What is Multi CDN and why businesses are adopting it

To understand what is Multi CDN, we need to take one step back and look at ‘Content Delivery Networks‘ (CDNs). CDN has become commonplace in the world of website management for several key reasons. Website owners have come to rely on the increased loading speed and added security that comes with using a geographically distributed group of servers. CDNs also enhance streaming capabilities and can help high-profile sites manage large amounts of daily traffic.

CDNs have some limitations, however. While load times are improved when users access websites served from a nearby CDN, those benefits do not extend to websites loaded from farther away. In an increasingly globally-connected and internationally-competitive world, a typical CDN structure can limit an organizations’ reach, and ultimately, its success.

Many companies are turning to Multi CDN technology to mitigate these global access issues.

What is Multi CDN?

A Multi CDN, as the name implies, is a method that uses multiple CDNs from different providers simultaneously to achieve better website performance. This is an improvement over the typical method, where organizations subscribe to multiple CDNs based on performance requirements in order to achieve similar performance enhancements.

While Multi CDN strategy isn’t a new concept, there hasn’t been a true off-the-shelf Multi CDN solution before the launch of mlytics platform.

Traditionally setting up Multi CDN requires businesses to activate and manage each CDN individually. A proper load balancing method that can fully utilize the activated CDNs also needs to be planned to effectively utilize the CDNs.

Why Multi CDN?

Growing organizations stand to gain several key benefits from investing in Multi CDN technology. Using a Multi CDN setup can solve issues or help a company expand into a new market. Multi CDNs offer several attractive benefits:

1. Global performance enhancement is one potential benefit. Single CDN performance can vary by region, but Multi CDNs spread across several regions improves overall latency stats. Regions like China and Russia present notorious challenges to website delivery, for example, and a Multi CDN strategy can help organizations work around issues related to local regulations and controls. Multi CDN allows companies to gain granular control of their content delivery, sometimes all the way down to the city level.
2. Uninterrupted, continuous website uptime is possible with Multi CDN. When one CDN provider experiences an outage, Multi CDN an route web traffic through another provider. Web content delivered by Multi CDNs is not affected by traffic spikes or fluctuations.
3. User expectations around streaming media can present hurdles for up-and-coming organizations. Modern websites must be able to not only deliver graphic-heavy content, but users expect that content to be of high quality and delivered near-instantly. This can be an impossible issue to overcome with single CDN setups. Multi CDNs can help ensure that websites can keep up with users’ demands.
4. Using a Multi CDN provider can improve website load times by distributing content through nearby CDN servers. Faster load times can reduce bounce rates and increase the amount of time visitors spend on a website.
5. Organizations can save on bandwidth costs and overage fees by using a Multi CDN.
6. Multi CDNs can enhance security by providing features like DDoS mitigation and authentication enhancements.
7. Flexibility is a very important factor to reduce risks for both financial and technical reasons. Instead of being locked into a single CDN provider, businesses often have more flexibility when using Multi CDN to spread risks across the board.

Multi CDN in the age of cloud incidents

Most likely, you’ve selected a CDN that promises reliable service. In truth, even the largest, most trusted service providers can experience unexpected downtime, sometimes with devastating consequences. Lost profits due to website downtime are bad enough; the long term, negative impact of tainted customer loyalty could be even worse.

You won’t even be able to complete a meme properly if there’s an outage

There’s a good chance you’ve personally been affected by a CDN outage at some point. CDN downtime has affected popular, heavily-trafficked websites like Amazon, Netflix, Facebook, and Verizon, to name just a few. If companies as prominent as these can be taken out by CDN failure, it’s easy to understand why smaller organizations are equally, if not, more vulnerable when they rely on a single CDN provider.

Most companies cannot easily absorb this kind of financial hit. Maximizing website availability is a must for any company hoping to expand or maintain market share. Websites related to financial transactions, e-commerce, and multimedia are especially vulnerable to the consequences of website downtime.

Okay, I’m convinced — what’s the best way to implement Multi CDN?

