Thread by @danielbryantuk

What is HTTP/3 and why should you care? 🤔

- Reduced latency and buffering
- 70%+ browser support
- Benefits for machines with old OS/kernels

My team and I have been chatting to experts and playing with the latest version of the protocol that powers the web

Read on 🧵 👇

HTTP/3 is supported by 70%+ of browsers (including Chrome, Firefox, and Edge), and according to W3Techs 25% of the top 10 million websites 🌐

The official RFC/spec was standardized in June 2022:

datatracker.ietf.org/doc/rfc9114/

I recently had a fascinating @ambassdorlabs podcast chat with @alyssa_oss, Senior Staff Engineer at Google and @EnvoyProxy committer 🙌

We covered a lot of ground in 20 minutes: HTTP/3 Use Cases, Envoy Support, and Google’s Rollout

getambassador.io/kubernetes-tho…

@alyssa_oss @EnvoyProxy Key takeaways from my HTTP/3 chat with @alyssa_oss

ℹ️ Two big wins in HTTP/3 are the zero roundtrip handshake and improved congestion control
ℹ️ As HTTP/3 is implemented in userspace, you get these performance benefits even if you haven’t updated (or can’t update) your OS kernel

@alyssa_oss @EnvoyProxy ℹ️ End users who see even more benefit are those on lossier networks (e.g., emerging markets, mobile, IoT use cases)
ℹ️ Adding HTTP/3 support to a proxy, ingress, or API gateway is non-trivial (unlike HTTP/2) due to sophisticated congestion control and cryptography

@alyssa_oss @EnvoyProxy If you want to understand the inner workings of HTTP/3 (and changes from HTTP/2), check out the Wikipedia page:

en.wikipedia.org/wiki/HTTP/3

This image from the page shows the main differences in the stack:

@alyssa_oss @EnvoyProxy ℹ️ HTTP/2 sped up HTTP/1 dramatically – but if you lose one packet on a connection, everything gets stalled until the packet is retransmitted.
ℹ️ This is a fundamental limitation of TCP, so HTTP/3 speeds up HTTP/2 even more by implementing the protocol on top of UDP.

@alyssa_oss @EnvoyProxy This video with @OptimisticRyan and @alyssa_oss from the #KubeCon NA 2021 event is also super useful for understanding the changes, benefits, and challenges of HTTP/3 (and has an animation showing head-of-line blocking! 🚅 🚅 🚅 )

@alyssa_oss @EnvoyProxy @OptimisticRyan My team and I have summarised the key info on HTTP/3 on this page: 📝

getambassador.io/kubernetes-lea…

Please let us know if you would like more information to be added here!

@alyssa_oss @EnvoyProxy @OptimisticRyan If you want to experiment with HTTP/3, check out this blog from my colleague, Tenshin Higashi 🧰

He walks through configuring the @CloudNativeFdn Emissary-ingress and Edge Stack API gateways for HTTP/3 support (these projects are built upon @EnvoyProxy)

blog.getambassador.io/how-to-impleme…

@alyssa_oss @EnvoyProxy @OptimisticRyan @CloudNativeFdn If you prefer a live and interactive walkthrough, Tenshin is also running a workshop on July 13th, 12 pm EDT / 5 pm BST / 9:30 pm IST 🤝

getambassador.io/implementing-h…

@alyssa_oss @EnvoyProxy @OptimisticRyan @CloudNativeFdn Thanks for reading and let me know if you have any questions! 🙏