connection oriented network service (CONS)

A Connection Oriented Network Service(CONS) exists when subsystems have established a logical connection( session) and exchange information over a longer period of time via the underlying layers.

Connection Oriented Mode is based on Virtual Circuits ( VC) that are established to handle communication. This mode is usually used in wide area networks and has the advantage that all data packets arrive at the receiver in the correct order, no data packets are lost and the network is not burdened with undeliverable data packets. TCP/ IP is an example of a connection-oriented transport protocol.

As an alternative to the connection-oriented services, there are the connectionless services, the Connectionless Network Services( CLNS), which work with datagrams and deliver the datagrams according to the principle of best- effort delivery.