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| 2.1 |  | Using a Layered Architectural Model to Describe Data Flow |
| 2.1.5 |  | OSI model versus TCP/IP model |

Similar to the OSI networking model, the TCP/IP networking model divides networking architecture into modular layers. Figure shows how the TCP/IP networking model maps to the layers of the OSI networking model. It is this close mapping that allows the TCP/IP suite of protocols to successfully communicate with so many networking technologies.

The TCP/IP network access layer corresponds to the OSI physical and data-link layers. The network access layer communicates directly with the network media and provides an interface between the architecture of the network and the Internet layer.

TCP/IP Internet layer relates to the OSI Network layer. The Internet layer of the TCP/IP protocol model is responsible for placing messages in a fixed format that allows devices to handle them.

The transport layers of TCP/IP and OSI directly correspond in function. The transport layer is responsible for exchanging packets between devices on a TCP/IP network.

The application layer in the TCP/IP suite actually combines the functions of the three OSI model layers which are session, presentation, and application. The application layer provides communication between applications such as FTP, HTTP, and SMTP on separate hosts.