What Is UDP?

April 15, 2024

UDP, or User Datagram Protocol, is a fundamental piece of the internet's communication framework. It allows computers to send messages, known as datagrams, to other systems on an IP network without requiring prior communications to set up special transmission channels or data paths.

What Is UDP (User Datagram Protocol)?

UDP is one of the core protocols of the Internet Protocol Suite, which is used alongside Transmission Control Protocol (TCP). It is used across the internet for time-sensitive transmissions such as video playback or gaming. It is a simpler, connectionless protocol, where error-checking and tracking mechanisms are minimal or absent. This absence allows for faster data transfer rates, although it also increases the risk of errors and lost data.

UDP neither ensures that the target receives all data sent nor confirms the order of data packets, making it less reliable but more efficient for certain applications where speed is more critical than accuracy.

UDP Features

Here are some key features of UDP:

  • Connectionless communication. UDP does not establish a connection before sending data.
  • Speed. It offers minimal delay in data transmission.
  • Efficiency. It is suitable for applications that require quick transmission of small amounts of data.
  • No error correction. It does not recover lost packets or handle packet order, relying on the application to manage these concerns.
  • Non-blocking. UDP allows applications to continue running even if some datagrams are lost.

How Does UDP Work?

UDP (User Datagram Protocol) works in a straightforward and efficient manner, emphasizing speed over reliability in data transmission. Here’s a breakdown of how UDP operates:

  1. Packet creation. The process begins with an application that wants to send data. This data is divided into smaller blocks, known as datagrams. Each UDP datagram contains both the data payload and a header with necessary addressing information, including the source and destination port numbers, the datagram's length, and a checksum to verify data integrity.
  2. No connection establishment. Unlike TCP, UDP does not establish a connection before sending data. There is no handshake between the sending and receiving parties, which eliminates the delay caused by setup procedures.
  3. Data transmission. Once the datagram is ready, it is handed over to the IP network layer, which encapsulates the UDP datagram within an IP packet and sends it off to the destination. UDP itself does not track the datagram after sending—it simply sends the data.
  4. Minimal error checking. At the receiving end, the UDP protocol layer processes the received datagrams. This involves checking the checksum to ensure the data is not corrupted. However, if a checksum fails, the packet is silently dropped. UDP does not attempt to resend data.
  5. No order assurance or reliability. UDP does not ensure that datagrams arrive in the order they were sent or even guarantee that they arrive at all. It is the responsibility of the application using UDP to handle these issues if necessary.
  6. Handling incoming data. Applications that use UDP are typically designed to handle losses or reordering of datagrams. For instance, a video streaming application may simply skip a missing packet, while a more interactive application might implement its own methods for requesting retransmission.

UDP Use Cases

Because of its simplicity and lack of connection management, UDP is significantly faster and more efficient for applications that can tolerate some loss of data, such as video streaming, online gaming, and voice over IP (VoIP). This efficiency makes it a crucial protocol in real-time communications where latency is a key concern. UDP is particularly useful in these use cases:

  • Streaming video and audio. It's used where missing packets are preferable to delays (e.g., live broadcasts).
  • Gaming. Delivers fast and efficient real-time communication necessary for online multiplayer games.
  • DNS lookups. Transmits small query and response packets quickly.
  • IoT devices. Sends small data packets from thousands of devices with lower processing power and less bandwidth.
  • VoIP. Enables fast and efficient transmission of voice data, tolerating minor packet losses that are less noticeable in voice communication but significantly reduce latency and improve call quality.


Comparing UDP and TCP helps highlight their appropriate uses.

  • Top of Form
 TCP (Transmission Control Protocol)UDP (User Datagram Protocol)
ReliabilityEnsures packet delivery and order.Does not guarantee packet delivery or order.
Connection setupRequires a handshake to establish a connection, which can introduce delays.Sends data without the need for establishing a connection, therefore no delays.
Use caseBetter suited for applications where data integrity and order are crucial (e.g., file transfers).Preferred for real-time applications where speed is critical (e.g., live streaming, online gaming).
OverheadHas more overhead due to its mechanisms for ensuring data reliability and order.Has less overhead, reducing the amount of data sent over the network.

Nikola is a seasoned writer with a passion for all things high-tech. After earning a degree in journalism and political science, he worked in the telecommunication and online banking industries. Currently writing for phoenixNAP, he specializes in breaking down complex issues about the digital economy, E-commerce, and information technology.