I have a long question about networking that I don't know how to summarize to fit in a title. Can you read the details please?
I know the basics of networking, simple stuff. Like how data is split into packets, a group of packets is sent and won't continue sending until i formed that the previous packets have been recieved successfully, but lets just suppose a single packet is sent one at a time for the sake of simplicity.
Anyway, when you listen to FM radio, u may hear static due to interruptions of the signal. It could be interference with another signal.
My question is, let suppose ur downloading a file from a server via DSL, and while the packet is half way through, another signal has interrupted the packet and corrupted it. It is no longer the original data of the packet, it is a completely different signal that would corrupt the file. How does the computer know it is an interrupted packet? "Oh, it is worthless. I must request a resend". How does it know that? How can it be sure the signal recieved is not the original packet? What if the computer took the corrupted packet as the original signal and corrupted the whole download? how is it able to distinguish?