A content delivery network (CDN) is a group of servers that are geographically distributed and help in the process of delivering website content to users. This content could be JavaScript files, sheets, videos, HTML pages, etc. With the increasing popularity of CDNs, more companies and websites are starting to utilize them, but this doesn’t mean they can’t still have flaws.
Websites experience downtime for many reasons, from hardware issues to DDoS attacks or CDN problems. One of the most common issues regarding a single CDN is a CDN outage. You can use a multi-CDN strategy to improve the website’s reliability, minimize outages, and utilize all the CDN benefits.
What is a Multi-CDN?
A multi-CDN strategy is a hosting strategy that uses more than one CDN provider to deliver website content, helping the website in many different ways, such as:
- Faster content delivery to the user
- Improved reliability of the webpage
- Faster caching of important content
Benefits of Multi-CDN
Compared to single-CDN, a multi-CDN has many benefits, from decreased latency to enhanced security features, faster speeds, and almost guaranteed uptime for web pages. Using a multi-CDN means that if one of the CDNs has an outage, another can take the load, and the website will still be running despite the issues with the server.
The benefits you can experience when using a multi-CDN include the following:
- Better Coverage: A CDN is a geographically placed group of servers. This means that depending on where the user is logging from, they might experience latency or loading issues because the performance of the CDN varies by geography, performing better in some regions than others. That’s why global organizations use the multi-CDN approach to hosting their websites. More servers are spread across many regions, lowering the latency spikes and providing a faster and better response to the users.
- Lowering the cost of service: The CDN providers have different pricing depending on the geographical region, volume, content, peak or non-peak hours of usage, etc. Using multiple CDNs at once will help you spread the traffic better across all the servers, lowering the usage of each one and, with that, giving you the best possible price at any given moment.
- Faster loading speeds: Using multiple content delivery networks means more servers will be spread across multiple regions. This means that no matter where the user accesses the website, they can use the nearest server to their current location, lowering the latency and increasing the website’s loading speeds.
- Security: If a CDN server gets compromised, this might lead to hundreds, or even thousands, of websites being taken down. Using a multi-CDN approach means that even if one of the CDN providers gets attacked, the others can take the load because it’s rare for an attacker to take down more than one CDN provider simultaneously.
- Upgraded availability: While large companies and websites usually use CDNs, they have limited space. This means the server might get overwhelmed if there is a large peak in traffic. The multi-CDN approach will easily solve the problem by diverting the traffic to another CDN.
- Flexible networks: With the multi-CDN strategy, businesses can be more flexible. This helps them improve their websites, expand their global coverage, give more and better functionality to their web pages, etc. They can always switch between different CDNs, depending on their needs and addressing different circumstances.
Drawbacks of Using Multi-CDN
No tool is perfect, and some of the drawbacks of using a multi-CDN include:
- Complicated configurations: When using a multi-CDN strategy, you must ensure that all CDN providers use the same configurations. For example, all load balancing and routing settings must be the same across all CDNs.
- Need for experts: You need to have the technical knowledge on how to integrate multiple CDNs into your website to hire experts so they can manage the strategies.
- Performance measuring: While all the CDNs that are being used will come with performance logs, they will all need to be monitored, compared, and analyzed separately.
Methods of Routing for Multi-CDN
There are multiple approaches to how a multi-CDN handles a website’s load. Let’s look at some of the most common methods for multi-CDN management.
Load Balancing
This method allows different servers to handle different amounts of traffic, depending on several traffic routing rules. This means you can allocate traffic depending on your business needs and improve cache rations while the traffic gets divided between the different CDNs.
Let’s look at some of the most common traffic routing strategies for multi-CDNs.
- Round-robin: You can set the CDNs so that they take turns handling the load, which means it will be spread across all working servers. This method doesn’t consider the user’s location, network availability, traffic load, etc.
- Weighted round-robin: this method works similarly to the previous one, but this time instead of equally disturbing the traffic to all the available CDNs, it prioritizes specific CDNs depending on the traffic load ratio. You can make one CDNs take half of the work while the other half gets split between multiple networks.
- Geo-location: as the name suggests, this method distributes traffic depending on the user’s location. The closest CDN will activate once someone visits a website, giving the lowest latency. The current user’s location can be tracked down to as close as city level.
Fallback Strategy
Some of the CDN providers are considering that unexpected large peaks in traffic are inevitable, leading to long downtimes. Some providers implement a primary-fallback strategy into their CDN networks to counter that. This means they add a CDN held empty until needed. If the primary CDN starts to have performance issues and the traffic is too much for it to handle, the fallback CDN starts to handle some of the traffic.
Data-Driven Load Balancing
This method closely resembles regular load balancing but takes it to the next level. Instead of handling the load by previously set routing rules, the decisions are made automatically based on real-time CDN usage data. This means the system will detect if one or more CDNs are overwhelmed by traffic, and some load will spread across other delivery networks. This ensures faster loading times, better routing performance, and better customer experience.
Geographic Load Spread
With the help of geographically splitting the load across multiple CDNs, websites can utilize servers to their full extent. There will be no latency caused by the distance between the user and the server, and the traffic will be spread according to the regional usage on the CDNs. This also helps websites use regional CDN providers, which helps lower costs and provides customers an excellent experience.
How To Implement Multi-CDN
You must take multiple steps to implement a CDN strategy on your website. Here are the three essential things that need to be done so you can start implementing the multi-CDN setup.
- Choose your CDN partners: Before creating a multi-CDN strategy, choose the providers you will use. They can be spread worldwide, have different numbers of servers, and have different availability for utilizing load. Additionally, it’s usual for CDN companies to focus on certain regions. Major US and European cities often have superior CDN performance due to the huge number of edge servers. Because of this, you must be extremely careful about who you pick when live broadcasting to particular regions, like China.
- Choose multi-CDN management: managing a multi-CDN strategy can be done differently. This includes configuration, engineering support, integration support, etc. Choosing the best solution for you will help you with traffic management and network routing. Managing several CDNs may be facilitated by a multi-CDN DNS provider or multi-CDN management system. These solutions may provide setup, engineering, and integration assistance. Using data and clever algorithms may also aid in the most effective routing of network traffic.
- Choose the right approach to traffic routing: As mentioned above, there are multiple approaches to how the traffic can be distributed across the CDN servers. Choosing the correct one for your needs will help you lower downtime and latency and provide your users a better experience.
By improving the experience for your global audience, a multi-CDN solution enhances the content provided to the users. It provides more security while lowering latency and improving availability and uptime. Using multi-CDNs has been demonstrated to be an effective way of handling the increasing traffic and latency issues experienced by websites with large traffic volumes.
If you want to learn more and see how a multi-CDN system works, you can use one of the available demos online.
