The UDP protocol is a lightweight, connectionless transport layer protocol in computer networking. It provides best-effort, low-overhead data transmission without TCP's reliability and sequencing features.
UDP is faster but less reliable than TCP, making it suitable for real-time applications like video streaming and VoIP, where minor data loss is acceptable. Unlike TCP, UDP does not establish a connection or ensure data delivery, making it more efficient for broadcasting and multicasting.
Its simplicity, low latency, and minimal overhead make it ideal for applications prioritizing speed over error correction and ordered data delivery.
Because of its simplicity, the UDP header is an 8-byte segment at the beginning of a UDP packet and contains source and destination ports, length, and checksum. As you can see in the image above, the UDP header is much simpler than the TCP header because it lacks complex control fields for sequencing, acknowledgments, and flow control, making UDP more lightweight and efficient for applications prioritizing speed over reliability.
Because some applications prioritize speed and responsiveness over perfect data delivery, UDP is a suitable choice despite its lack of reliability compared to TCP. Such applications are:
- Voice and video calls
- Streaming services
- DNS
- Online gaming