When a person enters a domain name into the browser or requests information from a Web site, that request is normally routed through a series of servers until it reaches the server where the Web site is housed. The longer the distance the request must travel, the more time it takes to reach its destination. The same rule applies to the information that is returned to the user in response to the request.
The Shortest Distance
A content delivery network streamlines this process by shortening the distance the request and data must travel. With a content delivery network, groups of servers are deployed over a large geographic area. The CDN replicates its clients' data and stores it at each location. When a request comes in, the CDN servers work together to identify the quickest route to transmit the data to the end-user.
Because CDN servers are spread out geographically and over the Internet, they also ensure clients better reliability because they are not affected by a slowdown or outage in one area. A CDN can reroute date through the next-quickest route to ensure delivery to the end-user.