Howto: Speeding up apps using a CDN
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.
Only 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.
Costs
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.
2 Responses to “Howto: Speeding up apps using a CDN”
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Thanks for your explanation. You say a CDN suits perfectly for a website hosted in the Netherlands. I’ve always thought that a CDN is mostly used for sites in the cloud, which implicates that the websites is not hosted in the Netherlands or any particular country, but on different servers in the cloud worldwide. Is it possible to use a CDN with a traditional hosting solutions in a single datacenter?
Hi Darren, you can make excellent use of a CDN in a traditional hosting environment. You just need to ensure that the static content is as close to the end user as possible. Only dynamic content will be requested from the single datacenter. In most cases this will be a very small part of a website like only some text. Use it this way can be a great performance boost.
Large high traffic websites will place their servers in separate geographically locations so that even the dynamic part will be extremely fast. In most cases this is a quite expensive solution and therefor not interesting for normal websites.