The Content Delivery Network (CDN) is a network of Microsoft Azure data centers distributed around the world. Content from Microsoft Azure Blob storage or Web Apps can be cached in the CDN for a certain period of time, ensuring efficient delivery of Blob storage content: a user is delivered content from the nearest data center when accessing Blob storage. On first access by a user, Azure checks whether the requested data is already available in the CDN location. If this is the case, the data is delivered from that location. If the data is not yet there, it is delivered from the original from Blob storage. A copy is stored in the CDN so that subsequent calls can be served from there.
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