On Mon, 24 Jun 2024 at 16:16, Robin Marx <[email protected]> wrote:

> 1. Just because a CDN supports HTTP/3 does not mean it enables it (by
> default) for all customers. For example, while Akamai (my current employer)
> provides support, it is explicitly opt-in instead of opt-out for existing
> customers, meaning we're probably at a much lower level of adoption than
> what's conceptually possible. I can't speak for other CDNs/large providers,
> but I imagine similar things happen there (e.g., only enable it by default
> for free/small customers, but require manual action from larger entities,
> which can be slow in the uptake).
>

You're right, and I suspect this is the single largest reason holding back
adoption.


> 2. Even if it's enabled, the alt-svc-based bootstrapping/discovery means
> you'll still have plenty of HTTP/2 by design. And while Chrome and Firefox
> pretty aggressively switch from H2 to H3 when discovered (even during a
> page load), Safari/Apple (at least for a long time, not 100% sure what they
> do not) kept using H2 for as long as possible, only switching to H3 when a
> new connection was really needed. This will (probably) be improved by HTTPS
> DNS records and alt-svc-bis, but those also have (current) deployment
> issues IIUC.
>

I can see how this is a bootstrapping issue. But surely 99% of content
fetches are towards a name that this user has visited before, so it *should*
be negligible. Perhaps there is an issue with how long browsers remember
Alt-svc or HTTPS information? Potentially this could be quite significant
too.


> 3. Even if the client tries HTTP/3, it will sometimes fail due to UDP rate
> limiting/blackholing/firewalling/flukes or things like MTU nasties that
> make HTTP/2 win the happy eyeballs race. I doubt this would contribute more
> than single-digit percentages to the overall number, but still a factor (I
> haven't seen recent numbers on this. Maybe Matt or Ian can comment, since
> they track more detailed client-side info?)
>

I'm also guessing this is single-digit percentages, but if data shows
otherwise then that would be something to work on.

On Mon, 24 Jun 2024 at 16:30, Daniel Stenberg <[email protected]> wrote:

>
> The ecosystem situation is not making it easy to use QUIC.
>

Thanks Daniel. You neatly summarise it in the blog: "curl’s situation is
symptomatic for a lot of other HTTP tools and libraries. HTTP/3 has been
and continues to be a much tougher deployment journey than HTTP/2 was."
Quite unfortunate that you have to poll OpenSSL due to an API shortcoming.


On Mon, 24 Jun 2024 at 17:14, Nick Banks <[email protected]> wrote:

> I've had https://github.com/microsoft/quicreach testing the top 5k
> hostnames for a few years now, and it provides this dashboard:
> https://microsoft.github.io/quicreach/. (Note, you can append ?count=2500
> to the URL to change the count of data points if you wish). While it's not
> a huge change, it shows about a steady 10+ increase every month (for at
> least the last year). We're almost at 1k hostnames supporting QUIC.
>

Thank Nick. I was initially puzzled how to interpret the data, but I see
this is out of the 5,021 top names listed in
https://github.com/microsoft/quicreach/blob/main/src/domains.hpp which is
taken from the Majestic Million. So I think it's saying 20% of those sites
have enabled H3 to their homepage. The growth shown in
https://microsoft.github.io/quicreach/?count=1500 is remarkably linear. If
this trend continues, we won't hit 50% until 2033.

Chris

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