Two microservices communicate frequently. One is in a Cloud Storage bucket in us-central1 and the other runs in us-east1; egress costs between the services are high. What design change most reduces inter-region network egress costs?

Moving both the Cloud Storage bucket and the microservice (running on a VM) to the same region, such as us-central1, is the most effective way to reduce inter-region network egress costs. When resources are in the same region, traffic between them is considered intra-region and typically incurs significantly lower or no egress charges compared to inter-region traffic. VPC peering does not eliminate inter-region egress costs; it facilitates private connectivity but charges still apply for traffic crossing regional boundaries. Converting to a multi-region storage class distributes data but doesn't eliminate egress costs when a service in a different region accesses it. Cloud Router is for hybrid connectivity and routing, not for eliminating inter-region egress charges within Google Cloud.