Question

Your company uses Network Connectivity Center with a single hub to interconnect four VPCs as VPC spokes for full-mesh transitive connectivity. You attempt to attach a fifth VPC as a spoke, but the operation fails. Investigation shows this new VPC contains a subnet with the CIDR range 10.20.0.0/24, which is identical to a subnet already present in one of the existing spoke VPCs. What is the most appropriate action to successfully attach the fifth VPC as a spoke?

Accepted Answer

Re-IP the overlapping subnet in the fifth VPC to a non-overlapping range before attaching it as a spoke, because NCC VPC spokes require unique subnet ranges across all spokes on the hub.

Answer

Enable the 'export custom routes' setting on the hub so that overlapping ranges are automatically deduplicated during spoke attachment.

Answer

Attach the fifth VPC using a group with the 'auto_accept' policy, which allows overlapping subnets by installing longest-prefix-match routes.

Answer

Create a Cloud Router in the fifth VPC and use custom route priorities (MED) so the overlapping subnet is preferred only within its own VPC.