Why use a Content Delivery Network (CDN)?

Content Delivery Networks (CDN) have been around for a few years now and are used by most major websites – yet the normal website user won’t be aware of this.  Just what are CDNs?

CDNs are alternative servers to the main website, which can be used to store files and assets.  The majority use of CDNs are the storage of “static” files  – images, CSS and JavaScript files.  They are commonly quoted as being hosted in “The Cloud”, that nebulous collection of servers with no single physical location.  They are primed and ready to deliver content to the website user on demand.

So what’s the difference between a CDN and storing files on a web server? 

Files are distributed amongst many servers in The Cloud, at different geographical locations and backed-up multiple times.  There is no single point of storage, the files do not live on a single hard drive but populated amongst The Cloud.

What are the advantages to using a CDN above traditional website hosting?

How a website browser such as Chrome, Firefox and Safari work is by downloading information from a website piece by piece.  Each piece is usually something unique – an image, script file or CSS reference.  However a website browser will only attempt to download so many pieces at one time.  So you may have the fastest internet connection and the best website server, but browsers will only download some many pieces at once from a single location.  This is called Concurrency.

If you are using a CDN, some pieces are served from a different location – using a special CDN dynamic address.  The beauty of this is that website browsers will download pieces from your CDN in parallel to downloads from the website servers.  Therefore much more of your website is downloaded in any given timeframe.

As an analogy – if you have one central location from which your website is served, it is like having a single-lane road.  No matter how fast the lane is, only so many cars can fit into it.  With a CDN, you have converted your road into a dual carriageway or motorway, so 2 or 3 times as many cars can travel on your road.

There are additional benefits too – CDNs will serve assets from the closest Cloud server to the user, great for websites with a large international user base.  They also have great caching functions, which prevent browsers having to download the same file multiple times.

How does this help me get more business  from my website?

Simply put – the quicker that your website loads, the less chance that users will leave your site and the more chance they have of making a transaction or final contact.  Many studies have shown that there is a direct relationship between the speed of a website and the amount of business it generates.

How much does it cost?  What are the limits?

Cloud hosting is extremely cost effective when compared to hosting on web servers with physical hard drives or solid-state drives.  Whilst costs vary between different providers, we have seen accounts with 120GBs of storage being charged around $10 p/m.  Everything is on a cost-per-use basis – you only pay for the storage space you use and the bandwidth it consumes serving the content.

There are no limits to what you can do with CDNs.  Whereas with a normal web server, once you fill the hard drive with images and content, your only solution is to upgrade the hard drive or get a new server.  No matter how big or busy your site gets, CDNs are both scalable (you have as much resource as you need) and burstable (there are no limits on the overall speeds information is sent to users, regardless of how many requests are being made at any one time).

Is this only for website images and files?

No.  Anything that can be stored on a web server can be stored on a CDN.  Databases, backups, network files, archives, personal files and many more types of information can be stored on a CDN.  There are also a wide range of technologies which integrate with CDNs – Opencart, WordPress and Cpanel all have seamless integration options.

I don’t like the idea of not having a physical copy of my files.

We understand this.  But so much of 21st Century Internet life is in The Cloud.  Your GMail, iCloud or Hotmail account, your Facebook and Twitter account, Netflix, your Dropbox, Google Drive or We Transfer files, your Internet Banking – they are all stored not on one central location but in The Cloud.  Your website is probably no different, it will be hosted on a server with other servers in a dedicated building somewhere in the UK, but it’s not really any more tangible than having it in The Cloud.

Cloud hosting is far more reliable than single point storage on magnetic devices.  A single hard drive can fail, be damaged or simply go missing.  Amazon, the lead provider of CDN and Cloud storage, guarantee that on average they will lose one file every 10 million years.

You can keep files on a local or web server as well as in The Cloud if you wish and simply take advantage of the speed.  We however think that’s slightly missing the point and are looking to move more of our client’s assets to The Cloud in order to get better returns for their websites.