The OCI region includes 1 virtual cloud network (VCN) that spans 2 fault domains. The VCN includes the following gateways:

• Internet gateway: Provides communications between public subnets and internet hosts.
• Dynamic routing gateway (DRG): Provides private connectivity between on-premises networks and VCNs by using Site-to-Site VPN connected to the DRG. In this case, data source systems from on-premises or third-party cloud systems access OCI through the DRG. Similarly, target systems in public clouds, private clouds, or on premises access OCI through the DRG.

The VCN provides 3 subnets:

• DMZ public subnet: Incoming traffic is handled by a load balancer. Web node, Collaborator, Publisher, and file storage resources are provided in one fault domain. Web node and Publisher resources are provided in the other fault domain.
• APP private subnet: Virtual machine (VM) instances provide data integration and migration, data cataloging, bots, analytics and visualization, app building, caching, scheduling, and master data management (MDM) in each fault domain.
• CB private subnet: Provides active PostgreSQL instances in one fault domain and standby instances in the other fault domain for Meta DB, Datamart, Solr1, Couch DB2 database instances.