UDP

networking

Stands for: User Datagram Protocol

The minimal transport that wraps a packet with just ports and a checksum and sends it with no handshake, no ordering, and no retransmission: fire and forget.

Jon Postel defined UDP in RFC 768 on August 28, 1980 as the thinnest possible layer over IP, an eight-byte header carrying source and destination ports, a length, and an optional checksum. It guarantees nothing about delivery or duplicates, which is exactly why latency-sensitive and query-response traffic prefers it: its first users were the internet name service and trivial file transfer, and its descendants carry DNS, DHCP, VoIP, gaming, and the QUIC transport under modern HTTP. Where TCP is a phone call, UDP is a postcard.

Also known as: User Datagram Protocol

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