform your wireless network, reach out and let 802.11 Networks deliver a tailored solution that drives results. Our expertise and advanced tools will help you achieve your goals.

#accesspoints #networkperformance #wifi #technology #enterprise #80211Networks #testing #ruckus #TIP #OpenLAN

Recently, solutions offering MPSK-RADIUS services have gained traction in various deployment environments, including MDUs, parks, and venues. These systems provide a versatile solution, enabling user authentication, accounting, and attribute assignments such as VLANs, rate limiting, and quotas, all without requiring EAP support.

Some solutions, like those built on Passpoint 2.0, offer a smoother user experience by enabling seamless connectivity with zero user intervention. However, these solutions require EAP support, which is often lacking in low-end devices such as IoT devices. As a result, these devices cannot take advantage of the benefits provided by Passpoint 2.0-based solutions.

On the other hand, MPSK-RADIUS systems are based on the most common and basic security protocol in Wi-Fi, PSK (Personal), which is supported by virtually every device. In MPSK-RADIUS deployments, from the client’s perspective, there is no visible RADIUS server. Clients perform simple WPA or WPA2 Personal authentication using passphrases entered by the users.

In a traditional MPSK-RADIUS system, the AP does not have knowledge of the passphrase. Instead, a RADIUS server is configured with a list of MAC addresses and their corresponding passphrases. When a new client tries to connect to the AP, it goes through the open system authentication and association processes. Afterward, the AP initiates the 4-way handshake:

• The AP sends EAPOL-Key message 1, which contains the ANonce.
• The client generates the SNonce and, using it alongside the passphrase (which is expanded based on the SSID to become the PMK, where PMK = f(PSK, SSID)), generates the PTK and its derivatives (KEK, KCK, and TK).
  • PTK = f(PMK, Client MAC, BSSID, ANonce, SNonce)
• The client installs the PTK, constructs EAPOL-Key message 2 by adding the SNonce, and uses the KCK to calculate a MIC for the message payload.
• In a typical WPA2 Personal scenario, the AP would use the same inputs to calculate the PTK and verify the MIC based on the KCK. However, since the passphrase is stored on the RADIUS server, the AP forwards the entire content of EAPOL-Key message 2 to the RADIUS server in an Access-Request message.
• The RADIUS server searches for a matching MAC address in its list. Once a match is found, it uses the passphrase and the information from EAPOL-Key message 2 to calculate the PMK. The RADIUS server then sends the PMK to the AP in an Access-Accept message.
• With the PMK, the AP can either use the existing ANonce and SNonce to calculate the PTK and its derivatives or restart the 4-way handshake procedure to obtain new values. This decision typically depends on the configured timeout between EAPOL-Key messages and the time it takes for the RADIUS server to respond with the Access-Accept message.
• The remainder of the process follows the standard 4-way handshake. The AP installs the PTK, generates the GTK (if this is its first client), encrypts it with the PTK, and sends it in EAPOL-Key message 3.
• The final message, EAPOL-Key 4, is sent by the client to acknowledge the receipt and installation of the GTK.
  

This setup works well in controlled environments where the network administrator has a pre-populated list of all client MAC addresses. This scenario is common in enterprise networks where EAP is the primary authentication method, and MPSK-RADIUS is used to onboard IoT devices that do not support 802.1X.

However, a traditional MPSK-RADIUS setup is impractical in environments where the administrator has no control over the devices users bring to the network. A prime example is MDU networks, where the admin needs to manage a pool of PSKs that are not tied to a one-to-one mapping with specific MAC addresses. The system must allow users to authenticate with their assigned PSK, regardless of the MAC address of the device they are using to connect to the network.

MPSK with RADIUS systems offers a solution to the problem mentioned above. These solutions typically consist of multiple components that provide various services. Some of these components include:

• RADIUS server for authentication and accounting.
• Databases to manage pools of PSKs and PMKs.
• Captive portal services for user interaction and onboarding.
• SMS gateways to assist with new customer onboarding.
• User portal for customers to manage their subscriptions and change their passwords without requiring network admin intervention.

