Roaming might seem like a trivial concern—just a WiFi hiccup as you move from one access point (AP) to another. However, in the bustling industrial networks, it’s a heavyweight issue, often tipping the scales towards unreliability and downtime. As Industry 4.0 dictates high mobility, the sting of average latency – not even the peak latency – can halt production and hamper efficiency. Let’s talk about traditional solutions like Fast Roaming and how they are often caught flat-footed in these high-stakes environments, and explore whether Mesh technologies can be a better solution to carry the load.
Hitchhiker’s Guide to WiFi Fast Roaming
Labeling it Fast Roaming might sound like a sleek upgrade from the standard WiFi package, but it’s really a blend of the protocols 802.11r, 11k, and 11v. Our starting point in this article is about what happens under the hood of standard WiFi, in a world without Fast roaming.
World without Fast Roaming
A mobile robot in an industrial environment is meant to perform its tasks while tethered invisibly to a WiFi AP. As it moves, its connection to the current AP starts to wane – signal strength twinkling like a distant star. Eventually, the inevitable happens:
- The device disconnects, causing the robot to come to an abrupt stop.
- It then scans the surroundings, searching for the strongest available AP beacon.
- Once chosen, the device sends a request to connect to this new beacon.
- A security handshake ensues, validating credentials and ensuring a secure link.
- Connection is re-established, the robot resumes its journey, all with a few seconds of downtime.
Rinse and repeat this process, and you have the cumbersome, stutter-step traditional WiFi roaming. But, we shouldn’t dwell in a world without fast solutions. Instead, let’s explore the advanced trio of 802.11r, 11k, and 11v – what are these, and how do they aim to smooth out the moving machine’s journey? Do they succeed?
Fast roaming in WiFi
Enter fast roaming, or better yet… 802.11k, 802.11v, and 802.11r. These WiFi amendments work in tandem, supported by some APs and client devices, to enhance roaming performance. But what are these standards, and how do they improve the roaming experience? Let’s break them down.
802.11k – Radio Resource Measurement
This amendment empowers wireless clients to request detailed information about the network environment from APs. By having this information, the client can make more informed decisions about when and where to roam, thus optimizing the roaming process and reducing the time spent scanning for suitable APs. This data includes crucial details about neighboring APs, such as their signal strength, channel utilization, and even insights into the AP’s capabilities or load.
📱For instance, as a user moves through an office space with their smartphone, the device continuously evaluates the wireless environment and prepares for a potential switch to an AP with more favorable conditions.
802.11v – Wireless Network Management
This standard allows APs to provide clients with comprehensive information about the network topology, which includes suggestions on potential target APs for optimal roaming. It also enables APs to steer or guide client devices in making more effective roaming decisions, which can significantly enhance the management of client distribution across the network and minimize frequency congestion. 802.11v employs APs to empower the network to manage client devices more proactively. It involves sending specific suggestions or commands to clients about which AP to connect to next, directing them towards less congested APs or those that offer better service.
Furthermore, 802.11v can effectively manage the timing of a client’s roaming, suggesting when it might be optimal to switch APs. This assists in load balancing across the network, beneficial for network stability.
📱Returning to the smartphone example:
Through 802.11v capabilities, the current AP might suggest the smartphone to prepare to roam to a specific AP that has optimal conditions, such as lower load and stronger signal. Additionally, 802.11v enables the AP to transmit a BSS Transition Management Request (BSS), informing the device that it should move to a better-suited AP. This not only balances the network load but also optimizes overall network performance by maintaining a strong and reliable connection throughout its mobility.
802.11r: Fast Transition (FT)
The primary aim of 802.11r is to accelerate the authentication process when hopping from one AP to another. Standard Wi-Fi protocols can make re-authentication a lengthy ordeal, but 802.11r slashes this overhead by enabling some simplified authentication steps.
802.11r introduces two specific methods for clients to roam between APs:
- Over-the-Air Fast BSS Transition: This method enables direct re-authentication communication between the client and the target AP. Previously established shared key is used, significantly speeding up the process.
- Over-the-DS Fast BSS Transition: This method leverages the backend infrastructure, such as a wired network, to facilitate the re-authentication process. The client communicates with the current AP. It then coordinates with the target AP through the network’s backend to manage the authentication credentials.
📱Now, let’s extend the scenario with the smartphone:
- 802.11v – Initial Connection: Upon entering the office, the user’s smartphone connects to Wi-Fi. Then, it goes through a full authentication process with an AP. This setup establishes credentials and prepares for potential fast transitions by pre-authenticating with neighboring APs.
