The Byzantine Empire used a system of beacons to transmit messages across Asia Minor to Constantinople. The main line of beacons stretched over some 450 miles . A message could be transmitted the entire length of the line within an hour.
https://mapsontheweb.zoom-maps.com/post/177233097998/the-byzantine-empire-used-a-system-of-beacons-to
@onlmaps I wonder what analogues of ping, what kind of transport control protocol they used! Also, if they had checksums.