1500 Archers on a 28.8: Network Programming in Age of Empires and Beyond

One neat hack I read about, I think from a later product from these same developers:

If your network protocol is only exchanging input, then the bandwidth demands are tiny. At some point they realized that they could just double up packets: repeating the last inputs in the next packet. If a packet got dropped, the copy would be already transmitted before any sort of ack timeout or sequence jump would even detect the loss.