CDN Explained?
A content delivery network (CDN) refers to a geographically distributed group of servers which work together to provide fast delivery of Internet content.
A CDN allows for the quick transfer of assets needed for loading Internet content including HTML pages, javascript files, stylesheets, images, and videos. The popularity of CDN services continues to grow, and today the majority of web traffic is served through CDNs, including traffic from major sites like Facebook, Netflix, and Amazon.
The primary benefits for most users can be broken down into 4 different components:
Improving website load times – By distributing content closer to website visitors by using a nearby CDN server (among other optimizations), visitors experience faster page loading times. As visitors are more inclined to click away from a slow-loading site, a CDN can reduce bounce rates and increase the amount of time that people spend on the site. In other words, a faster a website means more visitors will stay and stick around longer.
Reducing bandwidth costs – Bandwidth consumption costs for website hosting is a primary expense for websites. Through caching and other optimizations, CDNs are able to reduce the amount of data an origin server must provide, thus reducing hosting costs for website owners.
Increasing content availability and redundancy – Large amounts of traffic or hardware failures can interrupt normal website function. Thanks to their distributed nature, a CDN can handle more traffic and withstand hardware failure better than many origin servers.
Improving website security – A CDN may improve security by providing DDoS mitigation, improvements to security certificates, and other optimizations.
How does a CDN work.
At its core, a CDN is a network of servers linked together with the goal of delivering content as quickly, cheaply, reliably, and securely as possible. In order to improve speed and connectivity, a CDN will place servers at the exchange points between different networks.
These Internet exchange points (IXPs) are the primary locations where different Internet providers connect in order to provide each other access to traffic originating on their different networks. By having a connection to these high speed and highly interconnected locations, a CDN provider is able to reduce costs and transit times in high speed data delivery.
Reliability and Redundancy – How does a CDN keep a website always online?
Uptime is a critical component for anyone with an Internet property. Hardware failures and spikes in traffic, as a result of either malicious attacks or just a boost in popularity, have the potential to bring down a web server and prevent users from accessing a site or service. A well-rounded CDN has several features that will minimize downtime:
Load balancing distributes network traffic evenly across several servers, making it easier to scale rapid boosts in traffic.
Intelligent failover provides uninterrupted service even if one or more of the CDN servers go offline due to hardware malfunction; the failover can redistribute the traffic to the other operational servers.
In the event that an entire data center is having technical issues, Anycast routing transfers the traffic to another available data center, ensuring that no users lose access to the website.
