UDP

Problem

Sometimes an application just wants to send a small message: Here are some bytes for application X on that machine. It doesn't necessarily want connection setup, retransmission, ordering or reliability.

Solution — UDP

UDP stands for User Datagram Protocol.

UDP adds ports to IP and sends independent datagrams:
10.0.0.1:53000
      ↓
10.0.0.2:53

If one disappears, UDP itself does nothing about it.

Core idea: UDP provides minimal process-to-process delivery on top of IP.