In Cisco's hierarchical internetworking model, which layer serves as the communication point between the Access Layer and the Core Layer?

• A. Distribution Layer
• B. Access Layer
• C. Core Layer
• D. Aggregation Layer

Answer: (A)

The idea being tested is how Cisco's hierarchical internetworking model assigns responsibilities to each layer and which one sits between the access devices and the backbone.

The distribution layer is the communication point between the Access Layer and the Core Layer. It acts as the aggregation point for traffic from multiple access switches, and it enforces policies, performs inter-VLAN routing, and handles security, QoS, and redundancy. This layer sits at the boundary where local access traffic is prepared for rapid transport through the backbone, while keeping the Core Layer focused on fast, high-speed data transport without heavy policy processing.

The Access Layer connects end devices and passes traffic upward; it doesn’t perform inter-VLAN routing or policy enforcement for multiple VLANs. The Core Layer is the backbone optimized for speed and minimal processing, not a boundary where routing policies are applied. While the term Aggregation Layer is sometimes used, the standard Cisco model typically designates the boundary between access and core as the distribution layer.