Network Models and Differences

TCP/IP and OSI Model

Open System Interconnect model is a standard of the International Organization for Standardization (ISO). It is a general-purpose paradigm for discussing or describing how computers communicate with one another over a network. Its seven-layered approach to data transmission divides the many operations up into specific related groups of actions at each layer.

Transmission Control Protocol/Internet Protocol is Internet protocol suit created by US Defense Advance Research Project Agency to ensure that communication could survive in any condition and data integrity would not be compromised under malicious attacks.

The Transmission Control Protocol provides a communication service at an intermediate level between an application program and the Internet Protocol. It provides host-to-host connectivity at the Transport Layer of the Internet model. An application does not need to know the particular mechanisms for sending data via a link to another host, such as the required packet fragmentation on the transmission medium. At the transport layer, the protocol handles all handshaking and transmission details and presents an abstraction of the network connection to the application.

TCP/IP also is a layered protocol but does not use all of the OSI layers, though the layers are equivalent in operation and function. The network access layer is equivalent to OSI layers 1 and 2. The Internet Protocol layer is comparable to layer 3 in the OSI model. The host-to-host layer is equivalent to OSI layer 4. These are the TCP and UDP (user datagram protocol) functions. Finally, the application layer is similar to OSI layers 5, 6, and 7 combined.

Differences in OSI and TCP/IP   

                                               

TCP/IP is the older of the two approaches to data communications and is well established throughout the world. The OSI model, however, is a proven concept that is used in all other data communications protocols. It will continue to be used as a guideline for all other communications applications.