A CDN (Content Delivery Network), also known as a Content Distribution Network, is a network of geographically distributed and interconnected servers that cache Internet content to accelerate delivery.
The primary goal of CDNs is to improve performance of web hosting services
by reducing the time it takes to transfer content-rich media to the user's Internet-connected devices. Its architecture is also designed to minimize network latency, which is often caused by transporting traffic over long distances across multiple networks.
The server closest to the user is identified, and content is delivered from this edge node CDN server—thus increasing the delivery speed and quality for the end-user. Content is replicated to provide as many users as possible with identical content during peak usage.
A Content Delivery Network (CDN) is a network of geographically dispersed servers in different data centres
that enables faster web performance by locating copies of web content closer to end-users, enabling more rapid delivery of content to their mobile devices.
Removing latency has become increasingly important due to the need to deliver content-rich media such as video, audio and video - to a growing number of mobile devices.
The servers of the CDNs are located at the so-called network edge, where the connection speeds to end-users are faster.
CDNs servers store the content-rich media such as video, audio, and video content - on host servers.
How quickly the content is delivered depends on the geographical proximity of the user to the CDN servers. The web content transmitted using a CDN delivers higher speeds than the web content on the host server.
A CDN enables developers to deliver high-bandwidth content to users by caching content for them at strategically placed physical nodes around the world.
CDNs do minimize latency, but dynamic content cannot be cached, and the point of presence (POP) must be close to the end-user for fast loading times. Some scripting languages do offer caching solutions for dynamic content, such as PHP
and OPCache. This saves the output of the PHP query if the same query is run and no updates are found. Other software such as NGINX
can also provide web caching
, which saves the output of PHP into a html file which can skip the dynamic loading of the page, which can then be pushed out to a CDN.
While CDNs are an excellent solution for most websites looking for speed improvements, not every site needs one. For example, a smaller site with fewer visitors, or a hyper-local club website would not benefit from a CDN, but a global business with sales around the world would.
CDNs now serve a large portion of Internet content, including streaming media, real-time data streaming, video, audio, and video content. This technology is becoming increasingly important as websites offer e-commerce and other applications that matter, such as social media and online shopping.