It is useful as a media server, but a CDN is a lot more. "CDN nodes are deployed in multiple locations, often over multiple backbones. These nodes cooperate wi

It is useful as a media server, but a CDN is a lot more. "CDN nodes are deployed in multiple locations, often over multiple backbones. These nodes cooperate with each other to satisfy requests for content by end users, transparently moving content to optimize the delivery process. Optimization can take the form of reducing bandwidth costs, improving end-user performance, or increasing global availability of content. The number of nodes and servers making up a CDN varies, depending on the architecture, some reaching thousands of nodes with tens of thousands of servers. Requests for content are algorithmically directed to nodes that are optimal in some way. When optimizing for performance, locations that are best for serving content to the user may be chosen. This may be measured by choosing locations that are the fewest hops or fewest number of network seconds away from the requesting client, so as to optimize delivery across local networks. When optimizing for cost, locations that are least expensive may be chosen instead. Often these two goals tend to align, as servers that are close to the end user sometimes have an advantage in serving costs, perhaps because they are located within the same network as the end user. However the value of a CDN is often demonstrated when these two goals do not align i.e. when the best performing servers and network route is located in the furthest geographic distance."