The workflow for an MPSK-RADIUS solution is similar to the traditional MPSK-RADIUS setup described above, with one key difference: instead of matching the MAC address of the authenticating client to a list of one-to-one MAC-to-PSK pairs, the system calculates the PTK and MIC for all PSKs in the pool and tests them against the MIC sent by the AP in EAPOL-Key message 2. When a match is found, the system forwards the corresponding PMK to the AP. Once the AP receives the PMK, it has two options:

• Create the GTK and build EAPOL-Key message 3: The AP generates the Group Temporal Key (GTK) if this is the first client or if a new GTK is needed. It then builds EAPOL-Key message 3, encrypts the GTK with the PTK, and sends it to the client.
• Restart the 4-way handshake: If the time spent waiting for the Access-Accept message with the PMK exceeds the timeout for the 4-way handshake, the AP will restart the handshake process. This ensures that fresh ANonce and SNonce values are used, allowing the process to complete successfully.
  

One major downside to the process described in the flowchart above is that every time a device roams to a new AP, it must undergo a full RADIUS authentication, which usually takes about one second. A roaming time of one second is unacceptable, as it can disrupt most Layer 3 (L3) connections. To address this, OpenWiFi enables PMKSA key caching for when the client re-roams back to the original AP and supports Fast Transition (FT) with MPSK-RADIUS or PSK-RADIUS when roaming to a new AP. The FT process can be summarized as follows:

• Client initiates the roaming process by scanning for the next best candidate AP.
• Client confirms FT support: The client checks whether the target AP supports Over-The-Air (OTA) or Distribution System (DS) FT transition roaming.
• For Over-The-Air (OTA) FT:
• Authentication exchange: The client and the target AP exchange FT Authentication frames. The client shares its SNonce, PMK ID, PMK-R0 ID, and Mobility Domain ID with the target AP. In return, the target AP provides its ANonce, PMK ID, PMK-R0 ID, PMK-R1 ID, and Mobility Domain ID.
• Association exchange: The client and the target AP exchange Association and Reassociation frames. In the Association frames, the client includes the same information as above, along with a MIC generated on the message payload. In the Reassociation frames, the target AP includes the same information plus the GTK.
• For Distribution System (DS) FT:
• Authentication exchange: The same information is exchanged in the Authentication frames as in OTA FT, but instead of being sent over the air, the data is embedded in an Action Frame sent to the current AP. The current AP forwards this frame over the distribution system to the target AP. The target AP replies to the client via the distribution system through the current AP.
• Association and Reassociation exchange: The Association and Reassociation frames remain unchanged, and the procedure follows the same steps as in the OTA case.

The packet capture screenshots below illustrate how PMKSA key caching and Over-The-Air (OTA) Fast Transition (FT) with MPSK-RADIUS reduce authentication time from approximately 1 second to around 50 milliseconds.

• Go to Settings -> About device -> Version, and tap on “Version number” 7 times, this should enable the developer mode.
  
  
  

• Go to Settings -> Additional settings -> Developer Options, and enable “USB debugging” and “OEM unlocking”.
  
  

• To communicate with the OnePlus phone we will need to install the command-line tool adb (Android Debug Bridge). On a MacOS this can be installed using HomeBrew.
  
  

firasshaari@MacBook-Pro-9 ~ % brew install android-platform-tools

• Connect the device to your laptop using a USB-C to USB-C or USB-C to USB-A cable. Now, you should be able to see your device listed under the connected devices.
  
  

firasshaari@MacBook-Pro-9 ~ % adb devices   
List of devices attached
76f80f11	device

• Reboot the device in the bootloader mode using the below command.
  
  

firasshaari@MacBook-Pro-9 ~ % adb reboot bootloader

• Now in the bootloader mode your device should have a similar screen to the photo below except, its bootloader is still in the locked state.
  
  

• Now using either one of the 2 commands listed below your phone will prompt you that you’re about to unlock the bootloader. Once you accept that, the device will reboot and a message stating that the device cannot be trusted and you will need to set up it again from scratch.
  
