X-Plane: A High-Throughput Large-Capacity 5G UPF

Cloud providers, such as AWS and Azure, have started providing 5G services on their cloud infrastructure. In this paper, we present the design and implementation of X-Plane, a system that uses commercial programmable ASICs and DRAM servers on today's cloud infrastructure to implement high-performance 5G User Plane Function (UPF). Building X-Plane is hard because we need to address the following challenges: consistency issues when concurrently accessing UPF state data, slow UE table lookup due to repetitive and numerous Packet Detection Rule (PDR) matching, and the need to handle out-of-order packets from disconnected UEs. X-Plane addresses these challenges by designing three novel technologies: concurrent state data access protocol, fast flow table and paging buffer for handling out-of-order packets. We demonstrate its feasibility and practicality with our implementation on a Tofino-based programmable ASIC. Our evaluation shows that X-Plane can support over 490Gbps throughput per ASIC pipeline, over 10 million UEs, and finish packet processing within predictable 4 us on average.