The image shows the physical architecture of an OCI deployment in Region 1 with Region 2 as the failover region. Input is received from enterprise applications located on-premises and from internet users.

Each region has the following:

Hub VCN with an Oracle Cloud Infrastructure Web Application Firewall (OCI WAF) and a public subnet (Application). The public subnet (Region 1: 192.0.2.1/28 and Region 2: 192.0.3.1/28) has a public load balancer and a standby load balancer.
The subnet has an internet gateway, service gateway, and dynamic routing gateway (DRG). The DRG links to the back-end tier.
JSON Workload VCN with a private subnet (back-end tier) and a private subnet (Database tier). The private subnet back-end tier (Region 1: 10.1.10.1/28 and Region 2: 10.2.10.1/28) has an Instance Pool with two application servers. The private subnet database tier (Region 1: 10.1.20.1/28 and Region 2: 10.2.20.1/28) has the MongoDB API for Oracle Autonomous Transaction Processing Serverless. Oracle Autonomous Data Guard region peering link the databases in OCI Region 1 and OCI Region 2.
The subnet has a DRG, a NAT gateway, and a service gateway. Remote peering links the DRGs in OCI Region 1 and OCI Region 2.
Oracle Services that include OCI Object Storage and OCI Full Stack Disaster Recovery. Disaster Recovery actions link the services in OCI Region 1 and OCI Region 2.