Quiz Entry - updated: 2026.07.14
What are the seven layers of the OSI model and their functions?
7 Application, 6 Presentation, 5 Session, 4 Transport, 3 Network, 2 Data Link, 1 Physical — top handles app data, bottom handles physical transmission.
* The seven OSI layers, top to bottom, with each layer's job. *
| Layer | Name | Function |
|---|---|---|
| 7 | Application | Protocols used for process-to-process communications |
| 6 | Presentation | Common representation of data transferred between application layer services |
| 5 | Session | Provides services to the presentation layer and manages data exchange |
| 4 | Transport | Defines services to segment, transfer, and reassemble data for individual communications |
| 3 | Network | Provides services to exchange individual pieces of data over the network |
| 2 | Data Link | Describes methods for exchanging data frames over a common media |
| 1 | Physical | Describes the means to activate, maintain, and de-activate physical connections |
Go deeper:
OSI Model Explained — real-world example — walks each of the seven layers with a concrete example.
OSI model — authoritative description of all seven layers and their functions.