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Cloudinary’s Multi-CDN Approach: The Whole is Greater Than the Sum of Its Parts

A content delivery network (CDN) is a physically distributed infrastructure of interconnected points of presence (POPs) that cache content as close as possible to the end-user, thus offering the best performance and user experience.

CDNs also boosts content reliability by shielding websites from most of the traffic. Even if the original site goes down, its pages and a majority of the content, given that they are served by CDNs, would remain available to the audience.

However, supplying different types of content to an ever-growing number of end-users and geographies on versatile networks is an exceedingly knotty and tough task. Not surprisingly, therefore, CDNs are becoming more and more complex.

CDN providers abound, some of which are large and well established with impressive geographical reach and reliability. All you need to do is open an account and then “problem solved,” right?

Well … not quite. Because two important factors are at play:

  • CDN service outages are a fact of life. In fact, the volume of internet outages is on an incline and none of the major CDN suppliers has avoided significant outages costing customers many millions in lost revenue.  

Even though the CDN concept has been around for ages and several of the long-time providers have placed great emphasis on availability, issues are on the rise. The challenges of volume and complexity are on a steep incline. Always expecting the unexpected is a key premise that all good services live by, but as reality has proven time and again, unforeseen issues can’t be completely eliminated with the most prominent factors being power outages, bugs and human error, communication outages, and security-related issues. Consequently, any CDN, even the best, is likely to experience occasional blackouts, some of which can be severe.

A large majority of these failures are local and partial and are likely to be absent from your radar screen. Others are complete service stoppages that are splashed across the headlines. These outages not only directly impact site functionalities, such as sales transactions, but also indirectly damage your brand.

  • Service performance varies across geographical regions, networks and time. CDNs are structured differently with a diverse geographical and network presence. As a result, users in different locations with different internet providers on different communication mediums and technologies (landline, 3G, 4G, 5G, etc.) receive very different levels of service.

    Furthermore, providers have different strengths and weaknesses, which can change continuously as the load varies. For example, usage spikes on a specific CDN POP would cause a performance decline for users served by that POP. 

In partnership with multiple CDN providers, Cloudinary ensures a common facade, masking the complexities that stem from the differences described above. After all, different CDNs work very differently, offering common but also unique capabilities. By mediating many of these differences, Cloudinary has generated a common baseline of features around serving, invalidations, logging, and reporting. Cloudinary provides a long list of significant unique capabilities on top of the basic functionality provided by CDNs. Some of the most noteworthy include: 

  • Automatic format selection per the viewing device and browser.
  • Responsive media resizing. 
  • Support of SEO enhancements for serving media.
  • End-user authentication.
  • Automatic invalidation of cached data when needed. 

Through automatic detection of service availability and performance in various locations, Cloudinary can dynamically and efficiently select and route requests to the most performant CDN for different end-users worldwide. The result is joint availability and enhanced overall performance that are significantly superior to those offered by any individual CDN provider. 

The deep understanding and continuous cooperation with our top tier partner CDNs has enabled Cloudinary to define integrations that provide a common ground of functionality, bridging the significant differences between these top vendors.

That common ground for CDN functionalities has enabled Cloudinary to adopt a multi-CDN approach, and provide a solution through which Cloudinary acts as a single hub for CDN setup and delivery on top of multiple underlying CDNs, simplifying management and reducing room for error.

All configuration changes are made through simple automated procedures, which efficiently, automatically, and reliably propagate to all associated CDNs.

Different logs are automatically collected and processed, providing Cloudinary customers a coherent, non-fragmented understanding of the traffic and service level provided to their end-users, as well as reliable and automated error detection, regardless of the underlying providers. 

Cloudinary provides different variations of the multi-CDN service according to customer needs, but all Cloudinary customers enjoy some level of multi-CDN based redundancy, and have their content delivered over more than a single CDN.

Cloudinary provides a unique media delivery service that utilizes a combination of continuous service monitoring of multiple underlying top-tier CDN services, to provide significantly higher aggregate availability, better performance, and higher global reach than those provided by any single CDN solution. This eliminates the need to manage CDN delivery altogether for many of our customers, and simplifies administration for those who require more in-depth monitoring.

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