The hierarchical network design model splits the network into several modular layers
There modular layer in the design model has its own area to implement their own specific functions
The hierarchical network design model provides an easy to way to scale the network and keeps a consistent deployment method.
Having several modular layers keeps the LAN design from needing a flat and fully measured network where all nodes are interconnected.
The hierarchical network design model has three modular blocks known as layers, from the top layer to bottom layer: the core layer, the distribution layer, and the access layer.
The core layer provides connections between distribution layers in larger environments. The distribution layer provides an aggregation point for the access layer and acts a a boundary between the access and core layers. Finally the access layer provides direct access to the network for the users.
A small business or enterprise may only require access and distribution layers. Whilst a larger business may need all three layers.