What Is Datagram? - ITU Online

What Is Datagram?

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In the world of digital communication, a datagram plays a crucial role. It’s a unit of data that’s transmitted across a network without prior arrangement or setup between the sending and receiving parties. This method of data transfer is fundamental to the design of the Internet, particularly within the User Datagram Protocol (UDP), which is one of the core members of the Internet protocol suite.

Understanding Datagram

A datagram is designed to be a self-contained packet of information. It includes everything necessary to deliver it to its destination, such as the source and destination addresses. Unlike in a connection-oriented communication, datagrams are sent to the recipient without establishing a dedicated path beforehand. This approach, known as connectionless communication, allows for data to be sent quickly but without guarantees for delivery, order, or data integrity.

Benefits and Uses

The primary advantage of using datagrams in networking is the speed and efficiency of data transmission. Since there’s no need to establish a connection before sending data, datagrams can be dispatched immediately, making them ideal for time-sensitive applications like live video streaming, online gaming, and voice-over-IP (VoIP) services. However, the trade-off for this efficiency is the potential for data loss, duplication, or receiving datagrams out of order.


  1. Connectionless Nature: Datagrams are sent without establishing a prior connection, leading to faster data transfer.
  2. Self-Contained Packets: Each datagram contains enough information (e.g., source and destination addresses) to be routed independently through the network.
  3. Efficiency in Transmission: Suitable for real-time applications where speed is more critical than reliability.

How Datagrams Work

When a datagram is sent, it traverses the network from the sender to the receiver, potentially passing through various routers and switches. At each point, the routing decision is made based on the destination address contained within the datagram. This process ensures that datagrams find their way through the network, leveraging the most efficient path available at the time of transmission.

Frequently Asked Questions Related to Datagram

What is the difference between a datagram and a packet?

A packet is a broad term for a piece of data sent over the network, whereas a datagram is a specific type of packet used in connectionless communications, primarily with UDP.

How do datagrams handle data integrity and order?

Datagrams do not inherently provide data integrity, order, or delivery guarantees. Applications using datagrams must implement their mechanisms for these features if needed.

Can datagrams be used for all types of online communication?

While datagrams are efficient for real-time or streaming applications, they may not be suitable for use cases requiring reliable data transmission, where TCP or similar protocols would be preferred.

What protocols use datagrams?

The most common protocol that uses datagrams is the User Datagram Protocol (UDP), though other protocols, like the Internet Group Management Protocol (IGMP), also use datagrams.

Are there any limitations to using datagrams?

The main limitations include the lack of delivery guarantees, potential for data duplication, and the need for applications to manage data ordering and integrity.

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