We've all heard much about QUIC in the past few years, and a lot has been made of its performance benefits for HTTP/3. For some of us however, HTTP/3 was always just the beginning, just the vehicle for us to get QUIC out into the world. This talk will go beyond these immediate benefits of QUIC and present my view on our somewhat anticipated sleight of hand. The talk will discuss QUIC's long-term value proposition for the Internet's architecture, including some recent projects and a broad sketch of where it can go.

In a typical CDN architecture the caching tier is fronted by a load-balancing tier; response content flows from the cache to the requester through the load-balancer. With this architecture extra I/O, CPU cycles and intra-cluster network bandwidth are spent to stream the content through multiple hops. We present a solution utilizing QUIC's properties to implement a form of Direct Server Return (DSR) from the caching layer, directly to the client. This form of DSR obviates the need for most intra-cluster communication when serving cached content. In this talk we go over the technical challenges in implementing QUIC cache DSR, its security properties, the expected performance improvements, and future applications.

Transfers in high-BDP links incur a startup delay for congestion control to probe the bandwidth of the underlying link. The impact of this delay is inversely proportional to the size of the transfer since small transfers may repeatedly spend all their transfer time probing for the available bandwidth and never reach it or utilize it. While this is necessary for links with rapidly changing capacity, it can be avoided in more predictable links such as backbone links. Existing TCP approaches are either limited to specific pairs of endpoints or require intermediate proxies. In this presentation, we share the approach we’ve developed for use with QUIC deployments in Meta’s backbone network. We use a modified congestion controller that tracks the average congestion control state for connections using each backbone path. This state is then used to “jumpstart” new connections across the same path, significantly reducing the startup delay. This, coupled with QUIC 0-rtt, offers significant savings compared to existing TCP-based approaches for transfers of size close to the path BDP. Screen reader support enabled.

LIVE Q&A featuring Jana Iyengar, Matt Joras, Yair Gottdenker & Joseph Beshay

Nestled between transport protocols (TCP, UDP, QUIC) and application protocols (HTTP, etc.) is a layer few are familiar with. Layer 4¾ sits hiding in plain sight, often only being glimpsed during curious events that raise its prominence, such as edge cases under scale of deployment or diverse usage. In this talk, we'll take a look at the Cloudflare Protocol's team view of the Internet edge and explore some of the fantastic cases we've seen, and what that might mean for future developments of Layer 4 and Layer 7 and the eponymous inbetween.

A key feature of HTTP/3 over QUIC is the ability to send a request in the first flight with the ClientHello. 0-RTT in IETF QUIC is notably more complex than gQUIC, with multiple packet number spaces and a limit on the amplification factor. Walk through some issues we hit and the tooling we used to identify and debug them before 0-RTT became a performance win for applications.

LIVE Q&A featuring Lucas Pardue & Ian Swett