UDP

Shouting Across a Room

TCP is like registered mail -- careful, tracked, guaranteed. But sometimes you just want to shout across the room. It's fast, but the other person might not hear you, and you won't know unless they shout back.

UDP (User Datagram Protocol) is fire-and-forget:

• Fast -- no handshake, no tracking, no waiting for ACKs
• Unreliable -- packets might be lost, duplicated, or arrive out of order
• Connectionless -- just throw the data and hope it arrives

When to Use UDP vs TCP

	TCP	UDP
Like	Registered mail	Shouting
Reliable?	Yes	No
Fast?	Slower (overhead)	Very fast
Use for	Web pages, files, email	Video calls, games, DNS

Video calls use UDP because a dropped frame is better than a delayed one. Web pages use TCP because you need every byte of the HTML.

UDP in PyNet

from pynet.udp import create_datagram

dg = create_datagram("Hello!", dest_port=9000, source_port=5000)
print(dg.data)  # "Hello!"

What We Test

• Messages can be sent and received.
• No connection setup is needed.
• Messages include the sender's address.

Next Up

HTTP opens and closes a connection for each request. What if you want to keep talking? Head to WebSocket.