**Definition:**A content delivery network (CDN) is a collection of distributed servers located across the globe that store files accessed by website visitors. Web content transmitted with the assistance of a CDN is delivered according to users' geographic locations, the content delivery server and the website's origin.
CDNs enable ecommerce websites to quickly deliver content such as images and other files, regardless of bandwidth (traffic levels) or the user's location. Without CDNs, load times for ecommerce stores would be a considerably longer for users hundreds or thousands of miles away from the host servers (such as international customers for US-based stores).
CDNs and Location
A user's geographical proximity to the CDN server dictates how fast the content is delivered. Those who are located closest to the server will receive content quicker than those who are positioned further away. Aside from delivering content, CDNs also guard against significant spikes in web traffic that would otherwise cause significant load times or even server crashes.
How CDNs Work
A website visitor's request to view online content is handled by the nearest server. The CDN's role is to:
Copy the requested website's pages to a server network dispersed along a number of different geographic locations.
Cache the website's contents and redirects the user's request from the initial site's server to the CDN closest to him.
Deliver the cached content. The CDN communicates with the initial server to transfer content that was not previously cached.
All of this takes place behind the scenes, outside of the user's view. A user will only know that a CDN is accessed if there is a difference between the delivered URL and the requested URL.
Why ecommerce stores rely on CDNs
Interactions between businesses often rely on CDNs, as do businesses that serve online content to customers. Ecommerce stores serving a global audience utilize CDNs to ensure that all customers have a pleasant user experience, regardless of location.
CDNs are used for applications beyond ecommerce, including catalyzing video, games, voice, mobile content etc. Websites that feature videos or other large media files generally utilize a CDN. In a nutshell, CDNs are critical to providing lightning-quick access to web content. If CDNs did not exist, users would be loading files from across the country or the world rather than accessing them through nearby servers.
Ecommerce platforms such as Bigcommerce come equipped with CDNs so customers from anywhere in the world can access a store without interruption.