This is what the internet feels like with a CDN. Sort of.

The other day, a client gave us the green light to move their site. They’d been on a cheapo shared hosting plan that might be great for hosting a blog that no-one reads, but wasn’t a match for an up-and-coming e-commerce business. After wrestling with some stubborn plugins, we had the site up. And shortly after that, it went from “up” to “flying.” Page load speed skyrocketed, and generously-sized product images popped up instantly. It wasn’t voodoo magic (though it kind of felt like it.) The real power behind this significant speed boost was that we’d turned on our CDN. Which raises the important question:

What in the heck is a CDN, anyway?

A CDN is another of technology’s infinite 3-letter acronyms. In this case, it’s the abbreviated version of Content Delivery Network, and for those of us who live for immediate gratification, it’s the best thing since broadband. There are lots of different executions of a Content Delivery Network, but at their core, they’re a series of computers that are closer to you and have the internet stuff that you want. Like that new Netflix series you’re binging or that especially awesome cat video.

What a CDN actually does

The internet is like a baseball stadium. A zillion people in a zillion seats, all who want something different from the vendors. Now imagine you’re at one end, and the hot dog guy is at the other. He hands your hot dog to the first person, who passes it to the next and the next. Eventually, you get a somewhat rumpled and overpriced hot dog.

That’s sort of how Internet content works. Now imagine you’re at the end of the row, standing next to the hot dog guy. You raise your hand, and boom, you have a hot dog. Now look around our metaphorical stadium. See all those other hot dog vendors? That’s a Content Delivery Network. Multiple places serving up the same data.  It’s crowded category, but a few of the players in this sector include Akamai, Rackspace, CloudFlare, and this little company called Amazon.

How a Content Delivery Network works

There’s not a single model for Content Delivery Network, but there are three main elements to a CND: web cache, load balancing, and request routing. Web caching is having the data you want, queued up and ready to go. In our baseball analogy, it’s the vendor holding out a hot dog and asking if you want to buy it. It’s right in front of you, ready to go. Load balancing is more like checking out at Costco. There are a couple of lanes open, and everything is going fine. Suddenly ten people with overflowing carts all get in the same two lanes. Costco quickly opens more registers and sends a couple of people to each lane, and everyone checks out faster. Request routing is shortening the distance between you and the content you want. You ask for a French cat video, but instead of pulling from a server in France, you get it from a server in Chicago.

Why you need a CDN

Today’s Internet users not only want access to everything there is RIGHT NOW, they’re also merciless towards sites that don’t meet that expectation. As your page load time increases, so does your page abandonment rate.

Simply put:

fast page load = happy users
slow page load = no users.


Nobody likes a slow web page.

If you want a bit more detail about the grim consequences of slow page loads, see this sweet infographic over at Kissmetrics or this blog post.

Adding a CDN to your site

Many hosting providers offer CDN services as part of their hosting package, and they can walk you through enabling the service. If your hosting provider doesn’t offer CDN, there companies like Cloudflare who can add your site to their content delivery network. Full disclosure: we use — and love — Cloudflare. But there are plenty of other great options out there.