Hierarchical Network Model

Access layer

• Provides user access to network.

• Generally incorporates switched LAN devices that provide connectivity to workstations, IP phones, servers, and wireless access points.

• For remote users or remote sites provide an entry to the network across WAN technology.

Distribution layer

• Aggregates LAN devices.

• Segments work groups and isolate network problems.

• Aggregates WAN connections at the edge of the campus and provides policy-based connectivity.

• Implements QoS policies.

Core layer

• A high-speed backbone.

• Core is critical for connectivity, must provide a high level of availability and adapt quickly to changes.

• Should provide scalability and fast convergence.

• Should provide an integration point for data center.