Why do customers use 2 CDN when Adobe is already providing one for Cloud?

[learningNeverStops]

Hello,

What are the technical or business use-case for which customers use 2 CDN (1 Adobe + 1 customer managed CDN)?

Doesn't it cause more complexity in handling cache?

[HrishikeshKa]

Hi @learningNeverStops ,

Customers may opt for multiple CDNs, including Adobe's and a customer-managed one, for several reasons, both technical and business-oriented.

1. Redundancy and Reliability: Relying on a single CDN provider, even if it's a reputable one like Adobe, poses a risk. If there are any outages or performance issues with Adobe's CDN, having a backup CDN ensures continuity of service. This redundancy enhances the overall reliability of content delivery.

2. Performance Optimization: Different CDNs may excel in delivering content to specific geographic regions or under certain network conditions. By using multiple CDNs, customers can optimize content delivery performance by directing traffic to the CDN that provides the best performance for each user's location or network conditions.

3. Cost Management: While Adobe may provide a CDN as part of its cloud services, using a customer-managed CDN might offer more flexibility in terms of pricing structures. Customers may choose to use their CDN for specific types of content or for traffic in certain regions to better manage costs.

4. Control and Customization: Customer-managed CDNs offer greater control and customization options compared to using a CDN provided by a third-party service like Adobe. This control can be particularly valuable for businesses with specific security requirements, content delivery needs, or regulatory compliance concerns.

5. Content Delivery Requirements: Some businesses may have specialized content delivery requirements that cannot be fully met by Adobe's CDN alone. By using a combination of CDNs, they can tailor their content delivery strategies to meet these specific requirements more effectively.

While using multiple CDNs does introduce complexity in cache handling and content delivery management, this complexity can be mitigated through careful planning, implementation of appropriate caching strategies, and the use of advanced CDN management tools. Content delivery networks typically offer features and tools to help manage caching, such as cache invalidation mechanisms, cache purging, and cache control headers, which can help minimize the impact of using multiple CDNs on cache management. Additionally, content delivery management platforms or services can provide centralized control and monitoring capabilities to streamline the management of multiple CDNs.

Reference:https://experienceleague.adobe.com/en/docs/experience-manager-cloud-service/content/implementing/con...

[Madhur-Madan]

Hi @learningNeverStops ,
Below mentioned are the few reasons why Dual CDNs are used

• Legacy Integrations: Some clients may have existing CDNs that are deeply integrated into their infrastructure. Transitioning away from these legacy systems can be challenging.
• Custom Requirements: Clients might have specific requirements that go beyond what AEM’s CDN offers. In such cases, they may choose to use their own CDN alongside AEM’s.
• Load Distribution: Dual CDNs can help distribute the load across different networks, ensuring redundancy and fault tolerance.
• Geographic Coverage: Clients may use their own CDN to optimize content delivery in regions where AEM’s CDN might have limitations.
• Complex Use Cases: Certain applications with intricate content delivery needs may benefit from a combination of CDNs.

If a client opts for dual CDNs, they must configure their CDN to work with AEM as a Cloud Service. Load testing ensures that the combined CDN setup performs well before going into production.

Thanks and Regards,
Madhur

[kautuk_sahni]

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[EstebanBustamante]

Hi @learningNeverStops ,

Beyond the reasons already shared, I think it has more to do with what the client feels comfortable working with. Sometimes a client is used to a specific CDN provider or has several customizations on top of that CDN. At least, that's the main reason I've encountered in my experience. Additionally, with a custom CDN, you have more control to fine-tune it to your needs. Although this has changed recently with Adobe CDN, the support and flexibility you can have with your own CDN can still be greater.

Hope this helps.

[Raja_Reddy]

Hi @learningNeverStops 
https://experienceleague.adobe.com/en/docs/experience-manager-cloud-service/content/implementing/con... 

There could be several reasons why customers use two Content Delivery Networks (CDNs) instead of relying solely on Adobe's CDN.

1. Performance Optimization: Customers may use a second CDN to optimize the delivery of content to their end-users. By using a second CDN, they can leverage the benefits of both CDNs to improve the performance of their website or application. For example, they may use Adobe's CDN for delivering dynamic content and their own CDN for delivering static content.

2. Cost Optimization: Customers may use a second CDN to optimize their costs. By using their own CDN, they can potentially reduce their costs for delivering content, especially if they have a high volume of traffic. They may also be able to negotiate better pricing with their own CDN provider.

3. Security and Control: Customers may use a second CDN to have more control over the delivery of their content and to enhance their security posture. By using their own CDN, they can implement additional security measures, such as DDoS protection, web application firewalls, and content filtering.

[sarav_prakash · Accepted solution]

Honestly, adobe CDN is bad.. While fastly provides basic cdn functionality, NO options to customize or extend. Any extra functionalities, BYOC, bring your own cdn. Plus there are product bugs, cdn issues, noway to fix them. I documented one cdn issue I faced

https://medium.com/@bsaravanaprakash/geolocation-using-aem-cloud-service-works-great-except-it-doesn...

The most basic CDN feature every org wants is - edge redirector, to manage custom redirect rules at fastly to manage traffic, nopes. We had requirements to run certain headless functions from cdn as edge functions; needed custom cache purge strategy; edge-side includes; many many requirements,  RIP. 

CDN is the closest application to the browser, we can do magic. Cloudflare is growing very strong with incredible options. Just AEM alone banished with fastly leaving no choice. 

Many orgs manage thier own CDN since AEM is not thier only web option. All application like salesforce, SAP Hybris, MFEs, and last AEM, all play behind single custom CDN which orchestrates the traffic dance efficiently. Better to align to org cdn policy than getter married to adobe only option. 

[BrianKasingli]

Adobe wants to provide the best experience to their customers, and so this CDN layer is by default enabled for all AEMaaCS websites.

Disabling or configuring the Fastly CDN on your AEM as a Cloud Service (AEMaaCS) environment requires coordination with Adobe support, as Fastly is a key part of the infrastructure provided by Adobe to optimize delivery and performance. However, there are scenarios where you might need to bypass or configure Fastly for specific requirements.

For the full documentation of this feature, checkout Adobe's official website documentation: CDN in AEM as a Cloud Service | Adobe Experience Manager