Interestingly, this is still relevant today when doing large data transfers between hosts with long RTTs using TCP: the typical TCP congestion control implementations (i.e. bic (http://en.wikipedia.org/wiki/BIC_TCP)) use ACKs to update their window size (which come back one RTT later) and hence their windows grow much slower than two hosts with the same capacity but a smaller RTT.

Cubic (http://en.wikipedia.org/wiki/CUBIC_TCP) and htcp (http://smakd.potaroo.net/ietf/all-ids/draft-leith-tcp-htcp-0...) are two congestion control methods which avoid this by not increasing the congestion window size by a function of the RTT (and are recommended if doing large data transfers across high capacity links with high RTT). In linux you can typically check your TCP congestion control algorithm by: "sysctl net.ipv4.tcp_congestion_control".