Choosing the Right Azure CDN Solution

In today’s digital landscape, delivering content quickly and efficiently is paramount. Azure CDN (Content Delivery Network) and FrontDoor are powerful services provided by Microsoft Azure that help optimize content delivery, enhance performance, and improve user experience. With multiple options available, it’s essential to understand their features and use cases to make an informed decision.

Azure CDN and FrontDoor offer a lot of overlap in terms of features. In this blog, we will delve into the various Azure CDN and FrontDoor options and discuss their suitability for different scenarios.

Azure CDN Options

Azure CDN offers three main options to meet various performance, scalability, and content delivery needs:

1. Azure CDN Standard from Microsoft (classic)
2. Azure CDN Standard from Edgio
3. Azure CDN Premium from Edgio

Each option provides distinct features and capabilities, allowing you to tailor your content delivery strategy based on your specific requirements.

Note: Azure used to provide “Azure CDN Standard from Akamai” options as well, but it has recently been discontinued as Microsoft and Akamai have decided not to renew their contract.

1. Azure CDN Standard from Microsoft
   Azure CDN Standard from Microsoft is a cost-effective option that leverages the Microsoft global network. It provides broad coverage and high availability, making it suitable for delivering static content, such as images, videos, and documents.
   This option is ideal for scenarios where cost optimization and wide geographical reach are essential.
2. Azure CDN from Edgio
   Azure CDN from Edgio combines the power of Edgio’s technology (formerly Limelight Networks) with Azure’s scalability and reliability. There are two offerings under this option:

• Azure CDN Premium from Edgio
• Azure CDN Standard from Edgio

Azure CDN Standard from Edgio provides features similar to those of CDN Standard by Microsoft. The premium option offers enhanced security features, real-time analytics, and advanced caching capabilities. This option is recommended for mission-critical applications that require robust security, real-time insights, and advanced customization options.

Azure FrontDoor

Azure FrontDoor is a more comprehensive service than Azure CDN. It includes a CDN, a web application firewall (WAF), and global load balancing and offers advanced traffic management capabilities, including routing, SSL termination, and application acceleration. This can help you to protect your applications from common web attacks, improve the performance of your applications, and ensure that your applications are always available.

Azure FrontDoor offers three different options:

1. FrontDoor Classic:
   This Frontdoor offering provides limited features, including basic routing, dynamic site acceleration, and some security options such as Web Application Firewall (WAF) Integration, Custom Domain HTTPS Support, etc. This uses an older “Microsoft.Network” resource provider, and it is recommended to use Standard and Premium FrontDor offerings as they are deployed using the latest “Micrpsoft.Cdn” resource provider.
2. FrontDoor Standard:
   The FrontDoor Standard option is a good choice for most workloads. It offers advanced routing rules, caching configurations, load balancing, Web Application Firewall (WAF), and DDoS protection.
3. FrontDoor Premium:
   The FrontDoor Premium option is good for high-traffic workloads or workloads requiring low latency. It offers all of the features of the FrontDoor Standard option, plus additional features such as support for streaming media, advanced Security, complex routing, and real-time traffic management.

Common Features

Let’s first check what are the common features provided by all the above options we discussed. Here is the list of common features:

• In the content delivery category, all of them support Static file delivery.
• The below features are available in the Domains and Certificates category:
  1. HTTPS support
  2. Custom domain HTTPS
  3. Bring your own certificate
  4. Supported TLS Versions 1.1 and 1.2.
• Below are Caching features are support:
  1. Query string caching
  2. Cache management (purge, rules, and compression)
  3. Cache behavior settings
• The list of feature supported under the Routing category are:
  1. Origin load balancing
  2. Path-based routing
  3. Rules engine
  4. IPv4/IPv6 dual-stack
  5. Origin Port
  6. HTTP/2 support
  7. Geo-filtering
  8. DDOS protection
• Analytics and Reporting
  1. Basic Monitoring
  2. Raw logs – access logs and WAF logs
  3. Easy integration with Azure services, such as Storage and Web Apps
  4. Management via REST API, .NET, Node.js, or PowerShell
  5. Compression MIME types
  6. Compression encodings: gzip only.

