If you’ve ever visited a website and wondered whether your internet was down or the site was just slow, you may have experienced a slow or unreliable content delivery network (CDN).
When working as they should, CDNs help websites handle heavy web traffic, improving load times and user experience.
Read on to learn how CDNs can impact your online business, your marketing, and your customers.
What is a CDN?
A content delivery network (CDN) is a system of geographically distributed servers that work together to deliver web content—such as images, videos, and application data—more quickly and reliably to users. By caching content at multiple locations, or points of presence (PoPs), CDNs reduce latency, improve load times, and enhance the overall user experience, making them essential for websites with high traffic or global audiences.
“CDNs spread the load of intense traffic demands across many servers,” explains independent UX/UI designer Dave Smyth. They can also, he adds, act as failovers, or automatic backup systems, keeping sites online even in the face of technical problems. “And because there are lots of servers, CDNs can offer good protection against distributed denial of service attacks (DDoS).”
How does a CDN work?
At a high level, CDN networks optimize web content delivery by minimizing the distance between internet users and the servers housing the web content they want to view.
If websites were libraries, CDNs would be small local branches, helping patrons access information quickly without trudging to faraway main branches.
Here is how CDNs work:
- Origin server: Every website has one or more origin servers. These servers operate like digital warehouses, storing a website’s web pages (images, text, code), software downloads, rich media (audio and video), and dynamic apps.
- Client request: When you type a domain name into your computer, your browser sends a message requesting the information you seek (in this case, a website). This action is called a client request.
- Content delivery network (CDN): If the website uses a CDN, instead of sending your client request to the origin server, it sends it to a nearby CDN server, reducing the time it takes for you to get the information you want.
If the content delivery network doesn’t have the requested file, it gets it from the origin servers and delivers it to you. Then, it caches the file to fulfill subsequent client requests faster.
CDN management software uses intelligent algorithms and machine learning to anticipate content requests, cache content on the CDN before it is requested, and synchronize with changing content on the origin server.
Types of CDNs
Traditional CDNs
A traditional CDN is a geographically distributed network of servers spread across the world. These servers cooperate to deliver website content to users quickly and reliably, no matter where they are.
Dynamic CDNs
Dynamic content adjusts to its users, displaying different information depending on their search history, location, interests, or other conditions. A dynamic CDN delivers dynamic content. For instance, when an ecommerce site’s product carousel widget displays a customer’s previous purchases, a dynamic CDN ensures the content adjusts appropriately so every customer sees their unique shopping history.
Peer-to-peer (P2P) CDNs
Peer-to-peer (P2P) CDNs rely on user devices to share content. Since they don’t require expensive centralized infrastructure, they tend to be cheaper than other CDNs. When a user requests content from a site that uses a P2P CDN, the server fetches it from user devices that have already accessed it.
Multi-CDN solutions
A multi-CDN solution is what it sounds like: a distribution solution that uses multiple CDN providers. This way, if one CDN goes down, the others can process client requests without interruption.
Regional CDNs
A regional CDN uses servers within a specific region or country. For example, if an ecommerce business only serves customers in the US and Canada, they might opt for a regional CDN with a network of servers in North America.
Cloud CDNs
Cloud CDNs use cloud service providers to deliver content to web users. Popular examples of these virtual servers include Amazon Web Services (AWS), Google Cloud, and Microsoft Azure.
Video CDNs
A video CDN is specifically designed to deliver content such as on-demand video and livestreams. Video CDNs are uniquely optimized for large video file sizes and bandwidth use.
Edge CDNs
Traditional CDNs draw cached content from geographically distributed servers to satisfy search requests quickly. Edge CDNs go beyond caching and delivering content; they also store and processit on servers near web users to produce even faster results.
Who benefits from using CDNs?
Any organization or individual who wants to improve their website users’ online experience—especially those who run complex or video-heavy websites with international audiences—should include a CDN in their web architecture.
That’s because CDNs:
- Improve the U/X for global users
- Cater to spikes in website traffic
- Reduce bandwidth consumption and costs
- Bolster website security
As commercial CDN adoption increases, fees decrease; sometimes, web hosting packages bundle in CDN costs.
Industries that rely on CDNs
Industries or businesses that rely on CDNs include:
- Ecommerce sites: Online stores use CDNs to speed load times—which can dramatically improve a site’s conversion rate—satisfy users’ expectations, and improve SEO.
- Video streaming services: Streaming services like YouTube and Netflix use CDNs to ensure viewers receive large video files smoothly, with minimal buffering.
