This image shows an Oracle Cloud Infrastructure (OCI) region and a disaster recovery (DR) region with a similar topology. The production region provides 2 availability domains and a single production VCN. The regions are connected by remote peering and Oracle Cloud Infrastructure Full Stack Disaster Recovery Service.

The regions provides the following services (exceptions noted):

Oracle Analytics Cloud
Oracle Cloud Infrastructure AI Services
Oracle Cloud Infrastructure Audit
Oracle Cloud Infrastructure Data Integration
Oracle Cloud Infrastructure Identity and Access Management
Oracle Cloud Infrastructure Monitoring
Oracle Cloud Infrastructure Object Storage
Oracle Cloud Infrastructure Registry
Oracle Cloud Infrastructure Resource Manager
Oracle Cloud Infrastructure Streaming
Oracle Data Safe (production region only)
Ansible
Policies
Terraform

A single virtual cloud network (VCN) provides the following gateways:

Dynamic routing gateway (DRG): Provides private connectivity between on-premises networks and VCNs by using Site-to-Site VPN or FastConnect. A DRG can also route traffic between VCNs for remote peering.
Service gateway: VCNs communicate with services such as object storage over the Oracle network fabric without traversing the internet.
Remote Peering: Allows subnet resources in different regions to communicate using private IP addresses without routing the traffic over the internet or through your on-premises network.

Point-of-sale (POS) systems located at retail locations connect privately by using the VPN or OCI FastConnect. Each VCN is segmented into application and database subnets. Retailers connect to the production VCN by using the DRG.

The production VCN provides three subnets:

Proxy subnet: HAProxy provides load balancing, high availability, and reverse proxy capabilities for the architecture.
Application subnet: Provides an Oracle Cloud Infrastructure Container Engine for Kubernetes cluster with includes instances for merchandising management, store operations, point-of-sale (POS), applications, and business intelligence (BI) in availability domain 1. In availability domain 2, it includes instances for purchasing, cash management, receiving, replication, inventory, and retail analytical platform (RAP). The cluster is replicated to the DR region.
Database subnet: Provides instances for Oracle Autonomous Database, APEX Service, transparent data encryption (TDE), and multitenant container database (CDB)/pluggable database (PDB). The database in the production and DR regions are connected by Oracle Autonomous Data Guard.