The core is in charge of transporting traffic between core POPs. This traffic can come from the operator’s customers (aggregated via access and MAN networks), local or regional data centers, or other operators. This network segment provides a transport facility to service DIF across the provider’s main POPs. It deals with highly aggregated traffic carried governed by (very) different QoS promises.

This network provides a sophisticated design suitable for very large core networks, ready to scale-up if needed. In this design, we find 2 levels of backbone DIF, L1 and L2. Backbone Level 1 aggregates the traffic over several MAN core POPs into regional core POPs. These regional core POPs are all interconnected by Backbone Level 2. Backbone Level 1 is further divided into different areas, which map to the regions in the provider’s network. Its structure can be leveraged to design an effective addressing and forwarding scheme.