A content delivery network (CDN) is a network of distributed servers used to deliver content to end users quickly and efficiently. The content of a website, such as images, videos, stylesheets or JavaScript files, is stored redundantly on several servers worldwide and delivered to the end user from the nearest server.
How does a CDN work?
A CDN consists of so-called edge servers that are distributed around the globe. When a user calls up a website that uses a CDN, the request is forwarded to the nearest edge server to keep latency (delay) as low as possible. The edge server then checks whether the requested content is already stored in the local cache. If it is, the content is delivered directly to the user. Otherwise, the edge server fetches the content from the origin server and stores a copy in the local cache before delivering it to the user.
Advantages of a CDN
- Faster loading times: Delivering content over a globally distributed network can significantly reduce load times by delivering content from the nearest server instead of the central origin server.
- Scalability: CDNs are able to absorb peak loads and dynamically increase bandwidth to meet the demands of high user traffic. In many cases, this protects against overload and outages of the origin server.
- Reduced server load: Since a majority of the requests are answered by the CDN's edge servers, the load on the origin server is reduced, resulting in better performance and stability.
- Increased safety: CDNs provide additional security features such as DDoS protection and SSL offloading to protect the website from a variety of threats.
Relevance of CDN in online marketing
CDNs are relevant for online marketing for several reasons. One of them is that fast loading times ensure a positive user experience, which improves both the conversion rate and the ranking in search results. In addition, search engines like Google use load time as a ranking factor, so a fast-loading website ensures better visibility in search results.
