The image shows a non-OCI clouds region, an on-premises region, and two OCI regions. Each of the OCI regions contains a VCN with public and private subnets which connect to each other.

The non-OCI region contains applications that connect, via the Internet, to a flexible load balancer in the OCI region, which connects to applications (virtual machine and container) in the public subnet.

The on-premises region connects to the OCI region via site-to-site VPN, or Oracle Cloud Infrastructure FastConnect. A dynamic routing gateway within the OCI region connects to high-availability Oracle MySQL Database Service systems in the private subnet.

Both of the OCI regions contain a dynamic routing gateway that interconnects the two OCI regions together. Within one of the OCI regions, the Oracle MySQL Database Service systems high-availability cluster acts as the primary transactional database with managed read replica scalable up to 18 replicas for read workload and a self-managed replica in another OCI region for disaster recovery and backup purposes.