- Moving across the office: When moving beyond the range of the initial AP, the smartphone uses data from 802.11k. The goal is to evaluate the new APs with best potential. It considers factors like signal strength and load. With 802.11v, the network might suggest or even direct the device to transition to a specific AP, predicted to offer better network service.
- Engaging 802.11r for Fast Roaming: When the smartphone either decides or is instructed to switch to a new AP, 802.11r’s fast transition capabilities spring into action. If the smartphone and the target AP have pre-authenticated during the initial connection, they can swiftly re-establish a secure connection using the previously shared key. This drastically cuts down the time typically needed for re-authentication. As a result, the smartphone switches to the new AP. There is minimal connectivity disruption, even not noticeable, maintaining a seamless experience while moving through the office.
Heads up – not all three come together as a rule
It’s important to note that not all three standards are always implemented together. Depending on the vendor, some systems may support only two or even just one of these technologies. Users are encouraged to consult their device manuals or vendor specifications to understand what is specifically meant by fast roaming in their equipment.
Limitations of traditional Fast roaming techniques
While traditional Fast roaming techniques such as 802.11r, 802.11k, and 802.11v have improved user experience by reducing the time devices take to switch between APs, they don’t come without drawbacks. These protocols operate on a “make quickly after break” basis. What this means is that they terminate the connection with the current AP before establishing a new one.
Industry 4.0 applications, including robots, drones, autonomous vehicles, and more, simply don’t have the time. They are required to move swiftly, seamlessly, and to reliably complete their tasks. If they have to wait for a new connection each time they move (and they move a lot), it’s hard to expect them to do what they were made to do. Fast roaming is faster than standard Wi-Fi roaming. However, it still involves a brief disconnection which can be problematic in such scenarios that require uninterrupted connectivity.
Challenges in industrial environments
- Momentary disconnects: Even short lapses in connectivity can cause significant disruptions in industrial settings. Operations such as remote control, real-time monitoring of critical infrastructure, or automated manufacturing processes require continuous data flow without interruptions.
- High-density areas: In environments where many devices compete for bandwidth, traditional roaming protocols can falter, leading to delays and potential packet loss. This competition can strain the network, impacting both connection stability and roaming efficiency.
- Complex physical layouts: The intricate physical structures of industrial environments can impede wireless signals. Fast roaming protocols might not effectively navigate obstacles such as walls, metallic structures, or liquids. These can result in weaker connections or longer times spent searching for optimal signal paths.
- Reactive mechanisms: The mentioned Fast roaming technology primarily reacts to connectivity changes rather than anticipating them. This reactive nature may not suffice in high-stakes environments where decision-making takes split milliseconds.
Introducing Meshmerize and proactive “Make before break” link creation
Meshmerize offers a novel approach to network connectivity. Particularly, it shines in demanding industrial environments where traditional Fast roaming solutions fall short. Unlike standard methods that cater well to mobile phones and laptops, industrial applications require a more robust solution. This is where Meshmerize’s proactive “Make before break” link creation comes into play.
Our advanced connectivity model incorporates redundant multipath roaming, which allows devices to seamlessly switch between multiple network paths without losing connection. By using multiple paths simultaneously, Meshmerize ensures that even if one path deteriorates or fails, others are already active and capable of carrying the load without any interruption to the data flow. To learn more about how Meshmerize smartly optimizes this process, we are inviting you to dig deeper into our blog post about the Meshmerize multipath routing protocol.
Beyond Fast roaming: Meshmerize proactive connectivity in industrial networks
Roaming might seem like a trivial concern – merely a WiFi hiccup. However, in industrial networks, it emerges as a critical issue. Traditional solutions like Fast Roaming use a “make quickly after break” approach and often struggle in high-stakes environments. Meshmerize stands out by proactively creating “Make Before Break” links. This method doesn’t just react to changes – it anticipates them.
As Industry 4.0 propels us toward more interconnected and automated environments, the demand for cutting-edge connectivity solutions becomes increasingly critical. Just as outdated hardware cannot sustain new industrial requirements, traditional connectivity methods are not equipped to handle the unique challenges of these dynamic settings. This is where a solution like Meshmerize becomes indispensable. We are inviting you to explore the rich feature set offered by Meshmerize and see how it can transform the industrial connectivity landscape.
Having questions? Let us address them as well. You are welcome to contact us, our team would be glad to assist you.
Meshmerize is a startup based in Dresden, Germany that provides the ultimate mesh network software to an array of industries. The full potential of Meshmerize is yet to be seen. We would like to hear your thoughts – let us know what you think at hello@meshmerize.net
