Low-Variance Latency Through Forward Error Correction on Wide-Area Networks

High bandwidth-delay product (BDP) networks present many performance challenges. We present the design, implementation, and evaluation of UDT+FEC, a software system that provides high throughput, low latency, and low-variance latency on wide-area networks (WAN), especially for large data transfers. Using 2D-XOR forward error correction (FEC), implemented as an extension of the UDP-based Data Transfer (UDT) system, we show that it is possible to match the throughput and latency of other state-of-the-art tools, but also provide the added property of lower variance in the interarrival times of messages at the receiver. With a variety of macro- and micro-benchmarks, we quantify the relative advantages of UDT+FEC, when compared to using GridFTP combined with CUBIC, BBR, and parallel streams.We find that UDT+FEC has substantially lower variance in the latency of message arrivals (approximated by message interarrival times, for one-way transmissions) when compared to different combinations of CUBIC, BBR, and parallel streams.