  

firasshaari@MacBook-Pro-9 ~ % fastboot oem unlock
firasshaari@MacBook-Pro-9 ~ % fastboot flashing unlock

• After setting up your device, we will need to install the Magisk APK to allow for super user access on the device. Download Magisk-v27.0.apk and push it your device’s SD card using the following command.
  
  

firasshaari@MacBook-Pro-9 Downloads % adb push Magisk-v27.0.apk /sdcard/Download/ 
Magisk-v27.0.apk: 1 file pushed, 0 skipped. 42.2 MB/s (12498796 bytes in 0.282s)

• Use the Files app on the device to install the Magisk APK. In my case you can see that the device is trying to update the already installed APK
  
  

• After installing the APK you should be greeted with a similar screen the one below. The only difference between my screenshot and yours will be that you haven’t installed Magisk yet.
  
  

• We will need to download a FW image for the OnePlus. Pay attenuation to your HW version, since they are different images for different regulatory domains. I found the FW images on this XDA forum post.
  • Download FWs images from XDA form
• I uploaded the North America images to my OneDrive. you can find them in the links below. In my case I used OxygenOS-CPH2583_14.0.0.404(EX01)A.57 image.
  • OxygenOS CPH2583_14.0.0.502(EX01) A.61 + OxygenOS CPH2583_14.0.0.502(EX01) A.61_Incremental
  • OxygenOS CPH2583_14.0.0.604(EX01)
  • OxygenOS-CPH2583_14.0.0.404(EX01)A.57
• Download the Payload Dumper and follow the installation steps in the ReadMe file. This will be used to extract the “init_boot.img” file from the FW image. In my case this version payload-dumper-go_1.2.2_darwin_amd64 worked on my 2023 MacBook Pro 14″.
• Copy the “init_boot.img” file to your device using the push command.
  
  

firasshaari@MacBook-Pro-9 ~ % adb push init_boot.img /sdcard/Download/

• Open Magisk on the device, click on the “Ramdisk” install and “Select and Patch a File” and select the “init_boot.img” file that we pushed to the device in the last step.
  
  

• Using the adb pull command, pull the generated patched “init_boot.img” file from your phone to your laptop.
  

firasshaari@MacBook-Pro-9 ~ % adb pull /sdcard/Download/magisk_patched-27000_Y3vcR.img

• Now reboot the device in the bootloader mode and flash the patched image.
  
  

firasshaari@MacBook-Pro-9 ~ % adb reboot bootloader
firasshaari@MacBook-Pro-9 ~ % fastboot flash init_boot magisk_patched-27000_Y3vcR.img

• Reboot the device and if all goes well Magisk should be installed and, at this point and you should have root access on the device. It can be seen in the example below how running iw commands fails at first but after acquiring root privileges using the su command the command is executed successfully.
  
  

firasshaari@MacBook-Pro-9 ~ % adb shell
OP595DL1:/ $ iw wlan info 
/system/bin/sh: iw: inaccessible or not found
127|OP595DL1:/ $ su
1|OP595DL1:/ # iw wlan0 info                                                                                                                                                                                                                                               
Interface wlan0
	ifindex 24
	wdev 0x1
	addr 8e:f1:ad:a1:a6:71
	ssid home
	type managed
	wiphy 0
	channel 36 (5180 MHz), width: 80 MHz, center1: 5210 MHz
	txpower 20.00 dBm
OP595DL1:/ # 

• To turn the OnePlus 12 into sniffer mode, execute the following commands on adb shell.

iw phy phy0 interface add mon0 type monitor 
ip link set wlan0 down 
ip link set mon0 up 
ip link set wlan0 down
iw dev mon0 set channel 36 
tcpdump -i mon0 -envvv 

