Chapter 15 / 15.6 / 15.6.3

15.6.3 User Datagram Protocol (UDP)

Not every application requires guaranteed delivery. Some applications, particularly those involving real-time communication, are more concerned with minimizing delay than ensuring that every packet arrives successfully. These applications commonly use the User Datagram Protocol (UDP).

Unlike TCP, UDP does not establish a connection before transmitting data and does not attempt to recover lost packets. Each packet is transmitted independently with minimal protocol overhead.

UDP is therefore well suited to applications such as:

• VoIP;
• video conferencing;
• live media streaming;
• online gaming; and
• DNS queries.

If an occasional packet is lost, these applications generally continue operating without noticeable interruption.