L4S inches forward with Broadband Forum roadmap

The Broadband Forum has launched a hand-holding roadmap that promises to guide ISPs through the phased deployment of L4S, or Low Latency, Low Loss, Scalable Throughput – to give it its full title.

Used to mitigate congestion, L4S is a means of identifying data packets that get held up on their journey through a network, and then subsequently re-routing traffic to avoid the bottlenecks.

Adopted by the Internet Engineering Task Force (IETF), L4S has been around for five years, and has steadily risen to prominence as more industry players explore its potential uses.

Nokia and Vodafone showcased in April an end-to-end implementation of L4S on a passive optical network that reduced latency from 550 milliseconds to just 12. In February, Finland's Elisa – again with Nokia – incorporated L4S into a 5G Advanced demo.

Apple is also a fan of L4S, providing guidance to software developers about how to incorporate it into their apps.

It was originally developed to address latency issues specifically in cable infrastructure, and as such is also being put to use in low latency DOCSIS (LLD) networks.

It is evidently a fairly flexible solution then, and the Broadband Forum notes that L4S does not require end-to-end implementation across a whole network in order to start delivering results. Therefore its roadmap deliberately focuses on the parts of the network that stand to benefit the most.

"We're keenly aware that low and stable latency, along with high throughput, is fundamental to broadband performance for many interactive applications used in the home. This is especially true to ensure immersive experiences for applications like cloud gaming, and we're confident this project will help providers deliver new benefits to pass onto their customers," said Jonathan Newton, Vodafone distinguished technical expert and director of the Broadband Forum's access and transport architecture (ATA) work area.

"Broadband Forum is uniquely positioned to define how to implement L4S capability into a broadband network as a number of key congestion points are in our scope of work and we look forward to supporting the industry tackle a key pain-point for modern network applications."

In so doing, the Broadband Forum hopes to encourage service providers to get on and use L4S to tackle network bottlenecks.

"As trials and real-world implementations and deployments continue to ramp up in the likes of DOCSIS networks and a range of Apple operating software, Broadband Forum's new project will build on the IETF standard to ensure ultra-low latency can be ensured in broadband networks," said Craig Thomas, CEO at Broadband Forum. "In turn, software developers do not need to rewrite their own networking code to support L4S and application providers can continue to develop and introduce apps that require low latency in combination with high throughput."

With Wi-Fi 7 beginning to roll out to end users, and with L4S on the way, the future of home networking is beginning to look pretty rosy.

Earlier this year, Dell'Oro noted that 2024 will be the last year of declining revenue in the broadband access equipment market before a new spending-spree kicks in at the beginning of next year. It predicts that revenue for Wi-Fi 7 residential routers and broadband CPE with WLAN will reach $9.3 billion by 2028.

Hopefully by then, L4S will be a commercial reality.