Evaluating the L4S Architecture in Cellular Networks with a Programmable Switch

Low-Iatency applications, such as cloud gaming or cloud robotics are very demanding in terms of network latency. The IETF defines the L4S (Low Latency Low Loss Scalable throughput) architecture, to enable the delivery of high-bitrate low-latency applications without degrading the quality of other services. To deploy and upgrade L4S in network equipment to follow the transport protocols entering an age of quick evolutions, P4 (Programming Protocol-Independent Packet Processor), a programmable data plane concept, can help since it facilitates the deployment of networking software. In this paper, we propose a P4-based L4S solution and the performed evaluation proves our system behaves as expected. Furthermore, to be largely deployed, L4S should also be efficient under real cellular network conditions, which can vary over time and where the main network bottlenecks are. However, our evaluation shows limitations of L4S in providing high throughput while ensuring low latency delivery with time varying network conditions.