Two Models, One Reality

You’ll hear references to both the OSI Model (7 layers) and the TCP/IP Model (4 layers). Understanding how they relate prevents confusion.

The difference:

• OSI Model — theoretical reference, great for teaching and troubleshooting
• TCP/IP Model — what actually runs on networks

In Practice

People use OSI layer numbers even when discussing TCP/IP protocols. “Layer 2 switch” and “Layer 3 routing” are OSI terminology applied to real-world networking.