Method #1 — DNS load balancing

There are a couple of DNS providers on the market that allow users to customize their traffic routing rules. Once they have subscribed to all the CDNs they need, they can copy the CNAMEs of all the CDNs and paste it in the DNS record so the DNS server can determine which CNAME (CDN) to use for the request based on the traffic routing rules. Here are some of the most common traffic routing rules:

• Round robin — CDNs “take turns” serving content to spread the load across activated CDNs. This method doesn’t take any factors into account, simply distributing traffic to all CDNs equally.
• Weighted round-robin — Also known as “ratio load balancing”, instead of equally distributing traffic across all CDNs, this method sets traffic ratio to weight traffic accordingly and assign priorities to specific CDNs.
• Geolocation — This method determines a user’s location and finds the closest PoP/CDN to distribute their requests (traffic).

How it works

1. When a user visits www.test.com, this triggers a DNS lookup.
2. The DNS provider will determine which CNAME to use based on the traffic routing rules.
3. The request is now being directed to the designated CDN based on the CNAME.
4. The user is now accessing www.test.com via the assigned CDN.

Pros

• The easiest option for most businesses

Cons

• Need to subscribe to CDNs individually via different platforms (more platform and contract to manage)
• Most DNS do not perform load balancing intelligently

Method #2 — RUM/synthetic monitoring-driven load balancing

Some providers including mlytics offer this service as a package to push Multi CDN to the next level. The basic idea is to utilize the RUM and synthetic monitoring data as the foundation to drive load balancing decisions.

DNS providers that offer this service usually process this on the DNS level, meaning it’s pretty much similar to the ‘DNS load balancing’ method, except it’s making decisions intelligently based on actual performance data. Other providers including mlytics process this on the system level taking in requests, measure, and return the best CNAME or IP (of a CDN) back to the DNS.

How it works

1. When a user visits www.test.com, this triggers a DNS lookup.
2. The system will measure user geolocation, network latency, and CDN performance.
3. The system finds out the best CDN for the user, and route the request to the designated CDN.
4. The user is now accessing www.test.com via the assigned CDN.

Pros

• Ensures the best experience for users
• Zero programmings required, everything’s off-the-shelf

Cons

• Need to subscribe to CDNs individually via different platforms (more platform and contract to manage)

Method #3 — Turnkey Multi CDN platform

This is pretty much method 2 (RUM/synthetic monitoring-driven load balancing) plus eliminating the hassle of the CDN subscription process. There are several providers in this field, but only mlytics provides a marketplace-like experience, which gives businesses the power to subscribe to any CDNs on demand instead of asking the providers to do so on behalf.

How it works

1. When a user visits www.test.com, this triggers a DNS lookup.
2. The request is redirected to the mlytics system via the CNAME assigned by mlytics if it is properly pasted in the DNS record.
3. The system will measure user geolocation, network latency, and CDN performance.
4. The system finds out the best CDN for the user, and route the request to the designated CDN.
5. The user is now accessing www.test.com via the assigned CDN.

Pros

• One platform to rule them all: subscribe to and manage multiple CDNs via one single platform
• Unified configuration and analytics for multiple CDNs

Cons

• Some lesser-known CDNs might not be immediately available

Our approach

When we started this project, we went back to the drawing board and ask: “what’s the most painful part of the process?”. It all boils down to the lack of connection between CDN activation and load balancing implementation.

Unlike some providers on the market which mostly tackle Multi CDN via DNS, we wanted to build a turnkey solution in which users can easily take care of CDN implementation and load balancing configuration all in one place. We truly believe this is the best experience to use, manage, and maximize the value of a Multi CDN model.

We’ve been since working closely with major CDN providers around the world including Alibaba Cloud, Akamai, AWS, Cloudflare, and more. We’ve integrated those CDNs onto a platform, and designed a marketplace-like interface which allows businesses to subscribe to CDNs with just a few clicks without having to negotiate and lock into a long-term contract.

We also developed a system that can intelligently route traffic across all the CDNs activated via the platform which takes the end-user geolocation and CDN performance status into consideration when making routing decisions.

Learn more about mlytics.