Content Delivery Networks and why you should use them

DevToolsGuy / Wednesday, January 28, 2015

Over the last ten years or so we’ve seen a considerable growth in the use of Content Delivery Networks (CDNs) making fast access to pages possible for even small websites. By redistributing content to data centers closer to users around the world, download times and bandwidth are reduced, cutting downtime and providing a more streamlined user experience.

Although there are some free CDNs, in most cases you’ll be paying for access to a provider for use of their service. There’s a host of CDN providers out there, so knowing which one is for you, what questions to consider when looking to buy and whether you even need to use one are big considerations.

There are a number of reasons why you might want to use a CDN to redistribute your content. When you ask them to deliver your content, CDN providers then host it on different servers around the world, reducing access times to your pages for end users. For you, this means the costs associated with maintaining servers are reduced, and for end users, access to your web pages and content is much smoother and latency reduced.

CDNs are designed to account for the distance of end users from the server. By caching content in servers geographically closer to them, customers can view a ‘copy’ of your web page, which means the pressure on the main server is reduced. Algorithms calculate where the closest ‘node’ in the network is to the user and take costs and time to download into account before assigning a page to the user.

This is all very well, but you might want to think about whether your website would actually benefit from using a CDN. A general rule is that pages receiving over one million hits per day should think about using one - otherwise they may not be cost efficient. You also need to think about geography; if the vast majority of visitors to your pages are local, you don’t really need to worry about improving access for users the other side of the planet. Further, despite their uses, CDNs aren’t magic bullets for speeding up your page - you also need to think about user optimisation and other methods for improving load times.

For those in the Microsoft universe, their Azure platform is the first point of call for developers thinking about CDNs, so we’ll be paying special attention to it with this post.

What can CDN do for me?

We’ve already looked at why CDN is able to improve accessibility to your content by reducing latency, page load times and bandwidth. Speedy access to your pages is undoubtedly the main reasons you would think about investing in a CDN, but there are a number of other benefits which make them attractive.


  • Most scripts and frameworks are supported by CDNs
  • The majority of time spent downloading a web page is used in downloading elements - CDNs redistribute sources so end users can carry out multiple downloads at the same time
  • If your website has a lot of images and video, CDNs will speed up page viewing time
  • They improve page load times from mobile devices and tablets
  • CDNs can reduce the threat of attacks because they spread risk - hackers would have to infiltrate numerous servers in datacentres around the globe
  • Because your content is redistributed widely, availability of content is almost 100% guaranteed, even in the case of a massive power outage

Cote d’Azure

For those of us working in the Microsoft universe, the Azure CDN is pretty compelling. Launched in 2010, Azure is a cloud computing platform with a truly global reach. Microsoft are the first multinational cloud provider with a datacentre in mainland China, for example, and they have servers in locations around the planet, and serious plans for expansion.

This global reach makes them a major player in the CDN market and allows 24/7 tech support and guaranteed availability, an appealing offer for websites with an international outlook.

The Azure CDN can take advantage of the largest virtual machine in the cloud, a hybrid approach to cloud computing and a unified service provision. What this means for you is a joined-up approach for your business with both Infrastructure as a Service and Platform as a Service combined. As a result, your websites and media should always be accessible for customers.

Microsoft want to be as universal as possible. Azure allows developers to build solutions in almost any language and lets them develop for any browser, client or device while providing Windows and Linux support. It’s becoming the standard for services to be available in the cloud, and with Azure, Microsoft are really taking this to the next level, with practically all aspects of content delivery now done almost exclusively through this platform. Check out how it lines up with other cloud operators here.

Choosing the right CDN

Making use of a CDN can really help with speedy access to your website and deal with moments where you have big spikes in traffic. Deciding which provider is good for you depends on your business needs and target market, so knowing the right questions to ask when looking for a CDN is essential - see this article for some important considerations.

For developers working in the Microsoft universe, the Azure CDN will leap out as the most obvious solution. Not only is it the most straightforward choice being compatible with the Microsoft stack, it’s also hugely powerful.