UDP Explained: The Need for Speed Over Reliability

Fire and Forget

While TCP focuses on guaranteed, perfect delivery of data, the User Datagram Protocol (UDP) takes the opposite approach. UDP is designed for pure speed and efficiency. It does not establish a connection beforehand, it does not check if packets arrived in the correct order, and it never asks for lost packets to be resent.

With UDP, the server simply fires the data packets at your IP address as fast as it can and hopes they arrive. If a packet gets lost along the way, it is gone forever.

TCP: "Here is packet 1. Did you get it? Okay, here is packet 2."
UDP: "Here is packet 1, 2, 3, 4, 5! Good luck!"

When Losing Data is Acceptable

Why would we ever want to use a protocol that loses data? The answer lies in real-time applications like live video broadcasting, Zoom calls, and fast-paced multiplayer gaming.

If you are watching a live Twitch stream and a single packet containing a fraction of a frame of video gets lost, it is better for the video player to simply skip that missing piece and keep playing. If the stream used TCP, the video would freeze entirely while it waited for the missing data to be resent, resulting in endless buffering.

Why This Affects Your Speed Test

Your speed test metrics give you a direct window into how UDP traffic will perform on your network. Since UDP does not correct errors, it is highly sensitive to Packet Loss and Jitter. If your speed test shows high jitter or any packet loss, you will experience stuttering on Zoom calls and rubber-banding in online games, because those dropped UDP packets are never recovered.