A Comprehensive Introduction To Content Delivery Networks

A Comprehensive Introduction To Content Delivery NetworksA CDN, or Content Delivery Network, is a means of distribution that  both large-scale and small-scale websites incorporate into their website’s data transfer structure. This technology allows content, usually website files, to be replicated on various data centers around the world. This is, essentially, a means of caching files close to the visitor’s physical location. For example, when a visitor from Russia accesses a website hosted in the United States, there is a certain amount of latency incurred because of the distance between the networks. However, a CDN would first check to see if the file being accessed was already stored on a data center close to the visitor. If the file was found, it would be transferred from the nearest location and greatly reduce any network latency. In case the file was not found, it would be sent from the main server to a data center, ideally, in Russia. When another visitor from Russia accesses the site, the file would then be found on a data center near them and be delivered much faster.

Common CDN Usages

While most websites only use a CDN for distributing images, there are many different ways to utilize this technology for any small website or large business. These include:

Downloading: Large files are best stored on a CDN. This allows users to download files faster and helps reduce the resource load on the site’s server. Gaming companies will often utilize this to distribute large patches to their users. File hosting websites work in a similar manner to ensure that files are distributed in a timely manner and that they are always available.

Streaming: Streaming audio or video is a very server intensive process and typically uses a CDN to allow server stability. Depending on the provider, content can be streamed through Flash, Silverlight or progressive downloading. However, it is important to note that not all CDN providers offer audio and video streaming.

Static Files: Smaller files, such as CSS files, graphics and javascript scripts are ideal for a CDN. These allow the load of a website’s server to be reduced by offloading the task to the CDN. For instance, image intensive sites will use a CDN for any user downloading or uploading that takes place.

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Common CDN Providers

There are many companies that offer CDN services to clients, but there are some that stand out in the crowd. The following providers have revolutionized the industry with their unique approaches:

A Comprehensive Introduction To Content Delivery Networks



Akamai: Akami is the leader in CDN technology. Estimates project that Akami is responsible for 15 – 30 percent of the web’s traffic. Every second of the day, they transfer 4 terabits of data per second. Adobe, MetaCafe, MTV and a slew of others trust Akami with their transfer needs.

A Comprehensive Introduction To Content Delivery Networks






Amazon CloudFront: Amazon is one of the pioneers in the cloud hosting community. With their emergence into the industry, they offered numerous solutions to their clients. Amazon CloudFront is their CDN solution that offers a pay as you use service. This allows small websites to accelerate their websites for a very minimal cost and no commitment.

A Comprehensive Introduction To Content Delivery Networks






CloudFlare: CloudFlare is a hybrid provider that offers many different pricing levels. Their first tier solution is completely free and includes fast site performance, security protection and statistics about your site’s visitors. High solutions include faster speeds, customization and further security enhancements.

A Comprehensive Introduction To Content Delivery Networks




MaxCDN: MaxCDN serves static files through their CDN solution. They offer a pay as you go solution for any data transferred over 1 terabyte. Their fee covers the first 1,000 gigabytes of data, within a 12 month period, which is more than sufficient for most small to medium websites.


Sites Utilizing CDN Technology

Virtually all of the major websites on the Internet utilize a CDN. Some sites have their own data centers and have incorporated the technology on their own infrastructure, while others use one of the many CDN providers available. Facebook, currently the 2nd most visited site in the world, utilizes Akami’s CDN to deliver its massive amount of images to visitors. Twitter, Netflix, Blizzard Entertainment and Yahoo!, among many others, all utilize Akami’s CDN network for both audio and video streaming and static file transfer needs.

Small Website Benefits

Small websites, unlike before, are now able to use CDN providers for their site’s files. While the pay as you go pricing model is becoming popular, virtually any site can now deliver their content with ease. Small websites greatly benefit by using a CDN because it lets them easily scale as their site grows larger. Since the resource load on the server is offloaded to the CDN provider, servers can then be utilized for database communications, server scripts and serving up information on the website.

Large Website Benefits

While some large websites use their resources for their own CDN system, many still use a CDN provider for their content delivery needs. This reduces the cost of having to run servers and maintain them. Since the speed of their content delivery is extremely important to their visitors, it is always beneficial to offer up content through this means. Beyond the obvious benefits, their scaling needs are always met because CDN providers ensure that they have enough resources to handle the largest spikes in data.

Website Performance Optimization

The greatest benefit of using this kind of solution is the site performance gains. Statistics from a Stack Overflow performance test state that using a content delivery network can improve file transfer speeds by 100 – 500 percent. While these numbers vary between providers, a site’s loading speed is greatly increased with any provider. Kissmetrics, a visitor analytic developer, states that 47 percent of consumers expect a page to load in 2 seconds. If a site takes 3 seconds or longer to load, 40 percent of people will leave the site. The speed increase offered with a content delivery network can mean the difference between 40 percent of customers leaving, or the potential of them contributing to your bottom line.

My Experience With CDN Technology

Being a web developer has allowed me to experience the speed increases offered by a CDN. For instance, one of my websites is user based and allows visitors to upload pictures. I utilized Amazon S3 and CloudFront’s API functionality to automatically upload the content to their servers. This allowed me to scale my site and only pay for data storage and transfers. The price comparison between using Amazon and my provider’s normal transfer costs were negligible. While my site loaded in 2.8 seconds before, it now loads in 1.4 seconds. This 50% decrease in loading time fluctuates depending on the visitor’s location, but has helped my site lower its bounce rate and increase visitor pageviews by 100 percent.

Content delivery networks are an easy way to increase a website visitor’s retention and enhance the user experience of your site. Every website, big or small, can utilize this type of service to serve their static files, large files or streaming data. The many available providers allow for an easy and cost effective way for sites to use this type of service and are the backbone for some of the largest businesses in the world.  The decreased loading time lowers the bounce rate, which allows visitors to indulge in the content, products or services you provide.