It contains three layers: core, distribution, and access. In a three-layer hierarchical model for Cisco routers, The first layer is the local area network (LAN) that uses I EEE 802. 3 Ethernet technology to connect devices on the same physical segment (or subnet). This low level of networking provides easy sharing of media and files between individual. Cisco suggests a Three−Tier (Three Layer) hierarchical network model, that consists of three layers: the Core layer, the Distribution layer, and the Access layer. The. A core switch is the backbone of a large-scale network, designed to handle massive volumes of traffic with ultra-low latency and maximum reliability. Each of layers has its own features and functionality, which reduces network complexity.