Content Delivery Networks (CDNs): How They Work and Why Your Website Needs One

When searching for ways to improve your website’s performance, you’ll probably stumble upon content delivery networks (CDNs). Also known as a content distribution network, they’ve become exceedingly popular. Research by the internet services company BuiltWith shows that nearly half of the world’s top 1 million websites use a CDN. So, what is a CDN, and how can it benefit your website?

How CDNs Work

A CDN is a supplemental web hosting service that uses a network of proxy servers to serve copies of your website’s static content to its visitors. It essentially caches your website’s static content, including Hypertext Markup Language (HTML) pages and images, which it serves to visitors upon request.

The proxy servers used in CDNs are geographically dispersed. They aren’t all located in a single region. Rather, a CDN’s proxy servers are spread across many regions. When a user attempts to visit your website, the CDN will automatically select the proxy server that’s closest to his or her location. The CDN will then send the requested static content to the user from this proxy server.

It’s important to note that CDNs only serve static content. Dynamic content is generated in real time when requested by a visitor. Therefore, CDNs can’t cache it. They can only cache prebuilt or static content. If your website contains any dynamic content, your site’s origin server will send it to visitors.

Reduced Visitor Load Times

Visitors will be able to load your website more quickly if it uses a CDN. Whether it’s shared, virtual private server (VPS) or dedicated, conventional web hosting services serve content from a single server. Visitors who are near your website’s origin server may encounter fast load times, but those who are far away from it will likely encounter slower load times. After all, data must travel from your website’s origin server to the visitor’s computer or device, so a longer distance translates into longer load times.

A CDN can reduce visitor load times by serving static content from the closest proxy server. You’ll still need to use a conventional web hosting service. A CDN simply pulls static content from your website’s origin server and saves these copies on various proxy servers. The origin server, however, won’t be used to serve static content. With a CDN configured, your website’s static content will be served from the proxy server closest to the visitor, allowing for shorter load times.

DDoS Protection

A CDN offers a strong layer of protection against distributed denial-of-service (DDoS) attacks by rerouting traffic away from your website’s origin server. Some online businesses, in fact, use a CDN specifically for DDoS protection.

Not to be confused with a denial-of-service (DoS) attack, a DDoS attack can take down your website by flooding its origin server with an exorbitant number of requests from many different internet protocol (IP) addresses. As your website’s origin server buckles under the weight of this spam traffic, it may fail to load.

A CDN can mitigate the effects of a DDoS attack by absorbing some of the spam traffic. If your website uses a CDN, its origin server won’t be the exclusive target of a DDoS attack. Instead, the spam traffic will be distributed across hundreds, potentially even thousands, of proxy servers. With less spam traffic reaching its origin server, your website should be able to withstand a DDoS attack.

Load Balancing

Another reason to use a CDN is load balancing. As your website becomes more popular, its traffic will increase. All of these visitors can strain your website’s origin server by consuming its resources. Each time a visitor loads a page on your website, the origin server will consume bandwidth, Central Processing Unit (CPU) time and other resources. Load balancing is an innate feature in CDNs that protects your website’s origin server from traffic spikes such as this.

Load balancing is how CDNs mitigate the effects of a DDoS attack. It distributes traffic across multiple servers so that no single server, including your website’s origin server, is the sole recipient of the traffic. From legitimate traffic to spam traffic, a CDN’s load balancing feature will spread it across multiple servers.

Lower Web Hosting Costs

A CDN can save you money on the cost of web hosting. Conventional web hosting services are usually sold in tiered packages based on the amount of resources they provide. If your website generates a lot of traffic, it may require a high-tiered web hosting package. Otherwise, the lack of resources could cause longer visitor load times, or it may take your website completely offline.

The good news is that a CDN can lower your web hosting costs. Rather than an expensive high-tiered plan, you can choose a cheaper, lower-tiered web hosting package without any adverse effect on your website’s speed or performance. Many CDNs are capable of handling 40 percent to 60 percent of a typical website’s traffic. In other words, they can slash your website’s resource needs in half.

Improved SEO

Using a CDN even offers search engine optimization (SEO) benefits. It will make your website load faster by reducing the distance data must travel to reach visitors. How does this benefit SEO? Search engines use visitor load times as a signal when calculating rankings. If your website is fast and loads quickly for visitors, they’ll rank it higher.

In addition to visitor load times, search engines analyze uptime for ranking purposes. If your website is constantly down, it probably won’t earn high rankings. Search engines don’t want to show their users listings for offline websites because it fosters a negative searching experience. A CDN can increase your website’s uptime via load balancing, making it a more attractive candidate for first-page rankings.

No matter what kind of website you operate, a CDN is worth the nominal investment. It will serve copies of your website’s static content from a large collection of proxy servers distributed across the world. With a CDN configured, your website will have reduced visitor load times, protection from DDoS attacks, load balancing, lower web hosting costs and improved SEO.

Interested in quality hosting with CDN? View our hosting plan offerings.

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