Nokia and Vodafone are testing the viability of L4S technology over passive optical networks (PON).
L4S is an acronym for “Low Latency, Low Loss, and Scalable” throughput, a technology standardized by the Internet Engineering Task Force (IETF). It addresses a major cause of high peak latency on the Internet, namely, queuing delays. These delays occur as packets linger in network buffers, such as those in routers and modems, waiting to be sent on.
The L4S networking approach reliably maintains packet queuing delay at almost zero, regardless of the network’s load.
The first demonstration of L4S running over PON occurred 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 travelling across every element of the network.
In the lab tests, Vodafone and Nokia Bell Labs measured consistent1 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.
Azimeh Sefidcon, Head of Network Systems and Security Research, Bell Labs at Nokia, said: “These highly encouraging results show L4S will unshackle any real-time application that would normally be constrained by high latency. Videoconferencing, cloud-gaming, augmented reality and even the remote operations of drones would run flawlessly across the internet, without experiencing any significant queuing delays.”
