This image shows a hub-and-spoke architecture with an on-premises data center which connects to an OCI Region using site-to-site VPN or FastConnect through a DRG.

The OCI Region hosts three tenancies/VCNs and the DRG directs traffic using DRG attachments to each of the three VCNs:

• DRG attachment A directs to VCN A which hosts a virtual machine.
• The next DRG attachment directs to the Central VCN which hosts a firewall virtual appliance.
• DRG attachment B directs to VCN B which hosts a virtual machine.