Understanding data transfer scenarios

Why do data transfer costs exist? Data transfer costs exist because various network boundaries exist within the AWS ecosystem and there is a cost associated with crossing those network boundaries. You might cross boundaries to get from the AWS network out to the internet, or cross boundaries to get from one AWS Region to another.

Within each AWS Region, there are at least two AZs. Each of these AZs can represent multiple data centers, and each AZ has its own infrastructure, such as power, cooling, and security. They’re connected with redundant ultra-low latency connections and are physically separate from each other. These clusters of AZs constitute a Region and are set apart to protect them from issues such as power outages and natural disasters, but are still close enough to support synchronous replication scenarios for your workloads.

Now, to take advantage of AWS’ global network, you can create a virtual network that spans...