UDP

UDP (User Datagram Protocol) is a connectionless, unreliable, unordered transport-layer protocol with low overhead and minimal delay, suited to real-time and broadcast traffic.

Purpose

It offers lightweight transport with no connection setup or acknowledgment, fitting real-time audio/video and DNS queries.

Mechanism

Connectionless: datagrams are sent directly with no handshake, no ACKs, and no flow control. The header is 8 bytes (source port, destination port, length, checksum). Reliability is the application's job (QUIC, for example, adds its own). Broadcast and multicast are supported.

Use cases

DNS queries (port 53)
Real-time audio/video (WebRTC)
DHCP discovery
Low-latency game traffic

Examples

Input

8-byte header + payload

Output

Sent directly, no acknowledgment

Low overhead

Common errors

UDP's unreliability loses data: Add application-layer retransmission or use QUIC

Related terms

TCP (Transmission Control Protocol) is a connection-oriented, reliable, ordered transport-layer protocol, establishing connections with a three-way handshake and providing sliding-window flow control and ACK-based acknowledgment.

A socket is a network communication endpoint identified by (protocol, local IP, local port, remote IP, remote port), serving as the interface between the application and transport layers.

A port is a transport-layer 16-bit address (0-65535) that distinguishes multiple network applications on one host; combined with the IP address it forms a socket.

Related tools

Udp Header Parser

Udp Header Parser — pure client-side tool. Privacy-first, no server round-trip.

References