The UDP is process to process protocol that adds only port address, check-sum error control and length information to the data from the upper layer.

The TCP provides full transport layer services to application. TCP is a reliable stream transport protocol. The term stream in this context means connection-oriented: a connection must be established between both ends of a transmission before either can transmit data.

The application layer in TCP/IP is equivalent to the combined session, presentation and application layer in the OSI model. Many protocols are defined at this layer.