UDP is a communications protocol (transport layer 4) that offers a limited amount of service when messages are exchanged between computers in a network that uses the Internet Protocol. UDP uses the Internet Protocol to actually get a data unit from one computer to another. However, UDP does not provide the service of dividing a message into packets and reassembling it at the other end. Data is transported connectionless. It does not guarantee an end-to-end control. UDP is defined in RFC 768.