What Is UDP?

Date First Published: 22nd February 2022

Topic: Computer Networking

Subtopic: Internet Protocols

Article Type: Computer Terms & Definitions

Difficulty Level: 8/10

Learn more about what UDP is in this article.

Short for User Datagram Protocol, UDP is a communication protocol and a core part of the TCP/IP protocol. It is used for time-sensitive transmissions, such as video playing, media streaming, gaming, live broadcasts, and DNS lookups. These communications are time-sensitive, since if there was a lot of latency in a video call, frequent pauses would occur, disrupting the normal flow of the video call. UDP has been around since 1980. It was introduced by David Reed and defined in RFC 768.

How Does UDP Work?

UDP works by establishing a low-latency connection between applications on the internet and saves time by allowing data to be transmitted before an agreement is provided by the receiving party. This allows data to be transmitted more quickly, but it also increases the risk of packets being lost whilst they are travelling, which can be exploited through DDoS attacks.

What Is The Difference Between UDP and TCP?

UDP is used as an alternative to TCP. It can also come before IP and is sometimes referred to as UDP/IP. The main difference is that UDP enables process-to-process communication and TCP supports host-to-host communication. UDP is known to be less reliable than TCP because TCP communication works by two computers beginning to connect by an automatic process, called a handshake and the data packets will only be transferred once the handshake is finished. In UDP communications, one computer can just begin transferring data to the other computer and it does not go through this process. It is known as a 'stateless' protocol, since it doesn't acknowledge that the packets being sent have been received.

Another difference between UDP and TCP is that the order that data packets should be received is indicated by TCP communications and it confirms that data packets arrive as intended. In addition, TCP requires data packets to be resent if a packet fails to arrive. None of this functionality is included in UDP communications.