Application (Layer 7)
Interacts with the OS or application to provide network services needed to perform the network function that the software needs to do.
- Ex. transferring files, email,
- web browsing
Presentation (Layer 6)
Converts the data from the application layer into a format that other layers can understand.
Handles formatting, compression, and encryption.
Session (Layer 5)
Manages communication between source and destination applications. Establishes, maintains, and terminates logical connections between client and server applications.
Transport (Layer 4)
Provides end-to-end reliability between end devices.
(Achieved by segmentation, synchronization, and flow control mechanisms)
Network (Layer 3)
- Performs routing.
- Determines the path the information will take to get from the source to the destination device.
Data Link (Layer 2)
- Performs framing of the information from all layers above in the proper format for the physical network.
- Performs error detection of corrupt or missing bits in the frame.
Physical (Layer 1)
Defines the physical characteristics of the network such as connectors, cabling, voltage levels, and timing.