Improving the Efficiency and Flexibility of Network Communications
PhD Thesis · 2026
Abstract
Modern networks are provisioned for peak load rather than average load, and this gap is largely driven by one-to-many events — live streaming, software updates, popular game releases — where many receivers request the same content at nearly the same time. This thesis improves the efficiency of these networks by reconsidering the use of multicast to reduce peak traffic.
We first leverage the spare bandwidth left by over-provisioning to reduce latency, transparently protecting traffic with Forward Erasure Correction within a network-layer tunnel, without requiring end hosts to implement the mechanism.
The core of this thesis reconsiders multicast itself. Building on QUIC and its multipath extension, we design Flexicast QUIC, combining shared multicast delivery with per-receiver unicast paths within a single connection: receivers fall back to unicast whenever multicast underperforms, turning multicast into an optimization rather than an all-or-nothing choice. Knowing the exact set of active receivers also lets us revisit the classic acknowledgment-implosion problem and pace feedback to keep Flexicast QUIC scalable as the group grows.
Finally, we analyze the optimistic acknowledgment attack in QUIC, showing that numerous implementations were exposed to it despite an optional protection in the specification — leading several widely deployed implementations to adopt it.
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Cite (BibTeX)
@phdthesis{navarre2026improving,
title={Improving the Efficiency and Flexibility of Network Communications},
author={Navarre, Louis},
year={2026},
school={UCLouvain}
}