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Comment by cryptonector | Hacker News Reader

HTTP/2 and HTTP/3 do not change the semantics of HTTP. That means you can run reverse proxies to server HTTP/1 services as /2 and/or /3 and vice-versa. As a result the transition will be a lot easier than the transition to IPv6. I expect that the transition in corporate networks will be faster -- the opposite of the IPv6 case -- because there is a lot of appeal to HTTP/3.

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> because there is a lot of appeal to HTTP/3

I thought the primary appeal of HTTP/3 is for mobile clients, and bad connections in general, because it circumvents TCP head of line blocking and connections can persist across networks.

That doesn't feel terribly relevant in corporate networks.

(not disputing that it's not comparable to the v6 transition)

His claim of corporate appeal is completely unsubstantiated and I think when he says corporate he isn't referring to enterprise.

Enterprises largely won't give two shits about HTTP/3.

Just last week I took ownership of another department's decade old app written in VB.NET WinForms. The former dev team was putting the finishing touches on the C# WebForms refactor. It's been interesting taking a step back in time to Dev practices from 2008.

The appeal of H3 is smaller memory footprint.

The transition will be faster because of that a big chunck of the internet is gatewayed through a few big players (e.g. Cloudflare, AWS, CDNs, the new wave of static deployment services like Netlify and Zeit.co, big websites like google, facebook, netflix, etc...)

You realize that HTTP/2 is still nowhere near to being adopted by corporations? It's really far fetched to plan HTTP/3 and expect any adoption.

Most _domains_ may not support HTTP/3, but I fully expect that within a few years most _traffic_ will be HTTP/3.

Qualys' "SSL Pulse" says 47.1% of surveyed sites offered HTTP/2 and about 30% of surveyed sites offer TLS 1.3

Increasingly "corporations" out-source this problem to specialists who are only too pleased to use newer technologies with better performance and collect the same money.

Because 47% of sites run on Cloudflare or similar CDN that started enabling HTTP/2 for non-paying customers.

The application servers running the site do not accept HTTP/2 and most likely can't support it at all (we're a python shop and none of the web frameworks we use could do HTTP/2 when we looked into it).

But exactly that's the point. It can be handled transparently in a much easier way then the Ipv6 switch. (Because IPv6 is so much more different then just IPv4 + more addresses, and worse, many people don't realize it and treat it as IPv4 with more addresses which resulted in many problems).

For HTTP/2 at least, I think the main benefit in terms of performance applies to the "last hop", so you still get a more reliable experience even if the connection between the CDN/proxy and app server is http/1.1

True, through many web-sites don't have to care about the performance difference.

But for companies like CloudFlare or Googl HTTP/2 means less traffic overhead (multiplexing+header compression) and can save them a lot of bandwidth (aka. money) with that.

Exactly. AWS and GCP load balancers accept HTTP/2 but allow for those requests to be forward to backend instances as HTTP/1 because of this.

In fact AWS ALB does not even support HTTP/2 on the backends which is really annoying.

The fact that UDP involves much smaller PCBs than TCP alone will drive adoption of HTTP/3 because it will free up a fair bit of memory.

More availability of HTTP version gateways in load balancers and other reverse proxies is all that's needed, and that's coming along.

Protocol Control Block for anyone else wondering https://www.oreilly.com/library/view/tcpip-illustrated/02016...

You still need to keep your unacknowledged data buffered somewhere. If the kernel isn't holding it then it's in userspace.

More specifically no PCB, for UDP itself.

It's not nil. For "connected" UDP sockets, it's smaller than TCP's, but not nil because, well, buffers. And for non-connected UDP sockets there's still buffers. The main thing is that you can have much less buffer space because you might always be willing to drop packets. Ultimately you can have much lower memory pressure from those buffers and the smaller PCBs.

This is only mostly true, they do subtly change some semantics.

As a motivational example, it is possible to encode a colon in a header name in http2 but not in http1.1, and this does not violate the RFC which only blacklists "\0\r\n".

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