Major differences in Offerings

• Dynamic site delivery is one of the crucial features that is supported by all offerings except Azure CDN Standard Microsoft.
• Custom Web Application Firewall (WAF) rules are supported by all Front Door offerings.
• TLS 1.3 is supported by Azure CDN Standard and Premium versions of Edgio, making it the only choice for websites using TLS 1.3.

  Asset preloading and Fast purge are some essential features supported by both versions of Edgio.

• Server variables are supported by Front Door Standard and Premium offerings. The variables provide access to structured information about the request and its context. These variables can be used in Rule Set match conditions and actions to control traffic routing, content manipulation, and other behaviors.
• Regular expressions in the rules engine are  Front Door Standard and Premium and Azure CDN Premium Edgio.
• URL redirect/rewrite are not supported by Azure CDN Standard Edgio only.
• Azure CDN Standard Edgio does not support customizable, rules-based content delivery engines and mobile device rules. Azure CDN Standard Microsoft and Azure CDN Premium Edgio use Standard rules engine to provide this feature.
• Private link connection to the origin (by bypassing the Public network) is offered by only Front Door Premium.
• Token-based authentication is supported by Azure CDN Premium Edgio only.
• Advanced analytics/built-in reports are supported by all Frontdoor and Premium Edgio offerings of Azure CDN.
• Compression encodings: “brotli” is supported by all except Azure CDN Standard Edgio. “Bzip2” is supported by both Edgio offerings of Azure CDN.
• Managed Identities with Azure Key Vault is supported by Front Door Standard and Front Door Premium.

Choosing the Right Solution

Now that we have explored the Azure CDN and FrontDoor options let’s discuss their suitability for different use cases:

Static Content Delivery

If your primary requirement is to deliver static content efficiently for low-traffic applications, Azure CDN Standard from Microsoft is a cost-effective choice. Its broad coverage and high availability ensure your content reaches users worldwide with minimal latency.

Classic Frontdoor could suit simple needs like basic routing and content acceleration for static websites in limited regions.

For an average monthly traffic of 100 TB through each service, assuming the website consists mainly of images and scripts with an average file size of 100 KB. The estimated monthly cost for Azure CDN Standard is ~2k, whereas for Classic Front Door, it is 2.7k. This would give a high-level cost difference between the two offerings.

Enhance caching and Global Private Peering

Azure CDN Standard from Edgio could be ideal for businesses needing enhanced caching, private peering, and slightly more complex content delivery scenarios. This is more affordable than Front Door Standard due to its slightly simpler capabilities.

Demanding Application and Streaming Media

For applications that involve Live and on-demand video streaming, Dynamic content delivery, Large file downloads and Complex content delivery scenarios, Azure CDN Premium from Edgio offers superior video streaming optimization with features like adaptive bitrate streaming and video packaging caching and acceleration capabilities providing high traffic volumes and ensure optimal performance.

Global Traffic Management and Granular Control on security

In addition to CDN services, Azure FrontDoor Premium is an excellent choice if you need advanced traffic management and Global Reach and Performance. An extensive network of edge locations and advanced routing algorithms provide low latency. Integration with Azure Functions for dynamic content generation and Azure Active Directory for authentication make it a more versatile offering.

The Azure FrontDoor Standard offering becomes preferred if bot protection and Private Peering are not required.

Conclusion

Choosing the proper Azure CDN and FrontDoor option is crucial for optimizing content delivery and enhancing user experience. By understanding each option’s features and use cases, you can make an informed decision that aligns with your specific requirements. Whether you need to deliver static content, handle dynamic workloads, or require advanced traffic management, Azure CDN and FrontDoor offer comprehensive tools to meet your needs. Evaluate your use case, consider the specific requirements, and select the most suitable option to achieve your content delivery goals.

Remember, Azure’s flexible and scalable infrastructure allows you to adapt and evolve your content delivery strategy as your application grows and user demands change.

References:
https://learn.microsoft.com/en-us/azure/frontdoor/front-door-cdn-comparison
https://learn.microsoft.com/en-us/azure/frontdoor/standard-premium/how-to-reports?tabs=traffic-by-domain