OSI & TCP/IP Models

Summary

Conceptual layered models describing how network communication works, from physical cables up through applications — the shared vocabulary ('Layer 3', 'Layer 7') used constantly in networking and infrastructure discussions.

• 1Memorize the 7 OSI layers well enough to name them in order.
• 2Learn which layer common tools/concepts (routers, firewalls, load balancers) primarily operate at.
• 3Understand the simpler, more practical TCP/IP model as the one actually used in most real systems.