Cost Structure and Directional Optimization for AWS VPC Peering, TGW, Cloud WAN, and DX

AWS network costs consist of data transfer fees, managed service processing fees, and fixed connection fees. VPC Peering has no fixed costs, but cross-AZ traffic incurs $0.01 per GB on both the sender and receiver sides. Transit Gateway (TGW) incurs a fixed hourly fee per attachment (Seoul $0.07) and processing fees ($0.02/GB), consolidating cross-AZ charges into processing fees to simplify routing. Cloud WAN adds $0.50 per hour per CNE, hourly fees per attachment (Seoul $0.09), and processing fees ($0.02/GB). Inter-region transfer applies rates based on the source region, resulting in a 4x difference: $0.08/GB for Seoul to us-east-1 and $0.02/GB for the reverse direction. While TGW and Cloud WAN add $0.02/GB in processing fees compared to inter-region VPC Peering, they offer management convenience and segment isolation benefits for large-scale connections. For on-premises connectivity, the break-even point between Direct Connect and Site-to-Site VPN is approximately 2.1TB per month for a single port, rising to about 4.6TB with port redundancy. For bulk data replication or backups, it is advantageous to design traffic from us-east-1 to Seoul (based on destination region rates) to leverage lower costs.