Overview of UDP protocol.
UDP (User Datagram Protocol) is a simple extension of the Internet Protocol services. It basically provides simple packet transport service without any quality of service functions.
Unlike TCP, UDP is connection-less and packet-based. Application PDUs (application packets) sent over a UDP socket are delivered to the receiving host application as is without fragmentation.
UDP is mostly used by applications with simple request-response communication patterns like DNS, DHCP, RADIUS, RIP or RPC.
Since UDP does provide any error recovery such as retransmission of lost packets, the application protocols have to take care of these situations.