Useful Links

• http://junsun.net/wordpress/2024/04/how-i-rooted-oneplus-12-with-magisk/
• https://topjohnwu.github.io/Magisk/install.html
• https://xdaforums.com/t/oneplus-12-rom-ota-boot-oxygen-os-repo-of-oxygen-os-builds.4657465/
• https://github.com/vm03/payload_dumper
• https://github.com/ssut/payload-dumper-go/releases
• https://github.com/topjohnwu/Magisk/releases/tag/v27.0

In today’s diverse networking environments, there’s a growing trend towards combining proprietary vendor solutions with open-source alternatives to achieve a balance of reliable performance and cost-effectiveness. This article explores this idea by demonstrating a Multi-Pre-Shared Key (MPSK) Wi-Fi solution using both Juniper APs and OpenWiFi APs, where authentication and accounting is managed through FreeRadius server.

The Network Setup

At the heart of the network, we have the 3.0 version of the FreeRadius server—an open-source solution capable of handling authentication for a variety of devices which I am running on my home NUC Ubuntu box, alongside a ISC-DHCP-Server to handle DHCP requests, and some iptables NAT rules to nat clients to the outside world . In this scenario, we’re looking at the Juniper AP45 and the TIP OpenWiFi CIG WF-196, both are configured through their cloud controller and added as clients within the FreeRadius’s clients.conf file.

# Juniper AP45
client a83a79a8367e {
    secret = secret
    ipaddr = 10.0.122.18
}

# OpenWiFi WF-196
client d4babaa1484 {
    secret = secret
    ipaddr = 10.0.122.23
}

For continuous roaming tests between these two APs, the Candela LANforge WiFi Roam test is employed. The test basically allows the user to construct a script that can run for a set amount of time or indefinitely. The operator can determine where, when, and how long the client should roam.

Configuring MPSK

The MPSK configuration requires minimal adjustments on the FreeRadius server. For each device, the MAC address and the PSK are entered into the users file:

# LANforge AX210
e8f4080324ba Cleartext-Password := "e8f4080324ba"
        Tunnel-Type = 13,
        Tunnel-Medium-Type = 6,
        Tunnel-Private-Group-Id = 1000,
        # Expected PSK for OpenWiFi using the tunneled password attribute
        Tunnel-Password = 12345678,
        # Expected PSK for Juniper in a Cisco AVPair attributes
        Cisco-AVPair = "psk-mode=ascii",
        Cisco-AVPair += "psk=12345678"

Notably, TIP OpenWiFi APs require the Tunnel-Password attribute, while the Juniper APs utilize the Cisco-AVPair attributes. The 2 different approaches show case how an homogenous ecosystem can be built by integrating proprietary and open source solutions with a universal authentication system like FreeRadius.

Mixed Ecosystem Benefits

The merger of TIP OpenWiFi and proprietary solutions like Juniper’s APs provides numerous benefits:

• Cost Efficiency: TIP OpenWiFi APs like the WF-196 are significantly more affordable than many proprietary solutions and can sometimes be the only realistic solution in industries with limited budget. A simple comparison of the two APs demonstrates why the open source solution might be a game changer for industries where budgets are limited.

• Flexibility: TIP OpenWiFi’s open-source nature allows for extensive customization and integration. The open source code allows for customizations that might not be available with the vendor locked solution.
• Innovation: Proprietary solutions often come with advanced features and robust support, while open-source projects bring community-driven innovation. As a member of the OpenWiFi community you have the opportunity to lead the development of new features on corner cases that the vendor might not be interested in developing.

Configuraing The OpenWiFi Controller: An SDK with a UI

The OpenWiFi controller stands out as an SDK (Software Development Kit) with a user interface, designed for developers and organizations to create their own user-friendly controllers.below we show a screenshot of the configs in a JSON file format. Not all fields have been expanded to not overwhelm the reader. Only the important parts that highlight the settings for the SSID and the RADIUS server.

The Juniper Controllers Configuration

Configuring the Juniper Controller was straightforward and uncomplicated. As someone who had never used it before, I felt as if I had been using it for years. Every configuration was where you expected it to be, and the transitions between steps were effortless.

Running the Test.

