10 myths about content delivery networks


1. CDNs will only accelerate websites

The most basic function of a content delivery network is to cache and deliver your static content from its servers around the world. Since the servers are distributed geographically, your audience will always be connected to a server close to them which in turn will allow them to download the static content in a faster and more reliable manner. The static content could be your website's logo, any other image on the website, it's CSS and Javascript files. This, in turn, will lower the time needed for your website to fully load in the browser of the visitor. Some CDNs are capable of dynamic content acceleration, which will make your website or online store even faster. However, there is a lot more content that needs to be delivered around the globe daily - video on demand, live broadcasts, audio podcasts, file downloads and even the software updates on your smartphone. When you watch something on Netflix, the video is delivered from a CDN. When you listen to a podcast on iTunes, the audio comes from a CDN. The basic function of static content caching is at the core of all of these and as such, content delivery networks are used for pretty much anything, including web acceleration. However, most people we talk to seem to believe that the only purpose of a CDN is to make a website faster. Well, obviously not.

2. CDNs are a silver bullet for SEO

SEO is a hot topic for a reason. How you rank in search engines can make or break your business, and as such it's crucial to ensure that apart from an effective content strategy, you also have a reliable and fast website. However, "fast" has more than one meaning. There is always the subjective "fast", or the perception of a fast loading website as seen by your visitors which is extremely important. But there is also the not so subjective "fast" as seen by a machine that evaluates the speed by taking into account the best practices for web development and optimisation. A content delivery network will definitely help you with the subjective part and some providers would even try to help with the not so subjective part, but in the end when you look at your page speed score in Google Insights, you either have a well structured and correctly built website or your score will be average and your SEO will still suffer even if your CDN provider is flawless.

3. CDNs are a silver bullet for server load

By offloading the delivery of heavy objects like large images, videos and file downloads to a CDN you are taking away from the job that your web host, VPS or dedicated server has to do, which naturally makes it faster and more consistent in its performance. However, if your website's code is not efficient, and your database is being flooded with requests when even a single page is being visited by a single visitor, your server would still appear to be overloaded and your website would still take a long time to load. A CDN is not a replacement for well-coded website.

4. A CDN is not needed if my audience is local

Probably one of the biggest misconceptions about content delivery networks is that you need one only if your visitors come from different countries and continents. A CDN provides you with reliability, as it's network is capable of detecting a failure in any one server at any given moment. When this happens your visitors are automatically redirected to the next closest healthy server, often without even noticing. At PUSHR we run on the third iteration of our failover system which is now able to redirect a live video stream without playback interruptions. On top of that, since CDNs are a managed type of service, you don't have to deal with server management, bandwidth problems and disk load issues yourself, and you are ready to absorb the peaks when your website, service or app gets featured online and gets flooded by visitors.

5. CDN services are expensive

A lot of people think that in order to use a CDN they would need to have a huge budget. That is not necessarily true. In the "Which CDN is best?" blog post we've already covered some of the things to consider when choosing a CDN provider, but in short, you don't want to have too many features that you don't need, too many points of presence that you won't use, and long-term contracts that would lock you in while the market is moving forward and prices of competitive services are going down.

6. The more points of presence, the better

Probably you don't need that many points that are 2-3ms away from each other. Unless you are a fortune 500 company, you most probably don't need to have points of presence in Zimbabwe and on the North Pole either. However, if your provider offers these exotic locations you can rest assured it costs them dearly to keep them in operation. A fraction of your bill will go towards these PoPs that you would never use, even if you are being given the option to turn them off for your account. If a provider's business model is incapable of offsetting these costs, then the performance of the less expensive points of presence that you use could be compromised to make up for the loses generated by the exotic ones. One frequent compromise is the amount of available bandwidth in each location. Most CDN services will not guarantee the throughput of their network and performance may suffer, especially during peak hours.

7. CDN services are for large websites only

CDNs bring speed, reliability and instant scalability, and the short answer to this is that the size of your audience doesn't mean much. What matters is your growth plan and the importance of your project, and if these dictate a strong online presence, good performance and high reliability then you do need a CDN.

8. A CDN is hard to implement and requires knowledge

This is another huge myth. Due to their complicated infrastructure, content delivery networks are often considered a service that would require developers to be involved and a rewrite of large portions of existing website or app code to take place prior to the integration. It's usually exactly the opposite since what is often needed is only the links to the static content to be changed in the website so that they point to the content delivery network instead of the website server itself. Pretty much every CDN service provider also offers a custom-built web control panel (at PUSHR we call it a dashboard) which allows the customer to control every aspect of the service via the click of a mouse button. The average time that our customers need to integrate our service is below 5 minutes and we are always there to help.

9. CDNs are a replacement for web hosting

Content delivery networks work on top of your web hosting service, but they can't be used to host your dynamic websites and databases. You'd still need something to run your website on, but the benefit is that depending on what amount of workload you manage to offload to the CDN, you should be able to move your website to a smaller and more affordable hosting plan. This is especially true for video streaming and software oriented websites and apps.

10. CDNs are a cure for hacks and attacks

A content delivery network could protect you from hacks and denial of service (DoS/DDoS) attacks. From WAFs (Web Application Firewalls) which aim to stop malicious activities against your web app, SAAS or CMS, to origin shields that hide and protect your server's IP address. However, there is no substitute for the work that you need to do on your end. If you are using a popular CMS like Wordpress, for example, you still need to protect your /wp-admin login page and take precautions to avoid xmlrpc and admin-ajax attacks. Changing your website's IP address once you've moved it behind the shield of the CDN service is also important, otherwise, an attacker could target it directly and bypass the origin shield. Hand-picking the plugins that you use is just as important, since vulnerabilities in them may open the door for malicious code inclusion, database injection attacks or simply DoS via flooding the website with requests that all take too long to be completed and ultimately lead to resources exhaustion.