Multi CDN: 8 Amazing Benefits, Methods, and Best Practices

What Is Multi CDN?

A content delivery network (CDN) is a distributed network of servers that are designed to deliver content to users quickly and efficiently. The main purpose of a CDN is to reduce latency and improve the performance of websites and applications by caching and serving content from a location that is closer to the end user.

When a user requests content from a website or application that is powered by a CDN, the request is redirected to a nearby CDN server, which serves the content from its cache if it is available. If the content is not cached, the CDN server will retrieve it from the origin server and cache it for subsequent requests.

CDNs are commonly used to deliver a variety of content, including web pages, images, videos, and software downloads. By using a CDN, organizations can reduce the load on their origin servers and improve the user experience for their customers, regardless of their location or the type of device they are using.

This is part of a series of articles about website performance.

In this article:

• How Multi-CDNs Work
• CDN vs. Multi CDN: What Is the Difference?
• 8 Benefits of Multi CDN
• Multi CDN Implementation Methods
• Best Practices for Your Multi CDN Strategy

How Multi-CDNs Work

Multi-CDN systems enhance content delivery by distributing traffic across multiple CDNs within the network. The routing of traffic is determined by various factors, depending on the specific multi-CDN setup. Here are some commonly deployed strategies:

• Static DNS – This method involves setting up fixed DNS entries for each CDN in the multi-CDN framework. For instance, traffic for highspeedvideo.domain might be directed to one CDN, whereas static.downloads.domain could go to another CDN. This approach is straightforward but lacks automatic failover capabilities and does not consider cost or performance factors in routing decisions.
• Managed DNS – Adding an intelligence layer to static DNS configuration, managed DNS services introduce smart routing to minimize manual interventions and enhance fault tolerance. However, like static DNS, this method does not incorporate cost or performance variables in making routing decisions.
• Round-robin – This technique directs incoming requests to different CDNs sequentially. For example, in a setup with two CDNs, the first request goes to CDN-A, the second to CDN-B, then back to CDN-A for the third, and so forth. With weighted round-robin, traffic distribution can be biased, such as directing 50% of the load to CDN-A, 30% to CDN-B, and 20% to CDN-C in a three-CDN configuration.
• Geolocation – Using geolocation, multi-CDN systems choose the CDN located closest to the user’s geographical location for each request. This method aims to enhance performance by reducing latency.

Variable-driven load balancing – The most advanced and versatile multi-CDN strategy, this method leverages multiple factors such as cost, performance, location, weights, and other criteria. Though complex to configure, it offers significant benefits in terms of cost-efficiency and performance by making real-time routing decisions based on a comprehensive set of variables.

CDN vs. Multi CDN: What Is the Difference?

Multi CDN involves using multiple CDN providers to distribute content to end-users. Instead of relying on a single CDN provider, Multi CDN combines the resources of multiple CDNs to improve the reliability, performance, and resilience of content delivery.

The primary advantage of using Multi CDN is that it helps to ensure that content is delivered even if one of the CDN providers experiences an outage or slowdown. By using multiple CDN providers, content delivery is balanced across different networks, reducing the risk of congestion or failure in a single network.

8 Benefits of Multi CDN

Here are the main benefits of implementing multi CDN:

1. Improved reliability

Multi CDN helps to ensure that content is delivered even if one of the CDN providers experiences an outage or slowdown. By using multiple CDN providers, content delivery is balanced across different networks, reducing the risk of congestion or failure in a single network.

2. Better performance

By selecting the best CDN provider for a particular location or user, Multi CDN enables organizations to optimize content delivery and improve performance. This can lead to lower latency, faster page load times, and a better overall user experience.

3. Increased resilience

Multi CDN provides a fallback solution in the event of an outage or slowdown with one CDN provider, ensuring that content delivery continues without disruption. This helps to ensure that users can always access the content they need, even in the face of technical issues.

4. Global coverage

Multi CDN allows organizations to use the best CDN provider for each location, ensuring that content is delivered efficiently and effectively to users around the world. This is particularly important for organizations with a global customer base, as it helps to ensure that users have a consistent and high-quality experience, no matter where they are located.

5. Improved security

Multi CDN provides an additional layer of security, as multiple CDN providers can be used to distribute content, reducing the risk of a security breach. This is particularly important for organizations that handle sensitive information, as it helps to ensure that data is protected and secure.

6. Cost savings

By selecting the best CDN provider for each location, organizations can reduce costs and optimize their content delivery spend. This can be achieved by selecting a CDN provider that offers the best combination of performance, reliability, and cost-effectiveness for a particular location.

7. Enhanced flexibility

Multi CDN provides organizations with the ability to switch between CDN providers on the fly, ensuring that they can always use the best solution for their needs. This enables organizations to respond quickly to changes in their content delivery requirements, and to take advantage of new opportunities as they arise.

8. Improved scalability

Multi CDN enables organizations to scale their content delivery quickly and easily, providing the resources necessary to support rapid growth. This is particularly important for organizations that are experiencing rapid expansion, as it helps to ensure that their content delivery infrastructure can keep up with their growth.

