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A Guide to Content Delivery Network: What Is a CDN, How It Works and How It Helps Your Website

Single server (left) Vs Content Delivery Network (right) (source).

Loading speed is one of the most critical factors that can make or break your website’s success. Fortunately, you can improve its speed in several ways such as by decreasing the number of graphics, optimizing images, and using simple web design.

Content delivery network (CDN) is also becoming an increasingly popular technique to improve the loading speed of your website. Several leading sites have already started using a CDN. According to BuiltWith, more than 66% of the top 10,000 websites are using a content delivery network.

Content Delivery Network Usage Statistics (source).

Let’s find out more about CDN.

What Is CDN Caching?

 A content delivery network is a network of servers that deliver web pages and other content to users based on their geographical locations. In other words, it helps reduce the time taken by the remote server to respond back with the data requested by the end-users.

Usually, it catches static content stored on the nearest possible server to the user’s geographical location. As the distance traveled by the data decreases, the delivery time (or the loading speed) improves.

For example, let’s say you are accessing a website from Mumbai, India. The primary server hosting this site is in London, UK. Owing to the vast physical distance, it will take considerable time for the website to load.

However, if the site is using a CDN, it will connect you to the nearest edge servers (CDN servers), which in turn, will retrieve the content from the original server.

1. Better Loading Speed

The most apparent benefit of a CDN is the enhanced page loading speed. The edge servers will retrieve the content from the original server for the first time only. After your first request, the servers nearest to your location will cache the content and save it.

If you request the same content again, one of those edge servers will deliver it to you directly, reducing the loading time further. A CDN can store different types of content including images, CSS, JavaScript, HTML along with 4K and HD videos. It can reduce the amount of data using techniques such as minification and file compression.

2. Lower Bandwidth Costs

Some of the web hosting service providers charge based on the bandwidth. If you are using this type of service, using a CDN can reduce your hosting costs.

As CDN uses multiple server locations to deliver the content, not every request will hit the source server. Thus, your bandwidth costs will be lower.

3. Improved SEO

The faster loading speed will also improve your search engine rankings. We will cover this topic in detail later.

Potential Security Risks and Overcoming Them

Although CDN offers several advantages, it does pose a few security risks and malfunctions that may compromise the integrity of your website. However, you can mitigate these potential issues with proper configuration and implementation.

1. Cross-Site Security Issues

You are going to face these issues if your website uses SSL, but not CDN. It usually happens because a CDN can deliver encrypted content on a non-encrypted site, but not the other way round. If your CDN is forwarding scripts, your website will load partially owing to a cross-site scripting warning. To overcome this problem, you have to run SSL on your CDN as well as the site.

2. Duplicate Content Issues

Duplicate content issues may arise occasionally. Usually, a misconfigured CDN causes duplicate content issues. Chances are your CDN service provider will allow you to change the necessary configurations. You can also set up canonicalization for the content to prevent duplication.

3. Delayed Website Loading

Sometimes CDN may result in delayed loading time if you have render-blocking media attached to it. Asynchronous media loading is essential for a fast loading site.

In other words, the text on your site can’t wait until the images load correctly. Poor implementation of the CDN often causes this problem. So, ensuring that your server is fully optimized can mitigate this issue.

What Can Businesses Do If They Run More Than One CDN?

 Most businesses will choose only one CDN provider. However, the trend is gradually shifting towards using more than one CDN providers. Multiple CDNs come with plenty of benefits such as comprehensive coverage, improved loading speed, reduced downtime due to single provider outage and cheaper hosting costs.

If you intend to use more than one CDN, there are two ways to do it.

1. Automated Multi-CDN Architecture

In this case, you can hire a larger multi-CDN provider who will manage your web traffic across multiple CDNs automatically. It is essentially outsourcing your multi-CDN management. As a result, you will end up saving considerable time, labor, and money.

You also don’t need to worry about updates and optimization as the service provider will take care of it. They will automatically divert the web traffic evenly across all the CDNs. However, as the web traffic is not managed by CDNs directly, routing decisions often remain restricted.

2. DNS Load Balancing

The DNS refers to Domain Name System comprising the hostnames of the CDN providers. The DNS recognizes the hostnames of a CDN provider, which in turn, identifies the IP address of the web servers nearest to your users. Thus, you have the freedom to diversify your services. You can also avoid vendor lock-in.

The most significant advantage of this system is the exceptionally high loading speed. Most DNS providers are now using integrated monitoring nodes to identify the fastest CDN. Web traffic is usually routed to the fastest server. Thus, your website always loads quicker.

However, this option is also costlier compared to automated CDN management as you will have to pay each CDN provider separately. Similarly, you will need to configure and optimize each CDN separately as well, turning this method into a labor-intensive and time-consuming option.

How Can CDN Help Improve Your Site’s SEO?

 As you know, the loading speed is one of the most critical factors for improving your site’s SEO. However, CDN can boost the SEO in other ways as well.

1. Improved Performance

Increased page loading speed leads to better content delivery, which in turn, enhances the user experience. It is perhaps the most crucial SEO factor that Google uses to determine the search engine ranking of your site. With mobile traffic increasing, CDN is going to be even more necessary to improve the site performance and hence, the user experience.

2. HTTPS and HTTP/2 Security

HTTPS is also a critical SEO factor. Secure Sockets Layer (SSL) or Transport Layer Security (TLS) protection plays a critical role in enhancing and maintaining your SERP ranking. The CDN allows you to run your website on secure servers even though the main site isn’t secure.

Plus, most CDNs have extended support to HTTP/2 protocol as well, which Google considers as one of the best SEO practices. This can also boost your ranking, especially if your web hosting provider hasn’t started supporting this security protocol yet.

3. Relevant Content Delivery

The CDN also ensures the delivery of the most relevant and error-free content. Most CDN providers will regularly purge your website content using specific caching algorithms and canonical headers. This process eliminates duplicate content creation problems. As users receive the most relevant content, they are more like keep coming back.

4. DDoS Attack Protection

As the CDN feeds the data to the end user from multiple locations across the globe, it can reduce the chances of a Distributed Denial of Service (DDoS) attack on your site.

Most CDNs can analyze and assimilate unusual traffic spikes. So, when they detect potentially threatening web traffic, they will divert it to specific scrubbing nodes that act as black holes. As the dangerous traffic gets absorbed into these nodes, your website remains protected from the attack. This increased web security will also boost your SEO.

Wrapping Up

 A content delivery network is probably the best means to speed up your website. However, using a CDN also comes with a few risks that you can mitigate with proper configuration. That’s why you need to know about what a CDN is, how it works, and how it can improve your site’s SEO.

Hopefully, the pointers given in this article will clear all your doubts about CDN. If you are still not sure of using this technology, ask your queries in the comment section below.



About the author: Manish Dudharejia 

I am the President and Founder of E2M Solutions Inc, a San Diego Based Digital Agency that specializes in White Label Services for Website Design & Development and eCommerce SEO. With over 10 years of experience in the Technology and Digital Marketing industry, I am passionate about helping online businesses to take their branding to the next level.

Connect with Manish on Twitter.

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