When postal mail is not registered, there is a small chance that the letter we send might never be seen again. The letter is addressed and sent and no more effort is spent on it. It is a matter of the mail carrier doing its job correctly. It is the same case with UDP.

A UDP header containing an IP address and a port number is wrapped around whatever data needs to be sent, and the packet is handed over to the IP layer. As long as the lower layers do their jobs correctly, the remote end should receive the datagram as expected. There are no acknowledgement counters and no connection states.