Nokia and Vodafone Conduct First Trial of L4S Technology

Nokia and Vodafone are collaborating to test the viability of L4S technology over passive optical networks (PON). It could greatly improve the experience of residential customers engaged in everyday internet activities like video conferencing and gaming.

Nokia’s research arm Nokia Bell Labs and Vodafone’s Fixed Access Center of Excellence recently performed the world’s first demonstration of L4S running over PON in Vodafone’s lab in Newbury, U.K. The demonstration was performed on an end-to-end fixed access network built with Nokia technology. It consisted of a broadband network gateway (BNG), a PON optical line terminal (OLT), multiple PON optical network terminals (ONTs), and WiFi access points. The tests showed extremely low and consistent end-to-end latencies when traveling across every element of the network.

Pioneered by Nokia Bell Labs, L4S stands for “Low Latency, Low Loss, and Scalable” throughput. It is an Internet Engineering Task Force (IETF) standard technology that tackles a significant source of peak latency on the Internet: queuing delays. Queuing delay happens when packets wait idly in buffers across the network, for instance in routers and modems, before being forwarded. L4S consistently achieves near-zero packet queuing delay, no matter how much load the network experiences. By eliminating queuing delays, L4S removes big variations in latency without compromising network speeds. In the lab tests, Vodafone and Nokia Bell Labs measured consistent latencies of 1.05ms at local Ethernet ports running over a fully congested access network (BNG to ONT), and just 12.1ms when including a fully congested WiFi link as the final connection.

While the Vodafone and Nokia Bell Labs tests were conducted using PON networks, L4S can be implemented over any access technology, wireless or wireline, and applied to any latency-dependent application. In November, Nokia Bell Labs and Hololight, a leading innovator in enterprise XR solutions, created a proof of concept demonstrating how L4S could support multiple simultaneous XR users over the same wireless connection without sacrificing performance. L4S is an example of the network-application symbiosis that is a key component of UNEXT, a new Nokia Bell Labs research initiative. UNEXT will transform the network into a self-managing, interactive operating system that will break down barriers that have traditionally prevented network elements from interoperating.