UDP-User Datagram Protocol | Pros and Cons, and Need

In this blog, we will tell what UDP is and the advantages and disadvantages of this protocol. If you read it completely, you will understand easily. So let’s start reading:-

User Datagram Protocol

UDP is a protocol whose full name is User Datagram Protocol. This protocol was designed by David P Reed in 1980. It is defined in RFC 768.

It is the transport layer communication protocol of the OSI model. It is a connection-less protocol, meaning when data transfer takes place between two computers, this protocol does not establish a connection between the sender and the receiver.

In UDP, the receiver does not generate any acknowledgment for receiving the data and the sender does not generate any acknowledgment for sending the data. It transfers data directly.

The use of communication mechanisms in this protocol is very less. User Datagram Protocol is also called unreliable protocol but it uses IP protocol service which provides the best delivery mechanism.

In the user datagram protocol, the data packet is called a datagram. This protocol does not give any guarantee that your data will reach its destination or not. This data can also reach in small quantities (because some data packets may also get destroyed in the middle of data transmission).

It is also not necessary in this protocol that the data sent by you will reach the receiver in the same sequence in which we have sent the data. It does not send back the data segment (ie it does not retransmit the lost data packets).

Why is User Datagram Protocol Needed?

  • User datagram protocol is used to transfer such data where we need speed more than accuracy and reliability as it gives fast service as compared to tcp.
  • If the data flow is in only one direction then this protocol can be used.
  • User datagrams are used for streaming applications.
  • User datagram is a connection-less protocol.

Advantages of User Datagram Protocol

Its benefits are as follows:-

  • Using this protocol, we can do broadcast and multicast transmission.
  • It uses small size data packet with a small header (8 bytes). Due to which it takes less time to process the data packet and the memory usage is less.
  • In this protocol, there is no need to establish and maintain the connection.
  • There is no acknowledgment in this, because of this its speed also increases.
  • Whenever a data packet has to be transmitted in a single direction, UDP is used.

Disadvantages of User Datagram Protocol

Let us now know some of its disadvantages:-

  • This is an unreliable transport protocol.
  • There is no such function in this protocol to know that the data has been received.
  • This protocol is not able to control the congestion
  • Using routers with user datagram also has the disadvantage that once there is congestion, the routers cannot transmit the datagram again.

User Datagram Protocol Header

The user datagram header is very simple. Its size is 64 bit. (64 bit means 8 bytes)


It consists of four parameters:-

  • Source port
  • Destination port
  • Length
  • Checksum
Source port–

The size of this source port is 16 bit. Which is used to identify the source port of the data.

Destination port-

Its size is 16 bit. Which is used to identify the destination port of the data.


It defines the length of the datagram (Data). It stores the length of the data and the header.


It works to store the checksum value which is generated by the sender before sending it.


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