Overview

VPCs are isolated from each other. To connect two VPCs in the same region, you can use a VPC peering connection to route traffic between them using private IP addresses.

Here are some scenarios to help you determine which configuration is best suited to your networking requirements.

**Table 1** VPC peering scenarios
Scenario	Configuration Description
VPC CIDR blocks do not overlap. Subnet CIDR blocks do not overlap.	Create VPC peering connections to connect entire CIDR blocks of VPCs. For details, see Connecting Entire CIDR Blocks of VPCs.
VPC CIDR blocks overlap. Some subnet CIDR blocks overlap.	Create VPC peering connections to connect specific subnets or ECSs from different VPCs. To connect specific subnets from two VPCs, the subnet CIDR blocks cannot overlap. For details, see Connecting Specific Subnets from Different VPCs. To connect specific ECSs from two VPCs, each ECS must have a unique private IP address. For details, see Connecting Specific ECSs from Different VPCs.
VPC CIDR blocks overlap. All subnet CIDR blocks overlap.	VPC peering connections are not usable. For details, see Unsupported VPC Peering Configurations.