A content delivery network or content distribution network (CDN) is a large distributed system of servers deployed in multiple data centers across the globe. Their real value comes when you think about latency–or the time it takes for your information to be delivered hundreds or thousands of miles away from your actual web server.
Besides offering better performance and availability, CDNs also offload the traffic served directly from the content provider’s origin infrastructure.
Last, but not least, CDNs provide a degree of protection from Denial of Service (DoS) attacks by using their large distributed server infrastructure to absorb the attack traffic.
How a CDN Works
Here’s a video by our friends at MaxCDN that explains the value of CDNs and how they can help speed up your website.