Content Delivery Network (CDN)

Content Delivery Network (CDN)

A Content Delivery Network or CDN is becoming more common place. Since there are some providers that offer free services there really is no reason not to give them a try.

What is a Content Delivery Network and why should I use one?

A CDN is basically a distributed set of cache proxy servers generally spread around the globe. What they do is keep copies of common static content from your website. Examples would be your logo and any images your have on each page. Dynamic or changing content will not be cached, so if your website is largely dynamic in nature it is questionable as to whether you will get any performance benefits.

The way a CDN works from the visitors perspective is they first connect to the CDN network that you have configured. Whatever content that has already been stored in the CDNs servers will be delivered to the visitors computer. If anything is missing from the page it will then retrieve it from the web server. This can speed things up dramatically if there is a great distance between the visitor and the web server, say the visitor is in the UK and the web server is in the US. This is assuming of course the CDN has servers in or close to the UK.

What is a CDN?

A simplified view of a Content Delivery Network in relation to the web server

Do they have other Benefits?

Another benefit of a CDN is they can defend against DDOS (Distributed Denial of Server) attacks which are unfortunately getting more common. What these attacks do is overload your web server by send too many requests to it. A CDN can assist by taking the brunt of the attack before it gets to your server. CDN providers like Cloudflare actually advertise this as a feature of their service.

Who uses them?

CDNs are commonly used by sites that have global reach and need content to be delivered fast. Probably the biggest user of a CDN at the moment is Netflix who operated their own system. Youtube also use CDNs to cache videos close to the viewers.

Where’s a good place to start

Probably the most common provider that comes up these days is Cloudflare. This is probably due to their entry level free offering combined with its ease of use.  It really doesn’t take much to configure it because Cloudflare will analyse you existing DNS (Domain Name System) and import the records over to Cloudflares DNS.  You then change your DNS records to point to Cloudflares DNS servers instead of your current ones and that’s it.

Are there alternatives?

As with most things in life there are alternatives, both free and paid. Some of these are as follows:

Free

SwarmCDN – They privide a free plan however unlike Cloudflare the traffic is capped.
Coral CDN – A P2P (Peer to Peer CDN). Think Bittorrent for websites.

Paid

MaxCDN – A popular paid CDN
Incapsula – Security focussed DNS with DDOS protection
Rackspace – A cloud services company that also offers a CDN
Amazon AWS – Amazon offers a CDN a part of their large cloud services platform.

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