• Physical Layer - The actual hardware.

• Data Link Layer - Data transfer method. Places data in frames and make sure error free transmission. Also manages the timing of the network transmission. Adds frame type, address, and error control information.

• Network Layer - IP network protocol. Routes messages using the best path available.

• Transport Layer - TCP, UDP. Make sure correctly sequenced and error free transmission.

• Session Layer - The user's boundary to the network. Find out when the session is start or opened, how long it is used, and when it is closed. Controls the diffusion of data during the session. chains security and name search for enabling computers to place each other.

• Presentation Layer - ASCII or EBCDEC data syntax.

• Application Layer - offers services software applications require. Provides the capacity for user applications to interact with the network.