Quals research talk: Packet Recovery as a Service

Abstract

We revisit a classic networking problem – how to recover from lost packets in the best-effort Internet. We propose ReWAN, a system that judiciously leverages the cloud to recover from lost or delayed packets with relatively low cost. ReWAN supplements and protects best-effort connections with proactive transmission of encoded packets along cloud paths at a low rate. The encoded packets take two forms: FEC encoding within a stream, and network coding across parallel streams sharing a pair of nearest-neighbor data centers. When receivers detect packet loss, they recover packets with the help of the nearby data center, not the sender, thus providing quick and reliable packet recovery for latency-sensitive applications. Using a prototype implementation and its deployment on the public cloud and the PlanetLab testbed, we quantify the benefits of ReWAN in providing fast, cost effective packet recovery. Using controlled experiments, we also explore how these benefits translate into improvements up and down the network stack. Scenarios we explore include improving user experience in video conferences over Skype, reducing worst-case latencies in short TCP transfers, and reducing loss in transmissions over cellular networks.