Symptoms

Alibaba Cloud Content Delivery Network (CDN) can be used along with other Alibaba Cloud services, such as Elastic Compute Service (ECS) and Object Storage Service (OSS). CDN nodes are distributed in different regions around the world. Data is transmitted over the Internet between Alibaba Cloud CDN and other Alibaba Cloud services. In this case, how is data transfer billed?

Causes

Data transfer of Alibaba Cloud CDN and other services is billed separately. For more information, see the billing rules for each Alibaba Cloud service.

For example, Customer A activated Alibaba Cloud CDN and OSS to provide downloads of files. If a client requests resources from a CDN node that does not have the corresponding resources cached, the CDN node redirects the request to the specified OSS bucket. In this case, Customer A is charged for the outbound traffic of Alibaba Cloud CDN and the outbound traffic of OSS. The outbound traffic of Alibaba Cloud CDN and OSS is billed separately.
  • When a CDN node retrieves resources from an OSS bucket, data is transmitted from the OSS bucket to the CDN node. In this case, Alibaba Cloud CDN does not charge fees but OSS does.
    Note
    • If the accelerated region is outside mainland China and an OSS bucket is used as the origin server, you are not charged for the data transferred from CDN nodes in the accelerated region to the origin server.
    • If the accelerated region is outside mainland China and an OSS bucket is used as the origin server, you are charged for the data transferred from CDN nodes in mainland China to the origin server.
    • If the accelerated region is in mainland China and an OSS bucket is used as the origin server, you are charged for the data transferred from CDN nodes outside mainland China to the origin server.
  • When the requested resources are already cached on the CDN node, data is transmitted from the CDN node to the client. In this case, OSS does not charge fees but Alibaba Cloud CDN does.
Note Alibaba Cloud offers discounts if you purchase Alibaba Cloud services as a bundle. For example, when you use Alibaba Cloud CDN to accelerate the delivery of resources stored in OSS buckets, the outbound traffic of OSS generated during the back-to-origin process is billed at a discounted price.