Tcp and udp are to sum it up, internet messaging protocols. UDP specifically is when you send a message over without guaranteeing your message was received. TCP on the otherhand is more like a handshake where you send a message and expect a response back.

The joke is basically UDP=I dont know if you would get it

Yeah I believe i remember roughly the explanation I gave to the interviewer.

TCP basically takes the time to confirm every detail actually was recieved, used in almost all situations in networking where accuracy is critical.

UDP is basically when speed is the more important than everything being perfect, (we were on a zoom call), Like say this video call, if the background gets blurry or a few frames drop or even my face distorts for a few seconds, that would be less of an inconvenience to us than if the network took the time and made sure to transmit every frame exactly as the camera picks it up, at the cost of an extra 10 seconds of lag in the call.

There's pretty basic UDP, that sends without confirming receiving. And instead of fixing it, they just slapped another protocol, TCP, on top of it.

With only UDP, you don't know, if you get it.