ECN is a far more efficient TCP congestion control mechanism that was incorporated in to the TCP standards in 2001 and it was meant to replace Jacobson's AIMD method.

[Navek]’s recent video goes over TCP congestion control, the solution to this problem which allows our much larger modern internet to work. In a 1987 paper, ...

With native TCP congestion control, a flow starts off in slow-start mode and increases the send rate until the full window size is reached or congestion is detected on the link.

Now when you check which congestion control algorithm is in use (with the command sysctl net.ipv4.tcp_congestion_control), you will see output containing bbr (Figure A). Figure A.