a Network Protocol used to provide non-guaranteed, connectionless data transport for communicating devices

Anything that relies on lowest possible latency despite loss relies on UDP.

Exists in Transport Layer

It has a Checksum. Besides that, no guarantees, unlike TCP

Datagram

Creates a “datagram” is the PDU created by UDP, and includes a UDP Header

UDP Header

a 4-field, 8-byte header containing connection and payload delivery details for a datagram. A UDP header is used to provide best-effort payload delivery.