It was quite common for a re-sent packet to be dropped, and we saw several cases where the original packet and 4 or 5 re-sends of that packet would all be dropp

It was quite common for a re-sent packet to be dropped, and we saw several cases where the original packet and 4 or 5 re-sends of that packet would all be dropped. We were re-sending so many packets, we were starting to exceed the bandwidth of the modem, and then the latency would start to climb, and all hell would break loose. That is exactly why TCP has the "slow start" protocol. I am sympathetic to their problems, though. I understand that the implementations of TCP they had access to had way too much latency, and that back then, there probably wasn't much tuning one could do on the outside. What they did is a clever hack (message n has a copy of n-1) that takes advantage of the fact that they don't have to send much data in total.