This image shows multicloud topology with an Oracle Cloud Infrastructure (OCI) region with 1 availability domain, 2 fault domains and a single virtual cloud network (VCN).

The region provides the following services:

• Oracle Cloud Infrastructure Identity and Access Management
• Oracle Cloud Infrastructure Web Application Firewall (WAF)

The VCN provides the following gateways:

• Internet gateway: Provides communications between public subnets and internet hosts. Internet devices and users communicate with OCI by using application programming interfaces (APIs) over a web application firewall (WAF) and an internet gateway. Supported APIs include drone service API, delivery service API, enclosure API over cellular, and user mobile app API.
• Dynamic routing gateway (DRG): Provides private connectivity between on-premises networks and VCNs by using Site-to-Site VPN or FastConnect. Node pool instances in the private subnet communicate with the database (a MongoDB Atlas Cluster) hosted on Amazon Web Services (AWS) cloud by using the DRG, a site-to-site VPN and a virtual private gateway (VPG) on AWS.
• Service gateway: VCNs communicate with services such as object storage over the Oracle network fabric without traversing the internet.

The VCN includes the following subnets:

• Load balancer public subnet: Provides a primary load balancer in fault domain 1 and a standby load balancer in fault domain 2. The load balancers accept traffic from the internet that comes through the WAF and the internet gateway.
• Instance pool private subnet: Provides instances of the Mosquitto (MQTT) broker, node server, and node subscriber API instances in both fault domain 1 and 2.