OSI Model vs TCP/IP Model — What’s the Difference? If you're learning Networking, CCNA, Cybersecurity, or IT Fundamentals, you must understand these two models — they are the foundation of how data travels across networks. 💡 OSI Model (7 Layers) 1️⃣ Physical 2️⃣ Data Link 3️⃣ Network 4️⃣ Transport 5️⃣ Session 6️⃣ Presentation 7️⃣ Application ✔ Detailed, theoretical model used for learning & troubleshooting 💡 TCP/IP Model (4 Layers) 1️⃣ Network Access 2️⃣ Internet 3️⃣ Transport 4️⃣ Application