INTRODUCTION TO TCP/IP

TCP/IP is made up of two acronyms, TCP, for Transmission Control Protocol, and IP, for Internet Protocol. TCP handles packet flow between systems and IP handles the routing of packets. However, that is a simplistic answer that we will expound on further. All modern networks are now designed using a layered approach. Each layer presents a predefined interface to the layer above it. By doing so, a modular design can be developed so as to minimize problems in the development of new applications or in adding new interfaces. The ISO/OSI protocol with seven layers is the usual reference model. SInce TCP/IP was designed before the ISO model was developed it has four layers; however the differences between the two are mostly minor. Below, is a comparison of the TCP/IP and OSI protocol stacks: OSI Protocol Stack 7. Application -- End user services such as email. 6. Presentation -- Data problems and data compression 5. Session -- Authenication and authorization 4. Transport -- Gaurentee end-to-end delivery of packets 3. Network -- Packet routing 2. Data Link -- Transmit and receive packets 1. Physical -- The cable or physical connection itself. TCP/IP Protocol Stack. 5. Application -- Authenication, compression, and end user services. 4. Transport -- Handles the flow of data between systems and provides access to the network for applications via the (BSD socket library) 3. Network -- Packet routing 2. Link -- Kernel OS/device driver interface to the network interface on the computer. Below are the major difference between the OSI and TCP/IP: The application layer in TCP/IP handles the responsibilities of layers 5,6, and 7 in the OSI model. The transport layer in TCP/IP does not always gaurentee reliable delivery of packets as the transport layer in the OSI model does. TCP/IP offers an option called UDP that does not gaurentee reliable packet delivery.