The Wireless Broadband Alliance (WBA) released a set of “L4S Implementation Guidelines” for low latency, low loss and scalable (L4S) throughput over Wi-Fi networks. The guidelines demonstrate how demand for low latency Wi-Fi applications such as cloud gaming, augmented reality (AR) and virtual reality (VR) can be achieved with an explanation of implementation approaches, Access Point (AP) tests and simulation studies for L4S AP performance in different scenarios.

Demand for L4S applications is growing, with both telecoms organisations and developers beginning to implement the technology. Apple, for example, provides guidance to developers on how to implement L4S in their apps, in 2024 Nokia and Vodafone conducted the first trial of L4S over an end-to-end passive optical network, reducing latency from 550 milliseconds to 12 milliseconds, demonstrating its suitability for real-time applications, and Comcast recently announced deployment of L4S technology, which will be rolling out across its entire footprint.

Business Impact of L4S

Buffering is a primary source of delay in both wired and wireless networks, occurring when incoming packets exceed the departure rate, leading to high buffer occupancy. Latency in Wi-Fi networks is largely influenced by two factors: delays associated with queuing and buffering under load, and delays introduced by the 802.11 Media Access Control protocol.

The adoption of L4S technology is set to revolutionize Wi-Fi performance, particularly for applications that demand low latency and high throughput. To address these issues, the L4S project aims to minimize buffering delays, reduce data loss, and enable scalable throughput. This will enable several business benefits for vendors, enterprises, and customers:

• Supporting Next-Gen Applications – The technology enables enterprises and service providers to meet the growing demand for high-bandwidth, low latency services and enhance operational efficiency for modern, high performance applications.
• Enhanced Customer Satisfaction and Revenue Potential – Industries such as gaming, media streaming and telemedicine will achieve superior network performance, boosting customer retention and unlocking new revenue opportunities.
• WBA’s Industry Leadership – The WBA is fostering collaboration across the industry, driving the adoption of L4S technology, and positioning Wi-Fi as a critical enabler for emerging applications.

L4S technology enables vendors and enterprises to achieve new business benefits and success with their applications through four key technical benefits, all of which are discussed in more detail within the implementation guide.

• Revolutionizing Wi-Fi Performance – L4S tackles latency and congestion issues, offering groundbreaking solutions for applications like cloud gaming, AR/VR, and video conferencing.
• Significant Reduction in Latency – utilizing explicit congestion notification in IP headers and active queue management (AQM), L4S significantly reduces average and tail buffering delays by more than 90 percent, enhancing real-time application performance.
• Improved Throughput and Stability – L4S provides smoother and more stable throughput, minimizing network congestion and packet loss for consistent high performance connectivity. Stable throughput also enables more efficient packet scheduling techniques to be used for optimizing Wi-Fi network performance.
• Future-Proofing Wi-Fi Networks – Through the WBAs development and standardization of L4S technology, Wi-Fi networks are prepared to handle future challenges, ensuring long-term performance and scalability.

The L4S Implementation Guidelines

The WBA has developed the L4S Implementation Guidelines to assist industry stakeholders in implementing L4S technology, the guidelines cover:

• An overview of L4S technology, what it is, and how it works
• Why support for L4S in Wi-Fi equipment is critical for end-to-end application performance
• How Wi-Fi equipment suppliers can implement L4S support in their products
• Simulation and test results that illustrate the benefit of L4S
• Initial results on optimizing enhanced distributed channel access parameters.

In 2025, the WBA will continue advancing L4S in coordination with QoS Management initiatives, including additional trials, report generation, provider surveys and evolving L4S testing scenarios.

Tiago Rodrigues, president and CEO of the WBA, said, “As L4S technology continues to evolve and gain traction, it will play a pivotal role in shaping the future of Wi-Fi networks, ensuring they meet the demands of modern, latency-sensitive applications. The L4S Implementation Guide will help vendors and enterprises to achieve maximum business impact from the technology and improve customer experiences for latency-sensitive applications such as gaming and VR.”

Metin Taskin, CEO and founder of Airties, said, “At Airties, our aim is to help improve the home connectivity experience for ISPs, including latency, to help increase customer satisfaction, reduce churn and attract new customers. Speed alone is no longer a competitive advantage for broadband operators since many interactive applications rely as much on low latency as speed. ISPs need solutions like L4S, coupled with the right software management tools, to improve QoE, and we’re very proud to work with WBA to help lead the way on this important industry initiative.”

Greg White, distinguished technologist at CableLabs, said, “As network operators shift from a mindset focused on speed alone as the key indicator of network quality, to one where user-experience and adaptability are front of mind, L4S will be a critical technology that will enable Wi-Fi networks to meet the needs and expectations of users, both for today’s applications and for future applications that aren’t possible today.”

Lili Hervieu, principal architect at CableLabs, stated, “L4S is a key technology for efficiently reducing buffer delays and supporting end-to-end low latency by enabling fine-grain coordination between the network and application sender. With a significant share of internet traffic relying on Wi-Fi, integrating L4S over Wi-Fi is essential. These guidelines offer key insights into L4S deployment over Wi-Fi supported by extensive field tests and simulations.”

Dr. Necati Canpolat, senior staff wireless architect at Intel and WBA board director, concluded, “Intel is proud to be leading this initiative at the WBA. Through our leadership roles at IEEE, WFA, and WBA, and with its product support, Intel has been at the forefront of addressing Wi-Fi latency issues. L4S offers additional mechanisms for improving end-to-end latency and connectivity experiences.”