I have an ECS cluster of services running on a few EC2 machines. Each service is internet facing and forms a target group, all these target groups are on the same load balancer.
Architecture: Service 1 -> TG1 -> ELB Service 2 -> TG2 -> ELB ELB Rules: If request from 1.domain.com -> route to Service 1 If request from 2.domain.com -> route to Service 2
The services communicate with one another via their public CNAMEs.
I'm trying to figure out data-out transfer costs when Service 1 communicates with Service 2 by calling an endpoint on 2.domain.com. I think we'd be charged at the same rate as data-out to public internet even though the services are in the same region (could literally be hosted on the same machine), as the communication doesn't happen through a private IP but through the public internet. I've consulted the AWS documentation and can't find anything related to confirm this. Can someone help with this please?
Edited to Add: My AWS bill reflects data out charges because we use several public services and we provide information to clients outside the network. I want to know if this specific case is charged as well.