Your website that is. How fast should web pages load? There is a great discussion here that shows that, while there are no standards, there is potentially a maximum load time of 0.25 seconds. That’s the time it takes people to see something and then take action.
Right now the research shows that the expected time for a page load is around 2 seconds. The info graphic on this page does a great job at explaining why and how difficult that is to achieve.
So how do you achieve it?
There are three areas of technology provided by CDNs that, acting together, deliver high performing websites.
Firstly, caching (Level 3’s Site Delivery) replicates static parts of a web page closer to the consumer of the web site. Static objects are those viewed by all, or most, visitors to the web site; graphics, bits of Java script, the HTML code, etc. The CDN’s ability to replicate these parts of a web page reduces the latency associated with moving the bits and so speeds up the experience.
Secondly, network optimisation (Level 3’s Site Accelerator) speeds up the delivery of dynamic objects from the web site consumer to the location of the web site itself – known as the origin. Dynamic objects are those created for each individual viewer of the web site and so cannot be cached. An application, a shopping cart, a personalised news page, etc. will all be dynamic. Site Accelerator uses a variety of TCP/IP manipulations and compression algorithms in order to create a fast path through the Internet. Of course we also benefit from owning the network between our CDN edge and the web site origin. That network has QoS (Quality of service) built in. Our competitors have to build technologies to overcome the fact that QoS is lost when bits pass through the network boundaries between network operators.
Thirdly HTML optimisation (Level 3’s Site Transformer) changes the HTML code of the web site itself, in real time, to improve the speed of delivery. We do this by combining several small objects into a larger one in order to minimise the TCP/IP overhead associated with each one- using knowledge of the most likely flow through a web site to send data in advance (when a consumer is thinking or reading) so that it is already there when a person clicks on something, providing different optimisations depending on the consumers browser because every browser has different HTML optimisations built it – and many other clever tricks!
Of course the nature of every web site is different. Some have more static content, some have more dynamic content, and some have more optimised HTML code than others. Providing all three techniques is therefore important in order to get the best page load time.
But the techniques are also synergistic. 1+1+1 really does equal more than 3 in this case.
About Mark Taylor
