Which statement about the three-layer model's structure is true?

• A. It comprises Core, Distribution, and Edge layers
• B. It comprises Access, Distribution, and Core layers
• C. It includes five distinct layers
• D. It is not a layered design

Answer: (B)

The main idea here is that a three-layer network design divides responsibilities into distinct tiers: Access, Distribution, and Core. The Access layer is where end-user devices and wireless APs connect to the network. The Distribution layer aggregates traffic from multiple access devices, applies policies, performs inter-VLAN routing, and enforces security and quality of service. The Core layer serves as the fast, high-capacity backbone that interconnects distribution blocks with minimal processing delay.

This structure is what makes the model scalable and easier to manage, because changes or growth at the edge don’t have to ripple through the entire network, and policies can be centralized at the distribution layer while the core provides rapid, reliable transport.

So, the statement that it comprises Access, Distribution, and Core layers is the accurate description. The term Edge isn’t the standard label for the bottom layer in this model, five layers would exceed the conventional three-layer design, and saying it isn’t layered contradicts the fundamental architecture.