CCNP Data Center Question of the Week: Aggregation Layer

Answer: B, E and G.

Cisco recommends a three layered model for the data Center, for scalability and reliability. The three layers are Access, Aggregation and Core. The aggregation layer is the L3 and L2 boundary for the data center infrastructure. In common designs, the aggregation layer is also the connection point for data center firewalls and other services. Thus, it consolidates L2 traffic in a high-speed packet switching fabric and provides a platform for network- based services at the interface between L2 and L3 in the data center. Typically, the aggregation layer is made up of two or more switches and is the demarcation point for the VLANs facing into the access layer and the path into the core. This is where we would run our FHRP (like HSRP or VRRP); routing and layer 3 filtering would be applied; and where QoS policy would be applied.