A company uses the us-east-1 Region and the ap-south-1 Region for its business units (BUs).

Configure an AWS Cloud WAN network that operates in the required Regions Attach all BU VPCs to the AWS Cloud WAN core network. Update the AWS Cloud WAN segment actions to configure new routes to deny traffic between the different BU segments.

Configure a transit gateway in each Region. Configure peering between the transit gateways. Attach the BU VPCs to the transit gateway in the corresponding Region. Configure the transit gateway and VPC route tables to isolate traffic between BU VPCs.

Configure an AWS Cloud WAN network that operates in the required Regions. Attach all BU VPCs to the AWS Cloud WAN core network. Update the core network policy by setting the isolate-attachments parameter for each segment.

Configure an AWS Cloud WAN network that operates in the required Regions. Create AWS Cloud WAN segments for each BU. Configure VPC attachments for each BU's VPCs to the corresponding BU segment.