Content Delivery Networks – What, Why and WOW

Map of the world displaying network linksContent Delivery Networks, CDNs, origin push and origin pull…
Has your brain exploded yet? Don’t worry I know things might seem confusing now but let’s work on clearing some of that up. On my recent break from work I delved into the realm of CDNs and found out how impressive the results of using a CDN are in speeding up website page load times, as well as learning a lot of new things along the way which I will share today.

A bit about CDNs

First things first,  a CDN is a distributed network of servers that synchronise content between them. A content delivery network may have upwards of 15 geographical locations where they can serve content from. The important and distinctive feature of a CDN is that when a file is loaded by a customer the CDN will detect and send them to the closest server to get the content. The closer you are to the server the faster it loads. Therefore if two customers, one based in Sydney and one based in New York load the same file they will be sent to two geographically distinct servers greatly reducing the time required to load content.

With that in mind it is time to bust a little bit of jargon. An origin pull CDN defines a solution which does not require content to be loaded onto the CDN manually. By simply replacing the standard hostname with the CDN hostname, the CDN will either:
a) serve the file if it already has it, or
b) if it has never seen the file before (or it has expired) will load the file from you own server (the original hostname), cache it on the CDN servers for future hits and then serve it to the initial person loading it on the fly

The benefits of origin pull are that by simply changing the URL (either manually or programatically) you can easily enable the use of a CDN on a website or other web application for loading all the static content including files such as images, CSS and javascript files. If you have a look at this page you will see the Softlayer logo uses http://cdn[xx] rather than the standard link that WordPress would use ( and this is an example of how W3TotalCache has made it very simple to enable a CDN for this WordPress blog.

The alternative to an origin pull CDN is an origin push CDN which requires you to push/upload content to a storage area on the CDN and then link to the content. The difference between the two solutions is that origin pull is generally better for lots of small files such as Javascript, CSS files, XML and images that would be served as part of a standard blog. Conversely, origin push is required when you will be serving large files such as video, audio and streaming media. With this in mind, in an origin push setting you will also need to rent storage space from the CDN provider to store these larger files where as origin pull will generally only have a per Gigabyte charge.

Softlayer’s CDN

Softlayer LogoSo now with jargon aside, if you are in need of a CDN for your site I would strongly recommend Softlayer. In the coming weeks I will be putting a couple of posts together on issues I ran into, how to get things set up and most importantly how it all works.I can definitely say that once you work out the quirks it is extremely simple to get going (I know, I know… famous last words :D).

I would also like to give a big shoutout to the team at Softlayer for their assistance in helping me get my new CDN set up with them. Softlayer uses the Edgecast Content Delivery Network and has very reasonable prices ($0.12/GB USD), especially when you consider the worldwide coverage (which for me includes a POP here in Sydney).

The team has been extremely helpful in getting me up and running and I give them 12/10 for their support. The only thing I will say is, I feel the website wasn’t clear that the pay as you go option is exactly the same cost per gigabyte as the prepaid option (so keep this in mind, by going with pay as you go you only pay for what you use). Unfortunately once the CDN is set up as a prepaid you can not switch to pay as you go. I have learned this the hard way and have had to set up everything a second time. With that aside, page load times for my sites are through the floor and I am working on tweaking things further as I go. To provide some insight into just how much faster things are I I have reduced the page load time for the Technical Notebook homepage from between nine and ten seconds (outside of the US) down to around three to four seconds from most locations around the world.

For you bloggers out there if you use WordPress (self hosted) I would strongly recommend you consider looking at the possibility of a Content Delivery Network to help speed up your web site loading times around the world, also keep an eye out here on Technical Notebook in the near future for more info).

Hopefully this has been insightful and you might just have learned something new.


Collusion the new iPad stylus – A video of my first experiences

OK so you will have heard a lot about Collusion from me lately. 😀 Why? Because I love the concept and the team from Collusion are a great bunch of blokes. They have also just released the video they took of me from the first Collusion Beta Backers event so I thought I should definitely share it with everyone. Hopefully this will help answer some of the questions that people have been asking me thus far. As always if you have any questions just drop a comment here :).

Also don’t forget to check out my other posts on Collusion. Or if you want check out the official Collusion site, or the Collusion Project on Kickstarter.

Collusion is The iPad Pen to end capacitive “crayons” – What might you like to know?

Image provided by

Many of you who have been poking around Technical Notebook recently will have seen my Initial thoughts on Collusion and then the follow up with Everything I have found out so far about Collusion. As I am lucky enough to be in Sydney, where the guys from Collusion are currently based.  I have been able to see them each Friday night and learn more about the device and what we can expect when it is released.

For those of you that don’t know what Collusion is, I have best heard it described as the iPad Pen to end capacitive “crayon” like input devices for the iPad. I would recommend you check out my above articles and have a look at the official Collusion Site.

What I did want to put out there however is… what do you want to know about it? What are the questions that are burning on your mind that you would love to find out more about? Throw your questions/suggestions at me and I can take them to the guys when I see them next Friday night. While I can’t promise responses for everything flick them over to me (just leave a comment here) and I will see what I can do.

As soon as I know more information I will be back here to give you the latest goss and keep you up to date on what is happening and how things are progressing as we head to the beta launch of Collusion in September and the official public release in October. So bookmark the site 🙂 and I will keep you posted!

Stuart 😀
(A very eager and excited Collusion Customer)