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Comment by fragmede | Hacker News Reader

What is QUIC in your book?

Given, say, $50 million of dev time, what would you go about fixing? And in what way?

In addition to QUIC, KCP [1] is another reliable low-latency protocol that sits on top of UDP that might be interesting. And unlike RFC 9000/9001 (QUIC), encryption is optional. I haven't really seen it mentioned much outside of primarily China-focused projects, like V2Ray [2], but there is also some English information in their Git repo [2].

[1]: <https://github.com/skywind3000/kcp>

[2]: <https://www.v2fly.org/en_US/>

[3]: <https://github.com/skywind3000/kcp/blob/master/README.en.md>

KCP uses a brute force congestion control algorithm that is unfair and inefficient. It is also poorly specified, which is probably why it is less commonly used outside circumvention circles.

KCP is notably used by the popular mobile game Genshin Impact.

Still is looks interesting for some use cases, even though it's not fair if it's fully utilized on the internet.

IMHO QUIC is nice, but a disappointment, since it could have been so much more.

Does not handle unreliable messages, still only (multi)streaming, no direct support for multicast, 0-rtt which need a lot of stuff to be manually done TheRightWay or risk amplification attacks, the (imho) under-researched (and removed) forward error correction, and more.

I just restarted working on what I consider to be the solution to this, federated authentication and a bit more, but $50M is too far to be even a dream since I am not google.

Doesn't QUIC still run over TCP? I thought it was a replacement for HTTP not TCP (Edit: looks like it replaces TCP and HTTP)

QUIC runs over UDP, and provides streams and encryption. HTTP/3 is designed to take advantage of QUIC streams (replacing HTTP/2 streams which were problematic due to TCP head of line blocking).

The RFCs are a bit elaborate so folks interested might want to look at this instead[1], which has one of the RFC authors explaining the basics of QUIC and HTTP/3.

[1] https://www.youtube.com/watch?v=cdb7M37o9sU

It replaces TCP+TLS, and runs multiple streams on the same conn, supports transition from eg wifi to ethernet on at least one of the nodes. And since it's over udp implementations are mostly in user space. Which is good if you want it now, but not great for performance. Ip packets are very small so you gotta have either kernel support for quic or batch IO, otherwise it's often CPU limited (yes, really). In addition congestion control is wonky, unfortunately. In my experience (quic-go), it's too shy in the presence of TCP streams, which ends up getting more bandwidth. But that depends on the algorithm used, implementation and God knows what else.

I guess you were thinking about another clever name protocol, SPDY :-)

SPDY → HTTP/2

QUIC → HTTP/3

Nope, UDP.

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