Content delivery network: what is a CDN?

A content delivery network, or CDN, can make the difference between a slow site and a visited site. Find out how.

Fidel Chaves
5 min read

What’s a CDN?

Any sufficiently advanced technology is indistinguishable from magic. -- Arthur C. Clarke

 

CDN stands for content delivery network, and what is it? Well, a network to deliver content…

 

Wait, wait, wait! Don’t go. I’ll promise there is a better explanation afterward, but I needed that introduction.

 

You probably know that everything you see online has to actually be somewhere in the world (physically, I mean). That’s why I’ll assume you are familiar with the term “server”, those magical places where every piece of digital information is stored away and retrieved. If you know that, then you understand the problem that CDN’s solve: traveling the distance.

CDN examples explained

Let’s say that you have a website and you set up a server at your location. As with a delivery service, the people (users, clients, or readers) who try to access your website will get their information depending on their distance to the source, your server. Also, every person will be contacting that same source of information, so every request goes through the same channel. You see the problem, don’t you?

 

It’s all good when you have a website for a local business: imagine a bakery in your town. You know people who live far away may become your customers but won’t be as many to overflow your capacity. That is not true for digital businesses with a regional or global approach.

 

Think now of a newspaper or a social media site. They have users worldwide who want content as fast as possible, without any wait times, loading screens, or—God forbid—white screens. So if you were before dealing with a regular amount of local customers, now you are facing hordes of global users. Good thing I’m not the one that manages that.

 

That is the point where you need a CDN, a content delivery network, a network to deliver content. Please, lower your weapons. It’s going to make sense.

CDN’s infrastructure

CDN’s work as an infrastructure of relays called PoPs (points of presence). These PoPs work like franchises for your site thanks to using cached information that can be quickly accessed.

 

Let’s go back to the bakery example because I have a concrete mind. If you wanted to deliver your delicious goods worldwide, you wouldn’t make a single big shop. Instead, you would open up franchises in every town you have a relevant number of customers. Think of the poor guy pedaling his way across the Atlantic if not. Your best strategy is to replicate your content far away and stock them up from that central production point. The analogy starts to break down, so I’ll quickly return to PoPs.

 

Points of presence then work in a way that alleviates the central server, decentralizes the traffic, and allows you to provide what your user needs. This network of PoPs relies on the server to get information to store up in the cache. Thanks to this, content delivery can beat the speed of light, well not really, but it’s pretty cool. In the past, users waited on a scale of seconds. But thanks to content delivery networks, it transformed into milliseconds.

More benefits of a content delivery network

CDN benefits do not stop there. Thanks to its logic, CDN’s help out when suffering a distributed denial of service (DDoS) attack. These kinds of attacks are simple in nature: they consist of producing a traffic peak to a specific site to make it crash. It is like blocking a freeway with cars that go nowhere, and the only reason for being there is to cause a traffic jam. CDNs allow the site’s owners to avoid these attacks by simply widening the freeway. As you are not actually contacting the central server, the people committing the attack cannot overflow the connection.

 

Do you know what else looks like a DDoS attack? Breaking news. Yeah. In his talk, Arthur Bergman explains perfectly how a CDN works and how a news event can mimic a DDoS attack. Think of when someone famous dies, a terrible natural disaster strikes, or Kanye posts anything. The internet goes crazy, and you need infrastructure to deal with peak traffic.

 

Let’s then summarize the CDN advantages for your site:

  • Speed, performance, and quality: forget about waiting seconds to load. Less than 1 second is the way to go.
  • Security, offload, and availability: DDoS attacks? A celebrity died? No worries, nothing can take you down.
  • More access, less bounce rate: your server's long and narrow street can turn into a freeway system.

Content delivery network main providers

CDNs are essential to accelerate internet content delivery by providing excellent service to users all over the world. Be fast enough to keep everyone updated and optimize the resources you have available. Though these are good enough benefits, a CDN can help out a growing business as there is no need to attach a dedicated team of developers to it, like for servers; plus, buying more hardware is not a requirement.

 

To this day, there are plenty of CDN providers. It would take a dedicated article just to compare them, so I’ll leave the list below for those interested. If you feel like reading a detailed breakdown, let me know.

 

  • Cloudflare
  • Fastly
  • KeyCDN
  • AWS CloudFront
  • Akamai
  • CDN77
  • Microsoft Azure CDN

 

At Awkbit, we believe that the best service is an optimized service. Whether by integrating technologies, leveraging open source, or setting up best practices, our goal is to increase speed, reliability, and scalability. That is why content delivery networks come into play. Are you ready to become an international website? Do you want to integrate into the global digital space?

Reach Out!

Sources & further reading