CDN Load Balancing

CDN Load Balancing

Picture a bustling highway system where data are vehicles. Where one lane gets congested, traffic needs to be efficiently redirected to keep everything moving. This is the essence of CDN Load Balancing - managing data traffic across various routes, represented by multiple CDN vendors, to prevent digital gridlock. 

That system is CDN Load Balancing, but what does the term actually stand for? And how does it help you supercharge your website to success? Let’s talk about this and more, in the article below:

What is CDN Load Balancing?

In the bustling lanes of the internet Content Delivery Networks (CDNs) play a critical role. They’re the heart and soul, ensuring data gets to its destination fast and efficiently, contributing to a seamless online experience. 

Now, imagine a scenario where you have multiple networks of servers (i.e, multiple CDNs) that can share the burden of carrying a hefty load of traffic. That’s where CDN Load Balancing steps in. 

To put it simply, CDN Load Balancing is a robust method employed to distribute network traffic across multiple Content Delivery Networks. 


How does CDN Load Balancing Work?

Aptly named, CDN Load Balancing works by balancing the “load” or the number of end users across a network of CDNs. 

Let’s dissect this concept step by step:

1. DNS-Based Load Balancing

This is the most popular method of CDN load balancing. Here's how it works:

Step #1: DNS Resolution

The process starts when an end user wants to access content on a website. The user's device first performs a DNS resolution to identify which CDN the request should be sent to.

Step #2: CDN Receives the Request

Upon determining the appropriate CDN via DNS, the user's device sends the request directly to the chosen CDN. The CDN then intercepts this request.

Step #3: Content Delivery

Rather than allowing the request to travel all the way to the origin server, which might be located on the other side of the world, the CDN delivers the data from a location closer to the user. This ensures content is delivered rapidly and efficiently.

2. Client-Side Based Load Balancing

This method doesn't rely on the CDN for decision-making. Instead, decisions are made on the client's side. Here are its attributes:


  • Faster Reaction to Rebalance: Changes in traffic distribution can be addressed more swiftly.
  • Better Granularity of Traffic Split: Offers a more refined control over how traffic is distributed.
  • Cost-Effective: Can be cheaper in the long run compared to DNS-based solutions.


  • Lack of Transparency: It requires a proprietary solution on the client's side, which might not always be transparent.
  • Higher Implementation Effort: It demands more effort in terms of implementation and maintenance.

Benefits of CDN Load Balancing

Understanding the workings of CDN Load Balancing service inevitably leads to the realization of its several benefits. Let’s review each of them in detail:

  • Enhanced Performance: By distributing traffic, CDN Load Balancing reduces the burden on individual CDNs, allowing them to perform optimally. 
  • Increased Reliability and Availability: In the unfortunate event that one CDN fails or is experiencing local outages, CDN Load Balancing can quickly reroute the traffic to the other active CDN. 
  • Cost Savings: By selecting the best combo of cost-effectiveness, and performance, organizations can reduce costs, and optimize their delivery speeds - selecting the best CDN provider for each geographical location. 

Best Practices for CDN Load Balancing

Implementing CDN Load Balancing effectively requires adherence to a few best practices:

Practice Explanation
Online Monitoring Imagine having security cameras (known as "synthetic checks") and feedback forms from real visitors (called "Real User Monitoring" or RUM). These tools help check how well different delivery services (CDNs) are performing. If one CDN is slow or not working, we'll know quickly and can send users to a better-performing one.
Managing Multiple CDNs This is like having a central control room that watches over several delivery services (CDNs). The control room ensures that the user's requests (like wanting to see a webpage or video) are spread out evenly among the CDNs, so no single CDN gets overwhelmed.
Uniform Security and Traffic Rules Instead of different rules and security checks for each delivery service (CDN), this practice sets one standard set of rules and checks that all CDNs follow. This makes sure that every CDN is equally safe and follows the same guidelines, simplifying management and boosting safety.


In conclusion CDN Load Balancing ensures your CDN keeps up and running, even when one of them is down. In the fast-paced, ever-evolving internet landscape, the efficiency, reliability, and performance offered by CDN Load Balancing are not just valuable – they’re essential!

Published on:
December 28, 2023
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