AWS Certified Advanced Networking Specialty Practice Exam

Who bears the cost for data transfer when accessing an Amazon S3 bucket owned by another organization using a public Virtual Interface (VIF)?

1. The on-premises organization

2. The AWS account owning the VPC

3. The Amazon S3 bucket owner

4. The user requesting the data

The correct answer is: The Amazon S3 bucket owner

When accessing an Amazon S3 bucket owned by another organization through a public Virtual Interface (VIF), the cost for data transfer is borne by the Amazon S3 bucket owner. This principle is based on the AWS pricing model, where the owner of the resources (in this case, the S3 bucket) incurs costs related to data transfer out from AWS to the internet or other destinations. The VIF itself enables the connection between on-premises networks and AWS services, allowing for efficient data transfer. However, when the data is retrieved from the S3 bucket, the owner of that bucket is responsible for the data transfer costs associated with sending that data out, regardless of the requester. This approach aligns with other AWS services where the data transfer fees are attributed to the service's resource owner when data is accessed or transmitted. In scenarios involving data access, costs are typically structured such that the resource owner must account for outbound data transfer, as they manage the underlying infrastructure and data storage. This concept is crucial for organizations to understand when accounting for costs associated with using AWS services, especially in cross-account or public access scenarios.