High level architecture of VCNs
VCNs are implemented by creating an overlay network over the substrate network that is hosting the physical hosts. The overlay network provides address space separation between the substrate network and the customer visible VCN and provides the ability to place and migrate networking resources independent of the underlying network topology.
With the overlay network, a network packet-encapsulation mechanism is used to hide the overlay IP addresses from the underlying substrate network. The packet encapsulation is implemented on a smart chip installed on the compute nodes as well as the physical nodes that act as the border between the substrate network and the external networks.
The overlay network configuration is computed centrally by the VCN Control Plane and the packet-routing rules are delivered to the compute nodes. The compute nodes use these rules to determine the encapsulation and decapsulation action to take on every packet that goes...