Howto: Speeding up apps using a CDN

Blog post   •   Feb 05, 2010 06:16 EST

A Content Delivery Network or Content Distribution Network (CDN) could increase application performance. Many high traffic websites are using a CDN to decrease latency (the amount of time it takes to send a data packet from source to destination). High latency will slow down transfers and that’s why CDN emerged.

A CDN is a network of strategically placed servers that delivers static content to an end user. In most cases the static content will be images, videos, files, et cetera. Based on the geographic location of the end user, the content will be send from the nearest static content server. The goal of a CDN is to deliver the requested content as fast as possible.

nly one initial DNS request will have to be send to the primary location. The DNS will respond with the location based local IP, so all static content will be requested from the nearest strategically placed server.

CDN benefits

Using a CDN has several benefits. The servers are placed close to the end user, which will decrease latency and a better experience for the end user. For instance, streaming media quality improves without having lag. The primary server location doesn’t have to handle all requests because the static content will be served from a CDN. This leads to less bandwidth usage. CDN’s are redundant, therefore they can offer 100% availability even with hardware or network outages.

Using a CDN doesn’t always give a performance boost. You have to know the geographic location of the end user to determine whether it is useful to set up a CDN.

When to use a CDN

A website is hosted in the Netherlands. You have visitors from all over the world. When an end user in Singapore requests this website the loading time of this website will be relatively high because of the geographic distance between the 2 locations. It would be much better to have a mirrored location near Singapore. In this case it can be a big advantage.

When not to use a CDN

When you only have end users located in the Netherlands, a server in the Netherlands will be sufficient. But if performance problems arise, it’s worth considering. By separating the content you are able to separate the load.


In the past, every high traffic site has made an investment for their own CDN. An investment like this is not necessary anymore. Compared to a few years ago there are a lot of commercial CDN suppliers. Due to competition, the costs are relative low. You only pay for what you use.

Commercial CDNs

Nowadays there are a lot of CDN suppliers. Some of them mentioned below:

Want to know more?

In my next blog I will show how to change an existing application in only 5 simple steps for using a CDN.

Niek Waarbroek, Jitscale cloud management