Late with a reply, but want to note that this is not true. Most OSes scale tcp congestion control windows (snd_cwnd) based on the target IP, that is any increas

Late with a reply, but want to note that this is not true. Most OSes scale tcp congestion control windows (snd_cwnd) based on the target IP, that is any increase of the window in any tcp connection to the same host increases the window for all open connections. Even if you close all connections, the kernel caches the last known window size for this host and re-uses this on subsequent connections for a given timeframe.