VCN peering is the process of connecting multiple virtual cloud networks (VCNs) so that their resources can communicate using private IP addresses. There are four types of VCN peering: 1 Local VCN peering: This is the process of connecting two VCNs in the same region and tenancy. This type of peering uses local peering gateways (LPGs) in each VCN to establish a logical connection.
Remote VCN peering: This is the process of connecting two VCNs in different regions, either in the same tenancy or different tenancies. This type of peering uses remote peering gateways (RPGs) in each VCN to establish a logical connection.
Peering VCNs in the same region through a dynamic routing gateway (DRG): This is the process of connecting multiple VCNs in the same region and tenancy by attaching them to a common DRG. A DRG is a virtual router that provides a path for private network traffic between your VCN and other networks.
Peering VCNs in different regions through a DRG: This is the process of connecting multiple VCNs in different regions and tenancies by attaching them to a common DRG and using IPSec VPN or FastConnect to connect the DRGs across regions.
Peered VCNs cannot have overlapping CIDRs, as this would cause routing conflicts and ambiguity. Peered VCNs need to have unique CIDRs that do not overlap with each other or with any other network that they need to communicate with1 A VCN peering connection is not a VPN-based connection. A VPN-based connection is a secure and encrypted connection between your on-premises network and your OCI VCN over the public internet by using IPSec VPN or FastConnect. A VPN-based connection requires an internet gateway or a DRG in your VCN and a customer-premises equipment (CPE) device in your on-premises network2 Peered VCNs do not need to be part of the same OCI tenancy, as long as they are in different regions. Remote VCN peering supports cross-tenancy connections, meaning that you can peer a VCN in one tenancy with a VCN in another tenancy, as long as they are subscribed to the same regions and have proper IAM policies to allow peering. Local VCN peering and peering through a DRG only support intra-tenancy connections, meaning that you can only peer VCNs within the same tenancy1