blog posts

What Is the UDP (User Datagram Protocol) Protocol?

The Connection Of Systems In Local Home And Corporate Networks As Well As Public Networks Such As The Internet Is Done By Default Based On The Internet Protocol Family. 

The Connection Of Systems In Local Home And Corporate Networks As Well As Public Networks Such As The Internet Is Done By Default Based On The Internet Protocol Family.

The most well-known component of this protocol is the Internet Protocol  (IP), which is responsible for addressing and segmenting data packets and defines how to describe source and destination information.

However, data transmission is usually done through a  Connection  Control Protocol (TCP), which is why networks are often referred to as TCP / IP networks. Because TCP provides security and delays transmission, David Patrick Reid introduced his concept of User Datagram Protocol (UDP) in 1980 as an easier and faster option for the standard protocol.

This article will introduce you to the type of network protocol, the UDP protocol, which stands for User Datagram Protocol.

UDP is part of the Internet Protocol suite, called the UDP / IP suite.

Unlike TCP, this protocol is unreliable and offline. Therefore, there is no need to communicate before data transfer.

Although the Transfer Control Protocol (TCP) is the primary transport layer protocol used in most Internet services and provides secure delivery, reliability, and more, these services will come at additional costs and delays.

User Information Protocol (UDP) is more efficient in latency and bandwidth. UDP is used for instant services such as computer games, audio or video communication, and live conferencing. There is no error in UDP, so it also causes bandwidth.

What is the UDP protocol?

User Datagram Protocol (UDP) is a communication standard for exchanging data. UDP prioritizes speed over reliability by using an offline process to send data packets to the destination. Due to its low latency, UDP is suitable for time-sensitive applications such as video streaming, Voice over Internet Protocol (VoIP), video games, and Domain Name System (DNS) search.

When higher-level protocols require fast data transfer, they rely on UDP to package and distribute this data over the Internet Protocol (IP).

What is the UDP protocol?

Like many other network protocols, UDP  belongs to the Internet Protocols family. It is classified as an intermediary between the network and application layers at the transport level.

An application can send information quickly Using the User Datagram Protocol because you do not have to communicate with the recipient or wait for a response. However, there is no guarantee that the packages will be sent incomplete and in exact order.

In addition, the protocol does not protect against tampering or access by third parties. However, defective packets can detect with an optional usable control check  (in combination with mandatory IPv6).

UDP headers

Like UDP, TCP tags data packets with a single header. But UDP headers are much more straightforward. There are only four areas:

  1. Source port
  2. Target port
  3. UDP length
  4. checksum

The source port indicates where the transfer is taking place. The destination port shows where it is going. The UDP length specifies how many bytes the title and data representation, and the checksum is a field that can use to check for errors in the header or data stream.

TCP has several additional sections in the title that help you keep data packets safe and can be rearranged if necessary. These extras significantly increase the size of the header.

UDP features at a glance

To understand in detail how  the packet transfer works  with this protocol, let’s take a closer look at the characteristics of the Datagram user protocol:

  1. UDP is offline: The feature of data transfer via UDP is done without the existing connection between the recipient and the receiver. The relevant packets are then sent to the preferred IP address without specifying the need to respond to the computer and select the desired port.
    However, if packets are also to be returned to the recipient, the UDP header can optionally include the source port as well.
  2. UDP uses a port: Like UDP, TCP uses a port to move packets to the correct protocols or applications in the target system. Ports are defined according to a pattern proven by numbers, and numbers between 0 and 1023 are assigned to fixed services.
  3. UDP enables fast and delay-free communication: The transport protocol is suitable for fast data transfer due to the lack of connection setup. The loss of separate packages only affects the quality of transmission.
    On the other hand, missing packets are automatically retrieved with TCP connections, leaving the entire transfer process deadlocked.
  4. UDP does not guarantee data security and integrity: Lack of cross-authentication between the recipient and the receiver ensures excellent UDP transmission speed. However, the protocol can neither guarantee the completeness nor security of data packets.
    The correct sequence of submitted packages is also not guaranteed. For this reason, services that use UDP must take specific steps to modify or protect it.

How is the UDP header made?

As is usual for protocols, UDP packets consist of a header and accurate user information.
The UDP header contains all the information needed to transfer data using the transport protocol, making a UDP packet identifiable in the same way.
The data in the table is divided into  two 32-bit blocks  with four different data sections; the structure is as follows:

Bits 0 – 15 Bits 16 – 31
0 Source port Target port
32 the length checksum

✔ The first 16 bits of the header area indicate the source port through which the corresponding data packet is sent. The receiver needs this information to be able to respond to the package. It is optional because the UDP  is offline and does not exchange between the recipient and the receiver. Therefore, the value “0” is usually set here.

✔ In the next section,  the target port and, therefore, the access service is specified. Unlike the source port, this information is mandatory. Otherwise, the data cannot identify correctly.


If an application is client-side, the dedicated port number may be unstable. If the port is assigned to a server process, the port number is usually one of the “known ports” (standard ports).

Length The length field specifies the length of the datagram. It includes header length : (8 bytes) and user data size  (maximum theory: 65,535 bytes). When using IPv4, the actual limit for user data is 65507 bytes. In IPv6, packets (so-called jambograms) that are longer than the maximum are also possible. According to RFC 2675, the length field value is set to “0” in this case.

DP The UDP header terminates in the checksum, which detects errors during transmission. In this way, any manipulation of the transmitted data can be seen.

The last word

The scope of use of UDP is limited but shows the enormous value of the protocol. The Datagram user protocol has a minimalist structure and missing mechanisms to ensure a complete and successful transfer but can not be used as a global transport protocol. Instead, it is designed from the ground up for applications that do not yet require a secure transfer service.