Thank you for your explanation. That is the point that I need to know. I understand that UDP is unreliable but in which circumstance that people is going to use that protocol? Your video answer to this question. Really appreciate your effort to made this video.
Its a common missconception that UDP is an older less useful protocol, however TCP was created in 1974, UDP was created in 1980. In some cases retransmission of packets is not desireable, E.G. VOIP.