Connection-oriented services( CONS) and connectionless services( CLNS) are located on the network layer. Connection-oriented services are protocols that support connection-oriented services up to the higher layers, such as the TCP protocol.
Connectionless services are protocols that do not require a connection to be established for transmission. Connectionless Network Protocol( CLNP) is a corresponding OSI protocol, the equivalent of the IP protocol.
The classic services of the application layer include the provision of application-oriented basic services such as electronic mail, file transfer, instant messaging and many more. Print services, directory services and authentication services are used in local networks, and domain services such as the Domain NameSystem( DNS), the World Wide Web(WWW), online services, video services such as video on demand or streaming media, and Internet telephony are used on the Internet.