The brief movie below shows a wireless STA managed by the Canddela LANforge roaming between the AP45 (channel 48) and the WF-196 (channel 44). Two additional radios were utilized as sniffers to catch the traffic. An EAPOL display filter was employed to separate the 4-Way Handshake from the rest of the air traffic.

I did not get into the specifics of how to set up a FreeRadius server or the more in-depth aspects of the Juniper Mist MPSK setups because that was not the purpose of this article. If you need assistance with the issues listed above, please see my wonderful friend Mohammad Al‘s post at https://artofrf.com/2024/04/02/mist-mpsk-with-freeradius/.

Recently, the development team at OpenWiFi has added a DHCP-Relay feature to the OpenWiFi firmware. I worked with the Q&A team to come up with a test plan for the feature. At first it sounded straight forward. All we have to do is capture the DHCP request packets leaving the AP and verify whether they are sent out as broadcast or unicast. The other aspect we needed to verify was that under option 82 the development team allowed for 3 values to be forwarded to the DHCP server under the 1st and 2nd sub-options, (Agent Circuit ID and Agent Remote ID) the SSID, the VLAN, or the AP MAC address but, this could also be verified with the same simple Wireshark capture.

This is all good but, is it enough? Does that mean that the DHCP-Relay will work as a part of an ecosystem? Will the DHCP server recognize the information sent under option 82 and filter clients accordingly ? Those questions made me realize that a simple capture is insufficient to guarantee whether or not this new feature actually works. We needed to come up with a scenario where this feature is tested under real world conditions. A test plan that mimics how this feature will be used in the field.

But, first let’s take a step back and refresh our memory on what does a DHCP Relay do and why is it important ? For a client to obtain an IP from a DHCP server it has to go through the DORA frame work.

The process starts with broadcasting a Discover packet with a destination address 255.255.255.255. If there is an active DHCP sever on the same VLAN or subnet it will reply with an Offer message and the client and server go through the DORA framework. However, sometimes the DHCP server is on a different VLAN or sets in the cloud serving many locations at once. We all know that broadcasts are dropped by the routers so how can a client reach a DHCP server that doesn’t live on the same subnet. This is where the DHCP-Relay comes into play. The DHCP-Relay intercepts the Discover packet and transform it on behave of the client from a broadcast to a unicast that targets a specific preconfigured DHCP server.

Considering all of the above, it was time to get to the whiteboard. I decided to use my home network as the ground for testing. My home router which is just an Ubuntu NUC running linux will act as the NAT router for 2 new VLANs 100, and 200 (along side my native VLAN subnet 10.0.0.0/16 that I use for my home devices and AP and switches management interfaces). My Ubuntu server will provide DHCP pools for the 2 new VLANs through ISC-DHCP-Server service. I needed a switch to tie it all together so I bought a managed L3 TP-Link switch (TL-SG2008P). I created VLANs on it and connected everything together.

I configured the OpenWiFi AP to act as the DHCP-Relay for any clients connected on the 2 SSIDs I created, WAN100 and WAN200 (WAN100 -> VLAN100, WAN200-> VLAN200). I also configured the DHCP-Relay to include the SSID name under the 1st sub-option of option 82. The reason for that is to use this piece of information as the basis for filtering. The DHCP server will decide on what pool should the clients gets its IP from.

The real challenge laid with understanding and configuring the ISC-DHCP-Server to distinguish between the different request and assign the correct IP address.

I created 2 classes to filter sub-option1 under DHCP option 82. I used the allow and deny statement to filter which pool should serve each VLAN. I deep dove into the packet capture to find out the offset and length of the information included in sub-option 1 to input the correct values for the match if condition statement. This required a capture of the unicast DHCP Discover packet and finding out the number of bytes included in the sub-option.

All was left now if to create 2 STAs and connect each one to a different SSID on the AP and hope they get the correct IP addresses. I took me around 3 days to perfect the setup but at the end the 2 virtual STAs I created on my Candela LANforge box acquired the correct IP addresses with respect to the SSIDs they were connected to.

