TCP's congestion control saved the internet
The fact that such a simple endpoint-only control loop (mostly) just works is one of the most amazing parts of the Internet to me.Still, it has its limits – the most obvious one to me is mentioned in the article: The optimal buffer size for each hop that TCP (or similarly flow-controlled traffic) traverses depends on the average delay and bandwidth, but these are per-flow quantities which an intermediate router can't properly estimate in principle.I've played around with Linux's excellent fq_codel a bit with promising results in the past, but ultimately, that's not a solution in the spirit of the Internet (dumb routers, smart endpoints) since it depends on looking at individual flows, something routers aren't really supposed to have to do.I really hope that something like Google's BBR will become the de-facto TCP congestion control algorithm in the end.