Evaluating Flexicast QUIC through Real-World applications

Details

Supervisors

Bonaventure, Olivier

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] en sciences informatiques, à finalité spécialisée

Abstract

enMulticast is an efficient scheme for one-to-many communication, but widespread deployment on the Internet has long been slowed down by reliability and security, as well as pricing concerns leading to the chicken-or-the-egg problem. Flexicast QUIC (FCQUIC) addresses some of these issues by extending Multipath QUIC to allow a source to create a shared multicast flow along with per-client unicast paths, providing secure and reliable multicast to a modern transport protocol. In this thesis, we evaluate Flexicast QUIC through two contributions. We first implemented a multicast chat application using FCQUIC, and evaluated it against baselines built with QUIC and TCP (with and without TLS). The applications are evaluated on virtual network topologies of varying complexity, measuring end-to-end latency, source CPU utilization, and downstream goodput. FCQUIC's implementation overhead is measurable in small topologies, but is quickly absorbed by the multicast-induced latency gains as the number of receivers, message size, or network loss increases. We then address the acknowledgment implosion problem in Flexicast QUIC. We propose a hierarchical relay architecture in which relay nodes act as intermediate sources, redistributing data on new multicast flows, aggregating acknowledgments from downstream clients, and handling retransmissions locally. Two designs are presented, and one is implemented in two versions. We evaluate the relay implementations on Grid'5000 across 5 clusters, connected using GRE tunnels to create a multicast distribution tree on top of a non-multicast network. This is the first large-scale evaluation of Flexicast QUIC on real, geographically distributed servers rather than fully emulated topologies or smaller-scale deployments.