This image shows the basic elements for a disaster recovery deployment across two Oracle Cloud Infrastructure regions. Each region has a similar configuration.

• Each region provides a single availability domain with 3 virtual cloud networks (VCN) connected by a local peering gateway. VCNs, and their subnets are shown here with basic information:
  • VCN A: Provides an internet gateway, a network address translation (NAT) gateway, two public subnets and a private subnet.
  • VCN B: Provides a NAT gateway and three private subnets.
  • VCN C (Hub): Provides a dynamic routing gateway (DRG), a NAT gateway, and a single private subnet.
• Cross-region communication and disaster recovery uses the following:
  • Public subnets accessed through internet gateways are secured using a web application firewall (WAF).
  • The customer data center uses FastConnect or a VPN to communicate with the hub VCNs through the DRG. Other systems, such as SAP and AWS, similarly use a VPN to communicate with the hub VCNs through the DRG.
  • Hub VCNs can communicate with each other using a software defined WAN network.
  • Database systems use Data Guard to ensure synchronization and availability.
  • Remote peering gateways allow the VCNs' resources to communicate using private IP addresses without routing the traffic over the internet or through your on-premises network.