UDP, or User Datagram Protocol, is a connectionless protocol that provides fast and simple data transmission. Unlike TCP, UDP does not establish or maintain a connection between the sender and the receiver, nor does it guarantee reliable or ordered delivery of data. It simply sends packets of data without any acknowledgment, retransmission, or flow control mechanisms.

This makes UDP ideal for applications that require low latency and high efficiency, such as video streaming, online gaming, voice over IP, and real-time communication.

However, UDP also has some disadvantages. It is less reliable and secure than TCP as it does not ensure that the data is delivered correctly or at all.