The aggregation or distribution switches are the intermediary layer between the core and access layers. The lowest tier is the access layer, which is used to connect all of the various end devices, such as PCs, printers, and other network components such as routers or. The three layers of a traditional three-layer network design are the core layer, aggregation layer, and access layer. Together, these layers can offer consumers a network that is safe, reliable, and affordable. Why would a large enterprise need an. Learn about aggregated Ethernet interfaces, LACP, and LAG.