A CDN speeds up content delivery.
A decent network with a large number of points of presence helps increase the speed of a website or app and reduces delays in video broadcasts. But sometimes one CDN may not be enough to solve every problem your business faces, and you have to use several.
A Multi-CDN is a combination of different CDNs. This solution helps to achieve better performance and fault tolerance. But more resources also cost more. Therefore, a Multi-CDN is not suitable in every case.
Let’s figure out in which cases the use of several content delivery networks will be optimal, and how to properly distribute the load among them.
If you use a CDN from one provider, you depend entirely on the reliability of their network. If there is a major failure, your resources will be unavailable.
If you use multiple CDNs, you can redistribute the load to other networks in the event of a disaster, so that your users won’t notice anything at all.
If it’s critical for you that your resources remain available at all times, a Multi-CDN is the right solution.
For a CDN to work at maximum efficiency, its points of presence need to be located as close to the end users as possible. It’s best to find a provider whose cache servers are located in the same regions that you serve. Then, one network will do the job perfectly.
But this is not always the case. Let’s say some of your clients live in Canada. There is a provider that provides excellent coverage in that country. But they have very few points of presence in the US, where many of your users also live.
In this case, the best solution would be to find another company with good coverage in the US and connect both networks. Canadian traffic will go through one CDN, and US traffic through another.
If you use several CDNs, you have more points of presence, more routes, and better bandwidth, which means that the content delivery speed is much higher. This is especially useful when there are large bursts of traffic and one network cannot handle the load.
Different CDNs also have different features. Some providers are better at delivering “heavy” images and videos, while others are ideal for dynamic content.
If you haven’t found a provider that meets all your requirements 100%, a use Multi-CDN. This way, you can deliver different types of content across different networks, thereby combining their benefits and speeding up your resources.
Providers may have different prices for content delivery in different regions. Imagine you’re choosing between two companies that suit you equally well. But one offers a good CDN price in America and a very high price in Europe, while the other offers the opposite.
In order not to have to choose the lesser of two evils, connect both CDNs, but redirect traffic so that in each region it goes over a cheaper network. This saves you money.
How you distribute the load depends on what you are using the Multi-CDN for.
To see if you have distributed the load correctly, check how the network is performing.
Take a look at the statistics. Be sure to ask the providers for raw logs, which can be used to analyze the CDN’s performance.
To analyze the performance correctly, it’s desirable that the monitoring parameters be as consistent as possible with each other: providers compose reports for the same periods of time, the data sets about the CDN operation are equally complete, and the statistical parameters are the same.
You may not be able to fully align the monitoring strategies for each network. Each provider has its own statistics and its own logic by which it’s provided. For example, one company may provide a report on the amount of traffic from different countries, while another doesn’t offer that option.
However, agreeing on some parameters and bringing reports from different providers into accordance is in your power.
A huge number of requests come from several CDNs to one server. There can be so many of them that the origin simply can’t cope.
Shielding will help you avoid this situation. It provides additional protection against overloading the origin.
All requests from a CDN first go to a special pre-cache server, and from there to the origin. Thus, only one server communicates with the origin, not the entire network. The number of connections is reduced this way, which means less load and higher productivity.
You can distribute the load between different CDNs using our DNS hosting. It allows our customers to redirect requests based on user location or on a set percentage.
Repeat these steps for each region, requests from which should be directed to different CDNs.
However, you don’t have to create CNAME records for each region separately. For example, if you’re using two CDNs, and you want traffic from Australia to go over one network and the rest over another, you only need to create two CNAME records: one for traffic from Australia, and one for the rest of it.
To create a record for all other regions, in the Name field, specify the balanced subdomain without a region, and in the Record Content field specify the zone where requests will be sent.
Repeat these steps for each CDN.
Read more about configuring DNS balancing in our Knowledge Base.
Connect our DNS hosting for free to easily manage your Multi-CDN.
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