Does changing TCP congestion control algorithm system wide in linux affect already established connections?

Question

If I change system wide TCP congestion control algorithm as shown below, does it affect already established connections also ? Is there any adverse impact on them or it occurs seamlessly ?

# echo reno > /proc/sys/net/ipv4/tcp_congestion_control

Answer 1

The answer is "NO". Changing the congestion algorithm at run time do not effect already established connections.

I have tested changing and selecting the best congestion algorithm for our infrastructure.

The reason is that changing the algorithm will only effect the handling of current traffic, and after changing the packets handling will be based on the algorithm you selected.