Free Subnet Calculator — IP Subnetting Tool Online
Free online subnet calculator — enter any IP address and CIDR prefix to instantly get subnet mask, network…
OSI Model Quiz — 20 Questions
Test your understanding of the OSI (Open Systems Interconnection) model with this free 20-question quiz. Perfect for CCNA, CompTIA Network+, and networking interview preparation.
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OSI Model Quiz
20 questions • ~5 minutes • Instant results
OSI Model Quick Reference
| Layer | Name | PDU | Protocols/Devices | Function |
|---|---|---|---|---|
| 7 | Application | Data | HTTP, FTP, DNS, SMTP | User interface, network services |
| 6 | Presentation | Data | SSL/TLS, JPEG, MPEG | Encryption, encoding, compression |
| 5 | Session | Data | NetBIOS, RPC, SQL | Session management |
| 4 | Transport | Segments | TCP, UDP | End-to-end delivery, ports |
| 3 | Network | Packets | IP, OSPF, BGP, Routers | Logical addressing, routing |
| 2 | Data Link | Frames | Ethernet, MAC, Switches | Physical addressing, error detection |
| 1 | Physical | Bits | Cables, Hubs, NICs | Raw bit transmission |
Ready to go deeper? Read our complete guide on network devices and what OSI layer they operate on, or practice with our subnet calculator to test your Layer 3 knowledge.
