Limitations of VPC peering connection are:
- You cannot create a peering connection between VPCs with an overlapping CIDR range.
- You cannot create VPC peering between VPCs in different regions.
- Peering does not support unicast reverse path forwarding.
- Peering is not transitive. This means, if you have peering between VPC A and B, and you also have another peering between A and C, A and C cannot talk to each other.