Engineering Tutorials

• The Physical Layer transforms data into bits that are sent across the physical media.

• The Data Link layer determines access to the network media in terms of frames. Its Media Access Control (MAC) sub layer is responsible for physical addressing.

• The Network Layer routes data through a large network.

• The Transport Layer provides end-to-end, reliable connections, often in terms of segments [Book02].

• The Session Layer allows users to establish connections using intelligently chosen names in packets.

• The Presentation Layer negotiates data exchange formats, also in terms of packets.

• Finally, the Application Layer provides the interface between the user's application and the network through messages.