I don't understand this ?
The OSI model and TCP/IP model are the language that every networking professional speaks. Every Cisco command, every troubleshooting step, and every design decision references these models. When a senior engineer says "the problem is at Layer 2," everyone in the room immediately narrows the scope: it's a switching or cabling issue, not a routing or application issue. When someone says "this is a Layer 4 problem," the team knows to check port numbers and transport protocol behavior, not IP routing tables.
Answers
It's the way a router operates