- Gaming sites: Gaming platforms like Twitch use large-scale CDNs so gamers can enjoy real-time loading without lags.
- News organizations: News websites offer a lot of content. Dynamic CDNs let them quickly deliver videos, images, and text to a global audience.
- Social media platforms: Social media platforms use CDNs to load users’ news feeds quickly, storing and retrieving the billions of posts viewed daily (including 200 billion views on Facebook and Instagram alone).
Advantages of CDNs
Here are some of the reasons organizations choose CDNs to help distribute their websites:
Improved user experience and website performance
CDNs eliminate long wait times for downloads and streaming, improving customer satisfaction and user experience, especially for websites with high bandwidth consumption.
Optimized bandwidth costs and consumption
Distributing content through CDNs reduces web server load times and reduces or eliminates local network bottlenecks, reducing bandwidth requirements and enabling better network usage.
More simultaneous users
More users can be supported simultaneously with edge servers than with centralized servers—even highly scaled ones.
Improved website security and availability
Cybercriminals launch distributed denial of service (DDoS) attacks to harass or penetrate organizations’ digital defenses. CDNs offer inherent DDoS protection by multiplying the points of access cybercriminals would have to breach.
Many CDNs support additional security enhancements, such as web application firewalls (WAFs), to protect web apps.
Control of access and performance in different regions
If you have a dispersed audience, where some locations are busier than others, strategically deploying CDN servers can enhance your web performance in high-traffic regions and automate responses to spikes in demand. Conversely, you can also configure CDNs to limit access in particular areas.
Disadvantages of CDNs
While CDNs offer many advantages, they do have a few drawbacks, including:
Cost
CDNs aren’t cheap, and expenses include setup charges and ongoing operational costs tied to data transfer volumes that can become overwhelming if you haven’t budgeted for them.
Geography
Be careful about your CDN infrastructure location. Poor geographic alignment will reduce performance and content availability. To address this issue, some organizations use multiple CDNs with different footprints.
Complexity and support
A third-party CDN adds complexity to your website infrastructure and can complicate systematic troubleshooting exercises with an additional layer of customer support technicians.
Local restrictions
Some countries and local organizations block access to CDN-hosted content, which can negatively affect your website’s reach.
Why CDNs are essential for online businesses
There are multiple reasons why ecommerce business owners should include a CDN in their website infrastructure.
The impact of CDNs on SEO
Content delivery networks improve site performance in search results because:
- CDNs improve website speed: CDNs improve time to first byte (TTFB)—a web speed metric and known ranking factor in Google’s algorithm. Fast-loading websites improve the user experience and cultivate trust in the search engines that send users to them.
- CDNs improve website performance: Most CDNs offer video and image optimization services that reduce file sizes without compromising quality, further optimizing for speed and SEO.
- CDNs keep your site accessible: Crawlers regularly browse websites to index pages and determine their rank. Distributed CDNs will reroute traffic to another server if one goes down, ensuring your site is always accessible to crawlers and customers.
Alt text: Chart showing the factors that impact time to first byte on mobile and desktop.
User experience benefits
Website users won’t wait for a site to load. Just a two-second delay can increase bounce rate by 32%.
Plus, even if your main site loads reasonably fast, a CDN will still reduce wait time when visitors view data-heavy elements like videos and images. While bad load times lead to bounces, good ones can cultivate engagement.
Future trends in CDN technology
When CDN technology hit the scene in the late 1990s, big corporate websites and business applications were the primary use cases. Back then, the technology was new, expensive, and only worked for static content. The internet has come a long way since then.
CDN technology has evolved to include trends such as:
- Edge computing, which uses servers at the “edge” of a network so they’re as close to end users as possible.
- Serverless architecture, which relies on cloud-based CDNs. Since CDNs in the cloud only pay for the cloud space they use—rather than maintaining large, physical servers—the savings trickle down to customers.
- Artificial intelligence, whereby CDN service providers use AI and machine learning to predict traffic patterns. This can improve website performance by optimizing server request routing.
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What is CDN FAQ
Can a CDN help with SEO?
A CDN helps with SEO by improving page load speed, user experience, website security, and uptime, and by reducing bandwidth costs—all valuable factors for SEO.
How do I set up a CDN for my website?
Shopify uses a CDN backed by Cloudflare, one of the leading global CDN providers. Entrepreneurs who use Shopify to host their ecommerce websites receive automatic CDN setup.
Can I use multiple CDNs at the same time?
Yes, you can use multiple CDNs simultaneously. A multi-CDN strategy can improve uptime by rerouting requests to a user’s nearest server, which also enhances site load speeds.