Three-Tier

The three-tier architecture organizes a network into three distinct layers: the core, distribution, and access layers. The core layer provides high-speed backbone connectivity between distribution blocks and is optimized purely for fast packet forwarding with no policy enforcement. The distribution layer handles routing, filtering, and policy between the core and access layers, while the access layer connects end-user devices to the network. This design is the traditional standard for large enterprise campus networks where scalability, redundancy, and clear separation of functions are critical.