CDN basics: what is content delivery
04 Sep 2015

CDN Basics: What is Content Delivery

Content delivery or distribution is the global process, which covers almost all areas of online business. Millions of users all over the globe get required content by CDNs (content delivery companies) every day. However, most of users even not aware of the existence of CDNs. Meanwhile, content distribution plays a huge role in data exchange improving. What is content delivery network? Generally, it can be described as a system of multiple servers allocated all over the globe to deliver content to users from the short distance. Some delivery companies have dozens of thousands of servers in multiple Pops (points of presence). Each distribution company decides how many Pops it is necessary to build. However, the more Pops company has, the greater the likelihood that it will satisfy users requests effectively. Such authoritative content distribution companies as Amazon CloudFront, CDNsun and CDN77 have 52, 85 and 27 points of presence over the globe, respectively. Usually Pops are distributed through five continents accordingly to customers requests. For example, CloudFront has 20 of their Pops in North America, 16 in Europe and 14 in Asia. CDNsun has 25 Pops in America, 16 in Asia and 44 in Europe. However, some of content distribution companies decide to improve their effectiveness not by the number of Pops, but by improvement of communication channels. Such approach also showed its effectiveness.

Most of content delivery companies use caching principle for their work. This principle can show what is content distribution in a best way. Generally, the mechanism can be described as the popular content preference. Indeed, content delivery servers store only a popular content, which has many requests. At first, any specific content is stored only on the origin server. But then, after the first request from the specific user, such content goes to specific CDN servers, too. That means, that user, which made the first request on a specific content, will take all time costs. For other users from technologically close area load time will improve, because they will already deal with content distribution servers. Every time when request appears, system decides what to do with it. If it has the requested data on delivery servers, request will be satisfied by them. If not – request will be re-forwarded to the origin server. System selects servers due to their technological proximity to users. Usually technological proximity includes such concepts as geographical proximity, available ports and servers speed.

Some answers on question what is content distribution network can be also found in the information about website improvement. In truth, CDN can really help to improve website’s page load time, response time and general effectiveness. However, it is important to do all steps to improve the website before CDN will be set up. In some cases website optimization is the only thing really needed. Especially this applies to small business, which work on a geographically small territory.