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What is Multi-CDN and how does it work?

Industry Tips
August 11, 2023
Building commercetools Extensions

What is Multi-CDN and how does it work?

CDN comes with its own sets of issues to as it becomes a single point of failure & relying on a single Content Delivery Network (CDN) exposes an online content provider to the risk of degraded performance and outages. Netflix is reported to have three different CDN providers.

A multi-CDN strategy allows a content provider to share traffic between two or more providers to mitigate the risks of issues with any individual provider. Be it micro-outages, peak-hour performance degradation or other issues, having alternatives (multi CDN) allows content providers to protect their end-users against poor user-experience and its impact caused by a single CDN.

There are a small number of highly capable CDN providers in the market today that can be combined to create an effective multi-CDN architecture. The benefits of a Multi-CDN strategy are:

1) Eliminate Single Point of Failure

The main benefit of adopting multi CDN is that no single point failure can halt all the activities on your websites. When one CDN provider experiences an outage, Multi CDN automatically routes web traffic through another provider. Web content delivered by Multi CDNs is not affected by traffic spikes or fluctuations.

2) Increased Geographical Presence

Multi CDN also helps companies leverage more POPs they were not initially serving by leveraging different CDN providers in those regions. This helps companies deliver a consistent user experience to all the customers around the globe.

3) Divide Traffic as per strength of CDNs

All CDN are not alike, and they have different strengths with respect to Geography or asset class, etc. Routing the traffic with that knowledge through the CDN helps leverage the best of the best.

4) Optimized Model – Select best model for various content

Opting for multi CDN gives companies higher control over their costs. Businesses can focus on critical features and offerings and look for the best model to deliver content. For example, they can use different CDN providers for static and dynamic content. This flexibility and control allow them to go to providers who provide the same performance but for a lower rate, optimizing their whole model.

The increase in video streaming, video gaming, and video calling related internet services like Zoom, MS Teams, etc., put a considerable load on the networks that rely on CDN to reach all their users. So, when these infrastructure providers fail, they trigger a domino effect, taking down many websites, applications and other services with them. The failures in recent times reveal the vulnerability of the infrastructure. The only way to reduce the occurrences of these incidents is to increase resilience by having a diverse network of CDN providers.

Gotchas – Things to watch out in a multi-CDN approach

While multi CDN approach has its benefits, there are some limitations to it. Some CDNs for example provide front-end-optimizations which leads to content being non-transferable to a different CDN provider. Cache strategies across different CDN providers should be reviewed to be aware of the differences and inconsistencies that can lead to broken pages as certain CDNs cannot update their caches in sync.

How to adopt multi-CDN on your digital property?

Multi-CDN approach can be implemented on any site using DNS. Some DNS systems like Azure Traffic Manager, AWS Route 53, Google Cloud DNS and other DNS providers have varying levels of capability to dynamically decide on different name resolution based on performance or availability of different network endpoints. In this case these endpoints are of different CDN networks. DNS based multi-CDN approach is easy to implement and is agnostic of the CDN providers making it easier to adopt.

Thus, to opt for multi-CDN setup is a proactive step that eliminates the need for reactive ones later. We at Nitrogen implement effective multi-CDN strategies.

Talk to our experts to devise a Multi-CDN strategy for your eCommerce website.