The DHCP-Relay feature combined with the ability to filter based on the information included in option 82 on the DHCP server side opens up countless opportunities for different deployment scenarios. Clients can identified and assigned to specific pools based on many different aspects. For example, one can include the AP MAC to differentiate clients based on their physical location, or assign variable lease times based on whether this is a guest or employee VLAN.

As a new fan for home automation, I’ve recently started a journey to install several IoT devices that improve the convenience and effectiveness of my daily life. 95% of those devices are 2.4GHz only, which has a unique set of challenges to begin with. A few of the gadgets I have so far installed are a Govee water leak detector, a Ring Amazon Camera, and TP-Link light switches and plugs. Unfortunately, when Proxy-ARP was enabled on my personal OpenWiFi APs setup, I had an issue where some IoT devices were unable to receive IP addresses.

The Govee Wi-Fi gateway and the Amazon Ring Camera were the main devices that displayed the IP address acquisition problem in the presence of active Proxy-ARP functionality on the AP. Understanding how devices behave during the IP acquiring process is crucial for identifying the root cause of this issue.

When an IoT device (or just any device for that matter) connects to a network, it requests an IP address from the network’s DHCP server. To ensure that the IP address it receives is available for use, the device sends a special type of ARP (Address Resolution Protocol) called the DHCP ARP Probe to check if any other devices on the network are using the same IP address. The expectation is that if the IP address is free, no response will be received, indicating its availability. The device may, however, think the IP address is already in use if it receives a response to its ARP Probe and declines the DHCP offer.

The IoT devices’s misbehavior manifests when Proxy-ARP is enabled on the AP. In this scenario, when an IoT device sends an ARP probe to validate IP address availability, the access point responds on behalf of the device. However, the IoT device fails to recognize that the MAC address in the response from the Proxy-ARP is its own.

As a result, the IoT device mistakenly believes that the IP address it acquired from the DHCP server is already in use since it receives a response to its ARP probe. Consequently, the device declines the DHCP offer, causing it to fail in acquiring an IP address and establishing connectivity.

On the other hand, the remaining devices (about 45 devices from different vendors) on both the 5GHz and 2.4GHz bands recognize the MAC addresses in the responses as being their own MAC addresses and accept the DHCP IP offers. When the Proxy-ARP capability is enabled, an iPhone 13 in the example below behaves as predicted.

Disabling the Proxy-ARP feature on the 2.4GHz SSID (as 90% of IoT devices can only operate on 2.4GHz) was the simplest and most direct solution to the issue. it worked… in my relatively quiet 2.4GHz home environment but, do I really want to compromise a topology design because of couple of misbehaving clients? and I can only picture the AirTime utilization nightmare that would arise in a larger, industrial, and much noisy environment.

I wanted to conduct one more test to further my conviction that this is a device-specific issue, which I was 99% certain of at this time. To my amazement, the Ring Camera functioned flawlessly with Proxy-ARP enabled on the SSID when I tested it against a Ruckus R730 AP that I had lying around. This prompted me to return to the drawing board and think about additional key factors that may have influenced the issue on the AP side.

Reading about how Proxy-ARP is implemented in OpenWiFi (or, to be more precise, the Linux kernel) and discussing the issue with the community. We uncovered that the ARP bounce-back capability is enabled by default in the Linux Kernel. This meant that the Kernel was replying back to the source of the ARP Probe and telling them they are the owner of that MAC address. Now all I had to is to disable that feature in the Kernel and Ring Camera should work with Proxy-ARP enabled.

Disabling the a feature in Kernel’s and building a new functional image may sounds like a tremendous task to take on that could weeks or even months. Imagine all the support nightmare you will have to go through with a vendor to just get such a fix included in their next release. The beauty of OpenWiFi being open-source is that you can easily reconfigure any fundamental functionality and create a new image to mitigate against any issues, like misbehaving clients for example. Utilizing the CICD pipeline of OpenWiFi to disable the ARP bounce-back feature in the Kernel, a new dev image with the Kernel ARP bounce-back feature set to disable from one of the program maintainers took only a few hours.

