| Layer Number | Layer Name | PDU Name | Description of Data Encapsulation |
|---|
| 7 | Application | Data | User data generated by applications (e.g., HTTP message) |
| 6 | Presentation | Data | Data formatted, encrypted, or compressed for transmission |
| 5 | Session | Data | Data with session management information |
| 4 | Transport | Segment (TCP) or Datagram (UDP) | Data divided into segments/datagrams with port info for reliable delivery |
| 3 | Network | Packet or Datagram | Segments encapsulated with logical addressing (IP addresses) for routing |
| 2 | Data Link | Frame | Packets framed with physical addressing (MAC addresses) and error checking |
| 1 | Physical | Bits or Symbols | Frames converted to electrical, optical, or radio signals for transmission |