The OSI model defines seven layers, from top to bottom:
- Application
- Presentation
- Session
- Transport
- Network
- Data Link
- Physical
In contrast, the TCP/IP model simplifies this to four layers, from top to bottom:
- Application
- Internet
- Transport
- Network Access
Specifically, the top three layers of the OSI model are consolidated into the Application Layer in TCP/IP, while the Transport layer remains the same. The Network layer is renamed to the Internet layer, and the last two layers of the OSI model are combined into the Network Access layer in TCP/IP.
| OSI MODEL | TCP/IP MODEL |
|---|---|
| Application | Application |
| Presentation | |
| Session | |
| Transport | Transport |
| Network | Internet |
| Data Link | Network Access |
| Physical |