Broadband Forum Push Home ISPs to Adopt Low Latency L4S Technology

The Broadband Forum has launched a new roadmap that they hope will aid ISPs in implementing the new Low Latency, Low Loss and Scalable Throughput (L4S) technology, which has the potential to improve network latency times for popular UK internet activities like online video games, video conferencing, cloud gaming and so forth.

Network latency is a measure of the time that it takes for a packet of data to travel from your computer to a remote server and then back again (ping). The delay is measured in milliseconds, and modern broadband connections will often have an average latency of anything from around c.4ms to 40ms (what is normal for your connection will depend on lots of different factors).

The shortest time is always best for latency, although the times can be affected by various things, such as the performance of remote internet servers, the connection technology being used, network congestion, peering / routing problems and the setup of your own home network etc. But consumers with Fibre-to-the-Premises (FTTP) connections can usually expect some of the best latency times of c.2-10ms.

However, there’s always room for improvement, which is why L4S is now being given more of a push. The new technology is based on the knowledge that the root cause of queuing delay (i.e. when packets wait idly in buffers across the network, for instance in routers and modems, before being forwarded) is in the capacity-seeking congestion controllers of senders, not in the queue itself.

L4S attempts to move away from the congestion control algorithms that sometimes cause substantial queuing delay and instead adopt a new class of congestion controls, which seek capacity with very little queuing. The new technology introduces immediate congestion feedback from network bottlenecks as soon as data packets begin to queue, which when combined with a scalable congestion control scheme on the sending hosts can result in lower latency.

Companies and operators like Vodafone, Apple, Nokia and Intel have been increasingly pushing for wider adoption of L4S since it was specified by the Internet Engineering Task Force (IETF) last year. The Broadband Forum is now establishing a roadmap to help show operators and service providers how to implement L4S.

As L4S does not require implementation across the whole network to start to deliver benefits, Broadband Forum’s project will support phased implementations of the technology that focus on the most beneficial parts of the network first, on the journey to a full end-to-end support.

Jonathan Newton, Vodafone and Access and Transport Architecture Work Area Director at Broadband Forum, said:

“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.

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.”

One key factor in all this is that L4S is good at handling latency in a more congested network environment, which is important because network congestion often results in rising levels of packet loss and slower latency times (e.g. video games often experience this as lag in online multiplayer games). But by tackling the causes of this issue, end-users are more likely to enjoy a smoother experience.

At present this is mostly being implemented alongside more modern FTTP broadband and 5G mobile networks, although it’s still a fairly new technology and so hasn’t yet been widely adopted.