Express Content Delivery with CDN

A Content Delivery Network, or CDN, is exactly what the name suggests—it helps deliver content faster and ensures users can access it without delay. This is done by distributing servers across different locations. CDNs handle all sorts of content, including HTML pages, JavaScript files, stylesheets, images, videos, and more. Most major companies like Facebook, Netflix, and Amazon rely on CDNs to manage their web traffic. Let’s dive into what a CDN is, how it works, and the benefits of using one.

So, what exactly is a CDN?

Like I mentioned, a CDN distributes servers around the world. When a user connects to your site, the server closest to them delivers the content they need, instead of relying on the origin server. This reduces the time it takes for content to load.

CDN Service Providers

There are lots of CDN providers out there. Some offer free plans, which are great for small businesses, while others might have data centers only in specific countries or may lack features like DDoS protection. You’ll need to choose a CDN provider based on what your service needs. Here’s a quick overview of three well-known CDN providers: Cloudflare, Google Cloud CDN, and Amazon CloudFront.

• CloudFlare
  • Offers a free plan, making it ideal for individuals or small businesses.
  • Supports SSL certificates.
  • Has over 180 data centers worldwide.
• Google Cloud CDN
  • Part of Google’s global network.
  • Like CloudFlare, it supports SSL certificates.
  • As of 2021, there are 90 data centers.
• Amazon CloudFront
  • AWS’s CDN service.
  • Known for its speed, but can have a steep learning curve for non-developers.

How Does a CDN Work?

CDNs set up servers all over the world, apart from the origin server. These servers are positioned at Internet Exchange Points (IXPs), which allow different networks to interact.

Here’s an image from Cloudflare’s What is CDN? page that explains how CDNs work.

In the image, the origin server is located in the States, and the blue CDN servers are spread out around the world. (There are actually over 180 data centers globally, so there are way more than shown in this image!) When a user in Australia makes a request, instead of the content being delivered all the way from the States, the closest CDN server to Australia will handle it, speeding up the process.

What Are the Benefits of Using a CDN?

You might wonder, is faster loading the only reason so many global companies use CDNs? The quick answer will be no. Aside from speed, there are a few other advantages that come with using a CDN.

Faster Loading Speeds

If your site takes too long to load, users will likely leave. CDNs help reduce load times by using data centers all over the world, meaning users don’t have to wait for data to travel long distances. Instead, they connect to the closest data center, which gets them the content faster.

Reliability and Redundancy

Things like cyberattacks or sudden traffic spikes can overload a web server, making your site or service inaccessible. CDNs help minimize downtime by using load balancing, which spreads the traffic across multiple servers. If one server gets overwhelmed, the traffic can be rerouted to other active servers, keeping the service running smoothly. CDNs can even block access to the site if something goes wrong at the data center level.

Data Protection

Let’s talk about security. CDNs that offer SSL certificates provide data protection, which is crucial.

An SSL certificate allows a website to switch from HTTP to HTTPS. It encrypts internet traffic and verifies the identity of the server.

How Can You Use a CDN?

If you’ve done web development before, you’ve probably already used a CDN without realizing it. Think about services like Google Web Fonts or the Bootstrap CDN. To use them, all you need to do is import them via their CDN address.

When the CDN handles a request for the first time, it fetches the content from the origin server and sends it to the user. At the same time, the CDN caches the content. For subsequent requests, the CDN will serve the cached content instead of going back to the origin server. The CDN provider manages the expiration time for cached content.

For instance, if you’re loading images, you can replace the file path with a CDN URL like this:

// as-is
<image src="/resource/image.png" alt="image-description" />

// to-be
<image src={CDN_IMAGE_URL} alt="image-description" />

If you want to use a CDN for your own service, you’ll need to point your domain or IP address to the CDN provider’s servers by configuring your DNS settings. You’ll have to adjust the CName records for each domain. I haven’t tried this myself yet, but when I do, I’ll definitely write a post about it!

Final Thoughts

Although I’ve used CDNs to pull external resources for a while, I hadn’t really thought about how they work or why they’re so beneficial. Writing this post helped me understand what CDNs are and how they improve website performance. It also made me want to dive deeper into topics like caching and SSL certificates, so maybe I’ll write about those next time. Stay tuned!