In this post I’ll try to bring more clarity to the murky world of Content Delivery Networks (CDNs), how they work, and why they are so important for enterprise websites or anyone looking to scale their online business.
What are the challenges facing an evolving online business?
Before getting into the specifics of CDNs, lets take a step back and understand what are some key challenges an online business faces. Imagine I have an online blog that caters to the travel industry. I’ve hit a sweet spot with my content and am selling travel products, aggregating reviews of destinations around the world, and my site traffic is taking off. I even recently started a mobile app for my site and really might be onto something big here! As I look to grow my site’s online presence, here are some key challenges I need to think about:
1 . Performance
According to Google, 53% of mobile users today abandon sites that take longer than 3 seconds to load. A single second delay in website loading times results in a loss conversion of 7%. These are brutal stats and getting even more harsh everyday. Essentially the success of my entire business hinges on my site performance. My travel site is getting more geographically dispersed visitors everyday, but that traffic also translates to slow page load times – which is hurting me everyday.
Another challenge that comes with a growing online business is site availability. Increased traffic means an increased load on my website server, which can overwhelm and cause it to crash. Noelle, a travel & adventure enthusiast just heard about my site from her friend. She tries to check it out but my site is down. She won’t be coming back to my site.
We live in a harsh world today. Popularity can often translate to attracting malicious actors. The success of my travel website means that it make it a prime candidate for online bots, hackers, data theft, and DDoS attacks. In the excitement of keeping up with a growing business, this is the last thing online business owners think of.
Think of CDNs as an intermediary you have between your website and your hosting server to tackle the three challenges we mentioned above. CDNs place hundreds or thousands of their own servers in strategic geographically distributed locations around the world, and then retain copies of your website to distribute content to your users from locations closest to them, versus your hosting server.
This distributed reach provided by CDNs is the key to solving the three big challenges mentioned above. To understand this further, let’s use an analogy- Diet Coke! Coca Cola is based in Atlanta, which is where its primary bottling plant is based, manufacturing ridiculously high gallons of Diet Coke every day. Now imagine if this was also the only location where these Diet Coke bottles were sold. Consumers would run into three very similarly themed problems:
- Performance: As someone living in Boston, I’d have to drive all the way to the Coke facility in Atlanta to buy a Diet Coke. That’s a lot of time. Once I get there, I’d be competing with millions of other Diet Coke enthusiasts and probably spending hours waiting in line to get my hands on a Diet Coke. That’s even more painful, and a lot more time.
- Reliability: Surely something’s got to give when you have Diet Coke enthusiasts from all over the world waiting to get their hands on their favorite beverage all at one location. The Atlanta facility will be swamped and not be able to handle the scale of growing traffic. Essentially lots of chaos and bottlenecks, and the facility will need to be shut down frequently at random times just so everyone in there can catch a breath
- Security: Anywhere there is demand, there are malicious actors. All of this chaos will attract all kinds of threats – bootleggers, pickpockets making use of the large crowds to steal things, evil forces looking to add to the chaos by creating false demand to take down the manufacturing facility, etc
Thankfully, the Atlanta manufacturing facility isn’t the only place in the world Diet Cokes are sold. Coca Cola leverages a massively distributed world wide network of bottling facilities, retailers, and mom & pop stores to make sure anybody wanting a Diet Coke simply has to go to a local station within minutes of their location. Thus avoiding any bottlenecks due to travel, large crowds, chaos, or malicious actors.
In a nutshell, that is what Content Delivery Networks do as well. CDN providers make use of a large globally distributed footprint of local servers to store (cache) frequently accessed information from their clients. For example, Akamai, the largest CDN is the world has about 220,000 local servers in more than 1,500 cities around the world which it uses to cache frequently accessed content.