What function does the collapsed core perform in a two-tier network architecture?

In a collapsed core architecture, the core and distribution layers are combined into a single layer. This combined layer is responsible for enforcing routing policies, as it handles inter-VLAN routing and acts as the central routing point for the network. It determines the optimal paths for data traffic between different network segments. Marking interesting traffic for data policies is typically done at the access layer or by specialized devices like firewalls. Applying security policies is a function often distributed across multiple layers, including access, distribution (if separate), and dedicated security appliances. Attaching users to the edge of the network is the primary function of the access layer.