NetFEC: In-network FEC Encoding Acceleration for Latency-sensitive Multimedia Applications

In face of packet loss, latency-sensitive multimedia applications cannot afford re-transmission because loss detection and re-transmission could lead to extra latency or otherwise compromised media quality. Alternatively, forward error correction (FEC) ensures reliability by adding redundancy and it is able to achieve lower latency at the cost of bandwidth and computational overheads. We propose to re-locate FEC encoding to hardware that better suits the computational pattern of FEC encoding than CPUs. In this paper, we present NetFEC, an in-network acceleration system that offloads the entire FEC encoding process on the emergent programmable switching ASICs, eliminating all CPU involvement. We design the ghost packet mechanism so that NetFEC can be compatible with important media transport functionalities, including congestion control, pacing and statistics. We integrate NetFEC with WebRTC and conduct extensive experiments with real hardwares. Our evaluations demonstrate that NetFEC is able to eliminate server CPU burden and adds negligible overheads.