What Is a Content Delivery Network? All You Need to Know

globe next to it it says: what is a content delivery network? all you need to know

In the age of Google and search engine optimization (SEO) marketing, you won’t come around the question “What is a content delivery network (CDN)?” very often.

A content delivery network is a geographically distributed network that consists of a number of interconnected servers and their data centers. Companies use it for a fast, reliable and secure delivery of website content.

Statistics show that over 41% of the top 10.000 websites rely on a content delivery network to ensure a qualitatively high and fast performance of their sites.

This should come as no surprise considering the significant impact loading speed has on the conversion rate of a site. A study has shown that websites who achieve the highest number of revenue have a page loading speed that is around 26% higher than that of other websites.

To fully understand what content delivery network is as well as its advantages, we’ll have to dig a little deeper and take a look at the complexities of its operating modes, the different shapes and forms it comes in and the variety of advantages they give.

Here’s a list of questions addressed in this article in case you’re interested in sneaking a peek:

  1. How Does a Content Delivery Network Work?
  2. What Is the Purpose of a Content Delivery Network?
  3. Why Do Online Businesses Need a Content Delivery Network?
  4. What Are the Advantages of Using a Content Delivery Network?
  5. How Do You Implement a Content Delivery Network?
  6. How Much Does a Content Delivery Network Cost?

How Does a Content Delivery Network Work?

world map with content delivery networks around the globe

To be able to answer the “What is content delivery network?” question, we first have to make sense of how it works.

When a user tries to access a piece of website content – say, for example, a certain item put up for sale on an ecommerce site – it is of great importance that the data delivery from the website owner’s server to the end user is done as fast and smooth as possible. And it goes without saying that fast delivery should be guaranteed regardless of the end user’s location. In a nutshell, that’s what content delivery networks are for.

However, to be able to grasp how this is achieved, we have to ask ourselves: “What is content delivery network made of?”

To begin with, a content delivery network has an origin server. The data to be distributed is stored on this server.

Next, there are data centers that are spread around the globe covering multiple locations. These data centers carry copies of the original data as a way of enhancing security and preventing the occurrence of system failures by, for example, frequent user activities.

Moreover, a content delivery network provider will place proxy servers at so-called internet exchange points (IXPs). IXPs are exchange points between different internet providers that allow a content delivery network provider to offer high speed data delivery and lower costs to its customers.

As for the redirection of user demands to the content delivery network, a request-routing system takes care of that aspect. It chooses the most suitable proxy server by assessing the level of the current CPU load and the network connection between the querying system and the server, among other things.

What Is the Purpose of a Content Delivery Network?

on the left content reaching users without a content delivery network and on the right with

To further elaborate on what is content delivery network, it is important to highlight its twofold purpose. On one hand, there’s a content-oriented content delivery network function and on the other, a security-oriented one.

Content-Oriented Content Delivery Networks

To understand what a content delivery network is, you should first and foremost bear in mind that the primary purpose of a content delivery network is, as the name implies, to deliver content.

Over time, this process has evolved, making automated data exchanges possible. For instance, the function of origin pulling was introduced, which allowed for users to request a content delivery network’s URL.

This triggered an automatic URL request sent by the content delivery network to the origin website. This enabled the content delivery network to cache every data it received from the origin server and make it available for the user.

On top of this, many content delivery networks cache the most up-to-date version of a website’s content to ensure it’s availability even in case the origin website is down. They also often optimize the data they’re delivering by for example resizing the images of a website to shorten the loading time of a site.

Security-Oriented Content Delivery Networks

Another very important and, surely, much appreciated functionality of content delivery networks is DDoS (distributed denial of service) and bot protection.

A content delivery network is seen as the external layer of a website, which puts it on the front line of receiving traffic. That’s why it’s within its competencies to detect security threats and ideally eliminate them before they even reach the origin server.

What’s more is that a content delivery network has the ability to gather important information from its clients which will allow it to learn and be able to detect spams, fishy IP addresses and much more and stop their distribution to other servers.

Why Do Online Businesses Need a Content Delivery Network?

