A content delivery network (CDN) is a distributed collection of servers used to deliver content and media (such as web pages) faster to users spread across different regions. While we think of this globally, it also describes server setups catering to specific areas, such as North America or Europe.
Since application users are often globally distributed—and especially so for popular websites like YouTube—it's important to deliver content quickly from a server located nearby versus halfway across the world. This latter approach would add a lot of latency, reduce delivery speeds, impact reliability, and therefore degrade user experiences. CDNs also promote scalability by adding resilience during traffic spikes.
Content delivery networks closely mirror processes like package delivery. Shippers or eCommerce companies typically maintain fulfillment centers in various locations to expedite delivery by reducing transit times and distances. CDNs work using this same principle. Added mechanisms like caching further accelerate delivery for repeat website visitors, to name one example, by keeping an accessible copy of served data closer to the client.
How do content delivery networks (CDNs) work?
CDNs are formed by setting up clusters of servers (usually with a load balancer in front of each cluster, using a load balancing algorithm such as path hashing) in multiple strategically-placed datacenters.
When a client requests a resource, this request contains information (such as an IP address) that the CDN or load balancer can use to route them to the nearest available CDN server which has the requested content (via a method such as Global Server Load Balancing). Each of these servers will retrieve any requested content it doesn’t have from an origin server (or servers) to serve to future clients who request the same file.
As part of one's load balancing infrastructure, a CDN helps distribute requests efficiently across multiple servers, reducing loads on any one server. This cuts down on resource consumption and helps prevent outages—boosting uptime. Plus, features like minification and compression reduce data payload sizes, helping those packets traverse the network even faster while reducing bandwidth requirements.
Does HAProxy offer content delivery network (CDN) functionality?
Yes! HAProxy Edge is a globally-distributed application delivery network that enables improved application performance, reliability, load balancing, and security at massive scale. With over 15 global locations (and growing), HAProxy Edge provides a turnkey CDN experience to help applications run their best.
