In the Cisco hierarchical model, which layer is typically responsible for policy enforcement and inter-VLAN routing?

In the Cisco hierarchical model, which layer is typically responsible for policy enforcement and inter-VLAN routing?

• A. Core
• B. Access
• C. Enterprise
• D. Distribution

Answer: (D)

Policy enforcement and inter-VLAN routing happen at the distribution layer. This layer sits between the access switches (where end devices plug in) and the core, acting as the gateway between VLANs and a place to apply network-wide policies. It aggregates traffic from multiple access switches and provides L3 routing between VLANs, typically using SVIs or routed interfaces, while also enforcing ACLs, QoS, and security boundaries. The core is focused on fast, reliable transport of traffic between distribution switches and does not handle policy enforcement or inter-VLAN routing. The access layer is mainly about connecting end devices and forwarding frames upward, not performing inter-VLAN routing. In many designs, the Enterprise term refers to the broader network rather than a dedicated layer with these functions.

Policy enforcement and inter-VLAN routing happen at the distribution layer. This layer sits between the access switches (where end devices plug in) and the core, acting as the gateway between VLANs and a place to apply network-wide policies. It aggregates traffic from multiple access switches and provides L3 routing between VLANs, typically using SVIs or routed interfaces, while also enforcing ACLs, QoS, and security boundaries. The core is focused on fast, reliable transport of traffic between distribution switches and does not handle policy enforcement or inter-VLAN routing. The access layer is mainly about connecting end devices and forwarding frames upward, not performing inter-VLAN routing. In many designs, the Enterprise term refers to the broader network rather than a dedicated layer with these functions.