What is a content delivery network?

A content delivery network (CDN), is a distributed network of servers across different locations that ensure efficient content delivery on websites around the globe. High-profile websites that require continuous real-time responses implement CDN for better user experience. For example, Facebook has various data center points worldwide where its data is stored to achieve the best response and page loading speed regardless of geographical location.

What is an origin server?

It is a server that hosts the original version of the data. Initially, all the users directly request the origin server, but when we add CDN, it divides the requests to other data-storing resources. CDN protects the website from malicious attacks by acting as a protective layer on the origin server.

What is an edge server?

Edge servers are what are used by the CDN as the data-storing resources to distribute the origin server request and reduce its workload. The user requests are diverted to the edge servers that have replicated data of the origin server. These servers are located in different geographical regions, and the overall website traffic is divided among them to lower the loading time and provide a good user experience.

How CDN works?

Let's take an example of an e-commerce website accessed globally to understand how CDN works. When a user from location A sends a request to the server, it is received by the nearest edge server in location A. That edge server then forwards the request to the origin server and gets the response which is then sent to the user as a response and cached for future requests. Consequently, when another user sends the same request to that edge server, it can respond without contacting the origin server.

Multiple edge servers distributed across the globe cache the data and information received by the origin server and handle the user requests in their respective areas. This divides the traffic of the origin server on multiple servers and provides an efficient real-time service.

Note: Cache is different from CDN as it is a local storage method to store frequently used data whereas CDN is a geographically spread network of servers designed to deliver the website content to users.

Benefits of CDN

CDN is adopted by all major websites, especially those that cater to a larger audience and require good real-time interactivity with the user. It has various benefits; let's discuss a few of them.

Improve performance

An efficient CDN provides a good user experience by lowering latency and helping the server combat barriers and delays. The latency rate can commonly increase due to:

Propagation delay when data is traveling from one node to the other
Storage blockage that causes delays in reading data
Network congestion mostly during the high usage times
Long-distance traveling of data

CDN divides the server traffic, provides edge servers at different locations, and improves the request and response flow overall.

Optimize content distribution

Redundancy is important in keeping the content accessible to combat downtime and interruptions. CDN distributes the traffic over multiple servers that contain redundant data that is used to respond to user requests more efficiently.

Reduce bandwidth consumption

Bandwidth cost is one of the significant expenses during web hosting which can be reduced by handling traffic through multiple points. CDN caches the data at the edge servers and divides the origin server traffic at multiple points.

Improve website security

There is a high probability of experiencing DDoS attacks when the web requests are catered to through a single server. This can result in multiple users and bots extensively increasing the traffic for days to crash the website and make it inaccessible. CDN helps to make the origin server difficult to track by adding an edge server as a protective layer and deflects the traffic from it. Moreover, the SSL certificates are also continuously refreshed for data transmission encryption to keep the connection secure.

CDN service providers

CDN is being implemented by major applications to optimize their content delivery and real-time user experience. There is a continuous increase in demand to find trusted CDN solutions, and many prominent CDN service providers are there that cater to a large number of customers. Some of the major providers are as follows: