Das OSI-Modell
| Data Unit | Layer Name | Layer Number | Services | Netzwerkgeräte |
| Raw Data | Appplication | Layer 7 | HTTP, FTP, DNS | |
| Raw Data | Presentation | Layer 6 | ||
| Raw Data | Session | Layer 5 | TLS | |
| Segments | Transport | Layer 4 | TCP, UDP | |
| Packets / Datagrams | Network | Layer 3 | IP, ARP, ICMP | Router |
| Frames | Data Link | Layer 2 | MAC | Switch, Access Point |
| Bits | Physical | Layer 1 | Ethernet | Hub |