I am trying to understand how Data (video, image, ...) is sent over the network, and what are the protocols and different processes involved. We know that OSPF (L3 protocol) does not use TCP or UDP, also, the FTP (File transfer Protocol - Application layer) uses the TCP to guarantee the efficiency of the transmission (resend the lost packets).
Now, I get confused, my question:
"After building the routing tables (using OSPF protocol for example), is TCP/UDP used for sending a file (like image, audio, video) from a server to a user ?"
I need clarifications.