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.<p>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.<p>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.<p>I really hope that something like Google's BBR will become the de-facto TCP congestion control algorithm in the end.