Why Use a CDN: Advantages and Downsides of Using a CDN


By Ann Oliver

With more than 4.5 billion users, the internet has become the biggest virtual landscape today. When businesses and enterprises can utilise it for extending their business reach and increase sales, the challenge here is to ensure a seamless user experience with prompt page loading, faster content delivery, and decreased latency. 

Implementing a CDN can be the ultimate solution to optimise your site performance and reach more people and turn them into converting leads.

Are you a beginner in the realm of the web and wondering about why use a CDN? To help you get an in-depth insight into this widely adopted service, here is a comprehensive overview. 

Content Delivery Network

Content Delivery Networks or CDNs are a complex cluster of networks consisting of web servers. When you integrate a CDN with your website, its edge servers (PoPs) distribute your site content throughout the network after caching. 

Thus your user gets served from the server located nearby, which, in return, ensures faster web page loading and scalability.

Let’s understand the functionality of a CDN with an example:

  • Let’s assume you run a website based in London. When a user requests access to an image of your site from San Francisco, the request has to travel a long way as these two cities are around 5,351 miles apart.
  • Now, if you depend on your London-based hosting server to respond to that request and deliver the image to the target user, that might cause a delay of almost 300 milliseconds
  • When a delay of 3-second in page loading can make around 40% of visitors abandon a webpage, the subsequent requests a website receives will only add to this round-trip delay and make your site slow down. 
  • But when you incorporate a CDN service, it, with its caching servers located worldwide, can deliver that requested image to the user located in San Francisco from that user’s nearest server. 
  • So, the user can get access to the requested web content in no time!

Why Use a CDN

Now that you have got a brief overview of CDN functionality, let’s put insight into why use a CDN:

Optimised Performance with a Speedy Site

The leading cause of integrating a CDN with a website is its power to accelerate your site performance. Thus it decreases latency which can speed up the site like never before! 

With the rapid incorporation of videos in websites, the webpage size has risen by around 243% from 2010 to 2016. 

When you use a CDN with your site, it will optimise these media files, combat buffering, and improve loading time, optimising the website performance. 

PageSpeed Insights results for https://www.cloudflare.com/en-gb/

Limits Bandwidth Usage 

When you cannot deny the significance of a traditional web hosting service, using a CDN is a must to mitigate the downsides of a hosting provider. 

A CDN has its caching servers worldwide to offload traffic from the hosting server. So the origin server has to respond to fewer requests and transfer fewer data. The fewer data the origin server has to handle, the less bandwidth is used, limiting the bandwidth expenses. 

Website Availability and Better Traffic Management

A CDN, with its geographically located data centers, can manage and distribute traffic better. CDNs can cache your static content and distribute them among its servers. So even if the origin server is down, the site will still be available for some visitors as the content can be delivered by CDN servers. 

Don’t worry if your website is full of dynamic content. You will find a handful of CDN providers serving both static and dynamic content.

Better Security and DDoS Attack Mitigation

Each server of almost all CDN providers comes with Web Application Firewall (WAF) protection to keep your website protected from suspicious IPs and requests. WAF is a superior security layer of a CDN that enables caching servers to measure the malicious incoming access requests and block them before reaching the main server. 

Edge servers also feature DDoS attack protection, TLS encryption, Secure Token, SSL certificate, etc., to offer you a highly encrypted and secured system. 

SEO Advantages

With the exponential increase in websites and their users, the significance of SEO is beyond words. When you want your site to be SEO optimised, you need to ensure optimal page loading. 

Google, the leading search engine, prefers speedy websites and ranks them higher. The faster the pages load, the better it is for SEO, and your chances increase to rank higher on the SERPs. 

Another vital yet overlooked factor for ranking higher on Google is how optimised your site images are. Image CDNs optimise images by resizing or compressing them. When your site images are optimised, it improves site speed, which boosts the SEO, improving the crawling frequency.

Increased Redundancy

A CDN is a highly distributed system that comes with increased redundancy. It delivers the searched content from the PoP nearby the visitor. So even if an edge server goes down, CDN can deliver the content from another nearby PoP, which means you can offer your visitors a better and reliable service. 

CDN Cost

A CDN provider offers third-party services that may come in different pricing based on various factors:

  • SSL certificate
  • Bandwidth 
  • Geographic locations to cover

While you have high-end, expensive CDNs for commercial use, there are quality-performance, cost-effective CDNs available for mid/small-sized sites.

When CDN Makes No Sense

Though CDNs can offer surpassing benefits to your business, there are some points when implementing a CDN can be less necessary:

  • If your website experiences low traffic with few searches, adding a CDN service with the site may be less required. 
  • When your website users are from the same geographic region, you don’t require a CDN server. While serving the local people, using a CDN for caching and storing content throughout its edge servers scattered in multiple locations worldwide is unnecessary. 

Cons of a CDN

Though few, using a CDN service may come with some downsides:

  • Using a CDN can add to your expenses a little bit. Though not much, you may have to spend £0.072/GB
  • Though rare, storing the files on all edge servers is prone to security vulnerability.
  • CDNs offer smooth integration with the most popular CMS like WordPress or Drupal. But you may require to modify codes while developing custom applications.