The network core layer provides connectivity to other parts of the network, mainly to the aggregation modules. As a result, it’s tasked with forwarding packets between the different sections of the network since it provides high-speed switching services.

The aggregation or distribution layer is an access point for devices that provide services to all server farms on the network.  This layer contains protocols as well as features that support layer 3 and layer 2 connectivity. Hence, its where traffic control takes and also provides services such as load balancing and security, such as firewalling and intrusion detection to servers across the access layer devices.

The access layer is where the end-users connect to the network. It also provides layer 2 connectivity and layer 2 features on the network. The switches provide layer 2 and layer 3 with intelligent network services that enable front-end servers to provide their functions. The access layer also acts as middleware, and provide storage services.