Multi CDN Implementation Methods

DNS Load Balancing

This is a method of distributing content delivery across multiple CDN providers using DNS (Domain Name System) to direct traffic to the best CDN for a particular location. In this method, the DNS server acts as a load balancer, directing traffic to the best CDN provider for a particular location, based on factors such as network performance, availability, and cost.

Advantages of DNS load balancing:

• Simple to implement: DNS Load Balancing is relatively easy to implement and does not require a complex network infrastructure.
• Flexible: The load balancing decision can be easily changed based on real-time performance data.
• Scalable: DNS load balancing can be easily scaled to accommodate changing content delivery requirements.

Disadvantages of DNS load balancing:

• Limited control: DNS load balancing provides limited control over the content delivery process, as it is dependent on the performance of the underlying network infrastructure.
• Limited performance: The performance of DNS load balancing may be limited by the speed and efficiency of the DNS servers.
• Vulnerability: DNS load balancing can be vulnerable to security threats, such as Distributed Denial of Service (DDoS) attacks, which can disrupt the content delivery process.

Primary-Fallback Scheme

This is a method of distributing content delivery across multiple CDN providers, where one CDN provider is designated as the primary provider, and others are used as fallback providers. In the event of an outage or slowdown with the primary provider, traffic is redirected to one of the fallback providers, ensuring that content delivery continues without disruption.

Advantages of the primary-fallback scheme:

• Reliable: The primary-fallback scheme provides a reliable content delivery solution, as it ensures that content is always available, even in the event of an outage or slowdown with the primary provider.
• Simple to implement: The primary-fallback scheme is relatively simple to implement, and does not require a complex network infrastructure.

Disadvantages of the primary-fallback scheme:

• Limited control: The primary-fallback scheme provides limited control over the content delivery process, as it is dependent on the performance of the underlying network infrastructure.
• Inflexible: The primary-fallback configuration may not be ideal for all locations or user groups, leading to suboptimal content delivery performance.

Performance Data-Driven Load Balancing

This is a method of distributing content delivery across multiple CDN providers, based on real-time performance data. In this method, performance metrics such as network latency, throughput, and availability are used to determine the best CDN provider for a particular location, ensuring that content is delivered to users quickly and efficiently.

Advantages of performance data-driven load balancing:

• Optimal performance: This method provides the best possible content delivery performance, as it is based on real-time data about the underlying network infrastructure.
• Flexible: The load balancing decision can be easily changed based on changing performance data, ensuring that content delivery is always optimized.

Disadvantages of performance data-driven load balancing:

• Complex to implement: This method requires a complex network infrastructure and specialized knowledge to implement effectively.
• Increased costs: Performance data-driven load balancing may result in increased costs, as it requires the use of specialized hardware or software.

Turnkey Multi CDN platform

Turnkey multi CDN is a turnkey solution for distributing content delivery across multiple CDN providers, which is provided by third-party service providers. With turnkey multi CDN, the service provider manages all aspects of the multi CDN implementation, including the selection and integration of CDN providers, load balancing, and performance monitoring.

Advantages of turnkey multi CDN:

• Simplified implementation: This method simplifies the implementation of multi CDN, as the service provider takes care of all the technical aspects of the implementation.
• Improved performance: Turnkey multi CDN provides improved content delivery performance, as the service provider has expertise in selecting and integrating multiple CDN providers.
• Reduced costs: This method can result in reduced costs, as the service provider may be able to negotiate better pricing from CDN providers due to their volume of business.

Disadvantages of turnkey multi CDN:

• Limited control: The service provider has control over the content delivery process, and the user may have limited control over the configuration of the solution.
• Dependent on the service provider: Turnkey multi CDN is dependent on the performance and reliability of the service provider, which may result in a loss of control and visibility into the content delivery process.

Best Practices for Your Multi CDN Strategy

Group Content by Type

By grouping content by type, organizations can ensure that the most appropriate CDN provider is delivering each type of content. For example, static content, such as images and HTML pages, may be best delivered by one CDN provider, while video content may be best delivered by another. This helps to ensure that each CDN provider is delivering the type of content that they are best suited to handle, improving overall performance.

Institute Consistent Hashing of Your Working Set

Consistent hashing is a way of distributing content across multiple CDN providers in a balanced manner. It involves dividing the content into segments and then mapping each segment to a specific CDN provider, based on their strengths and weaknesses. This helps to ensure that the load is distributed evenly across the CDN providers, improving overall performance and reliability.

Establish Consistent Monitoring Parameters

To effectively manage a multi CDN implementation, it is important to have a consistent approach to monitoring performance. This includes monitoring the performance of each CDN provider, as well as the overall performance of the multi CDN solution. This helps to quickly identify and address any issues that arise, and to ensure that the multi CDN solution is functioning optimally.

Seek Feature Parity Across Providers

When selecting multiple CDN providers, it is important to consider not only the technical capabilities of each provider, but also to seek feature parity between providers, to ensure that the multi CDN solution provides a consistent level of functionality and performance.