  • Speed: For one, since content delivery network providers let content go through the node closest to the end user instead of letting it go through multiple nodes, your customers will benefit from faster loading times and less bandwidth usage. Another thing is that content delivery being their specialty, such providers will offer optimization of your content delivery through:
    • File compression
    • Code minimization
    • Image optimization
  • Security: As already mentioned, content delivery networks can also serve as a protection layer that prevents security breaches from reaching you, provided that you keep security-sensitive data, such as passwords, away from them.
  • Wider reach: Most online businesses don’t just settle for targeting customers in one region. To expand their revenue they will want to expand their reach and make their products and services available in as many countries as possible. For this they’ll need a content delivery network that offers them data centers in multiple locations.
  • Elasticity: The thing about offering your goods and services globally is that sometimes it’s hard to anticipate the traffic inflow and the amount of simultaneous activities on your website. By distributing your traffic inflow to multiple proxy servers, content delivery networks enable you to balance big inflows of traffic and avoid a server overload.

What Are the Advantages of Using a Content Delivery Network?

Globe surrounded by 3 servers

  • For the website owners who tend to have a fluctuating traffic inflow, content delivery networks allow for an optimized load distribution across the globe.
  • Content delivery networks reduce the amount of bits that have to be delivered. Website content is compressed to ensure low latency. If you want to test your page speed, make sure to visit our WordPress Speed Optimization page. It allows you to check your page speed score and get an optimized copy of your website with just one click.
  • Additionally, content is bundled in data packages and delivered in a collective unit. Why? Because providing content individually upon every single request would increase processing time.
  • As already elaborated, content delivery networks store content at data centers located closest to the end user. This process is also known as caching or streaming and concerns static content, i.e. content with the least likelihood to change. Copies of static content are outsourced via content delivery networks to differently located nodes, making data delivery to the end user even faster.
  • When it comes to dynamic content, it can’t be simply cached because of its ever-changing and user-specific nature. This type of content has to be transferred by the host him- or herself, which prolongs the data delivery time. Add to that the fact that transmission control protocols (TCPs) aren’t trimmed for speed. But even this kind of TCP data flow is optimized by content delivery networks, always using the fastest routing paths to deliver content in its dynamic form and in real time.
  • Content delivery networks are designed to learn from user behavior. In this vein, algorithms are used to anticipate the next user decision with the highest likelihood of occurring. Based on these calculations website content is delivered before the user even requests it. This significantly reduces latency and is especially useful for online businesses that want to avoid losing customers due to long loading times.

How Do You Implement a Content Delivery Network?

The implementation process varies from provider to provider. But the basics are, roughly speaking, similar.

The content delivery network is implemented in such a way that the URL given to you by your content delivery network provider directly refers to your website. Via CNAME entries you have the possibility to also use subdomains.

For instance you can do this at CloudFlare. You only have to register with an email address, after which you’ll be asked to indicate your site domain so that they know from where to extract the data. Next you can choose a plan and create a CNAME, if needed.

Once you have successfully set up a content delivery network and have your new URL, you can implement the content delivery network on your WordPress website.

You can do so by using plugins such as Autoptimize or W3-Total-Cache. You simply have to enter your content delivery network URL and everything else will take off by itself.

Once you’re done filling out the cache settings, make sure to clear caches. After that the content delivery network provider will create the respective cache data once the website is called up.

From this moment on, everything is set. Don’t forget to check out the settings offered by your provider in case there are any useful optimization services, for example.

How Much Does a Content Delivery Network Cost?

dollar bills, on it a piggy bank

There’s a growing number of content delivery network providers. You have the option of choosing a free version for small websites, but you can also go for some premium offers tailored around the needs of bigger clients. Your decision should depend on your budget and your technical expertise.

For some free options, make sure to check out the following providers:

  • Google App Engine: This option, while free of charge, sets some limits to the services provided. For small or medium-sized websites this should be enough. However, note that the implementation process is rather complex given that you’ll have to upload your data to Google’s server manually.
  • CloudFlare: With CloudFlare, users can register their domain for free and distribute their content to more than 20 different data centers around the globe. The provider has no limitations in the free tariff. However, if you’re in need of optimization or security services, you’ll have the option to upgrade to the premium plan.

For those of you who have the necessary financial resources, here are two popular options for you:

  • Akamai: Akamai is one of the most popular providers to date. It’s especially suitable for website owners who require a more extensive reach. It provides more than 80 data centers. Akamai stands out in particular when it comes to speed and flexibility.
  • Amazon CloudFront: Also one of the most known providers is Amazon with its CloudFront content delivery network. Amazon’s services are particularly known for their reliability. What’s more is that Amazon CloudFront is more user-friendly when it comes to the implementation process. Plus, the costs are kept within reasonable limits. Request costs lie somewhere between $0.0075 – $0.022 per 10k requests.

So, this was our long answer to the short question “What is content delivery network?” Let us know about your experiences with content delivery networks and which providers you would especially like to recommend… We’re all ears!

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