TCP/IP

Transmission Control Protocol (TCP) was developed before the OSI Model.TCP/IP protocol is made of five layers: Physical Layer. Data link Layer, Network, Transport and Application. The application layer in TCP/IP can be equated with the combination of session, presentation and application layer of the OSI model. At the transport layer, TCP/IP two protocols TCP and user datagram protocol. At the network layer the main protocol defined by TCP/IP is internetworking protocol (IP), although there are some other protocols that support data movement in this layer. At this physical and data link layer TCP/IP does not defines any specific protocol. A network in a TCP/IP internetwork can be LAN, MAN, WAN.

TELNET          FTP          SMTP       DNS

TCP                                            UDP

IP

ARPANET                          SATNET LAN

TCP is a connection oriented end to end protocol. The protocol works in collaboration with IP and adds security and reliability to the features of IP.