[ih] Why did DCCP fail to gain traction?

[John R. Levine]

On Sun, 4 Oct 2026, Dave Crocker wrote:
> On 10/3/2026 5:56 PM, John Levine via Internet-history wrote:
>> HTTP version 1 and 2 ran over TCP, http/3 runs over
>> QUIC which is built on UDP so it doesn't need kernel support, with all
>> the multiplexing and flow control in the application

> Why can't TCP run in the application?
> What does it require that UDP+QUIC don't also require?

Nothing, give or take some way to route the individual protocol 6 packets 
to the application.  If TCP weren't already in every operating system for 
historical reasons, I suspect we'd have a QUIC-lite for applications where 
a single stream is adequate.

I see that there is a kernel implementation of QUIC for linux that might 
be faster and makes it easier to integrate into SMB an NFS which are also 
in the kernel.  It doesn't seem to be much faster than the user library 
version.

For client systems, speed isn't very important since the machines that web 
browsers run on are rarely CPU bound. High volume servers like Google's 
run on highly customized hardware and software so I suppose if there were 
a benefit to putting QUIC in the kernel on those systems, they'd just do 
it.

R's,
John