What is Connection less Service?

To send the data from one device to another device there should be a connection. The connection can be established to transfer data between the devices can be done in two ways and they are as follows −

  • Connection-Oriented Service

  • Connectionless Services

Now let us discuss the Connection less services.

Connection less Services

In connectionless the data is transferred in one direction from source to destination without checking that destination is still there or not or if it is prepared to accept the message. Authentication is not needed in this. Example of Connectionless service is UDP (User Datagram Protocol) protocol.

Connectionless service is a service that allows the transfer of information among subscribers without the need for end-to-end connection establishment procedures.

Connection-less service is sometimes known as “unreliable” network service. Connectionless protocols are usually described as stateless because the endpoints have no protocol-defined way of remembering where they are in a “conversation” of message exchange.

It is a data transmission service provided by the network and transport layer protocols.

Connectionless service is based on the postal service. Example − postal service, where the letter has source and destination address and each one of the letter routed through different paths to reach the destination.

In connectionless service, each packet of the same message may follow a different route to get delivered to the destination. In connectionless service, packets are routed based on the destination address on the packet.

For example − The Internet Protocol (IP) and User Datagram Protocol (UDP) are connectionless protocols, whereas TCP/IP is connection-oriented.


There are two types of Connectionless Service primitives, which are as follows −

  • UNIDATA − This primitive sends a packet of data

  • FACILITY, REPORT − Primitive for enquiring about the performance of the network, like delivery statistics.


The major differences between Connection oriented service and Connectionless service are as follows −

  • In connection oriented service authentication is needed and for connectionless service, an authentication is not required.

  • Connection oriented protocol creates a connection and checks whether a message is received or not and sends again if an error occurs connectionless service protocol does not guarantee a delivery.

  • Connection oriented service is more reliable when compared to connectionless service.

  • Connection oriented service interface is stream based whereas connectionless is message based.

Updated on: 17-Mar-2022


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