The fresh AP NOS image had the capacity to correct the misbehavior of a few IoT devices while utilizing less AirTime since I was able to enable the Proxy-ARP capabilities. While it fixed the issue, I wanted to also make sure there are no unintended consequences.  Running the new image through out nightly open-source 5000 test cases ensued that I had a stable image that is ready for deployment.

My objective when begin to write the article was to present an interesting technical case that could potentially save someone from losing a few days of their life attempting to troubleshoot it. By the time the draft was finished, I could clearly see how the message had evolved to emphasize how this case demonstrates the strength and potential of OpenWiFi and its transformative open and collaborative lifecycle, which gives everyone a voice, the power to directly affect and prioritize roadmaps, and the agility to ensure the stability of the ecosystem.

In today’s market, 2×2 APs are widely available, and several suppliers promote them as a less expensive, high-density deployment-capable alternative to the 4×4. On paper, 2×2 APs can theoretically offer a 2×2 client the same throughput numbers as a 4×4 one, which makes them more desirable.

The actual query is, in practice, do they realistically offer a 2×2 client the same throughput numbers? I’ve always known by heart that, a 4×4 AP has about 3dB of beam-forming gain on the downlink because of the two extra chains, and 3dB of gain on the uplink because of the MRC gain of the extra chains. That sounds wonderful, until you have to explain to someone why they should choose the more expensive 4×4 AP over the less expensive 2×2 AP when the manufacturer has assured them that the 2×2 AP can manage high density installations and can offer the same throughput numbers to a 2×2 client.

I start seeking for scientific evidence to back up my argument that in real life scenarios, a 4×4 AP is superior to a 2×2. During my research, I stumbled across Wes Purvis’ outstanding talk from the 2018 WLPC in Phoenix. Wes went on to demonstrate that a 4×4 had a gain over a 3×3 AP of roughly 2.4dB on the downlink and 1dB on the uplink. In multi-client scenarios, this resulted in a 15% increase in data rate and a 10% increase in throughput.

I was content with what I had discovered up until this point, but not quite. After all, this demonstrates that a 4×4 is superior to a 3×3, but not superior to a 2×2. What if the odd number of antennas is to blame for the 3×3’s subpar performance? The question might seem absurd or strange to us wireless engineers, but it is an illustration of the kind of inquiry non-technical management might ask you in an effort to comprehend why you selected the more expensive 4×4 AP.

As a result, I carried out more research and discovered this fantastic Matlab work that described how to demonstrate the advantages of beam-forming from a 4×4 AP to a 2×2 client over using techniques such spatial expansion.
https://www.mathworks.com/help/wlan/ug/802-11ac-transmit-beamforming.html?fbclid=IwAR2ZBkgO_NV4Fz4e0-qwR7dmGusgv6fen9pRoLVnIQSbDpMx-rON799OOQo#responsive_offcanvas

I hypothesized that by just changing the number of transmitting antennas from 4 to 2, I could use the same illustration to demonstrate how beam-forming from a 4×4 AP to a 2×2 client is superior to beam-forming from a 2×2 AP to a 2×2 client. I executed the code twice under identical setup conditions, first for the case of 4×4=>2×2 and a second time for the case of 2×2=>2×2.

The setup evaluated a 2 spatial streams transmission using MCS4 on a 20MHz BW and TGac channel model with a Model-B delay profile from the AP to a client at a distance of 100 meters.

	4×4=>2×2 SS1	2×2=>2×2 SS1	4×4=>2×2 SS2	2×2=>2×2 SS2
EVM RMS	2.0%	4.7%	4.1%	8.4%
EVM dB	-33.9	-26.5	-27.7	-21.5

One can clearly see from the above results that the 4×4 AP had a lower EVM values than the 2×2 AP. This would lead to improved SNR values in real-world scenarios, which in turn would enable the 4×4 AP to shift gears and switch to a higher MCS rate.