-->

Understanding A Multi-CDN Strategy

Article Featured Image

Many enterprises are finding it increasingly difficult to deliver a consistently high-quality end user experience to a global online audience using a single content delivery network (CDN). CDN providers have different strengths and weaknesses—unsurprisingly, a single provider does not adequately address the needs of a global online organization. However, businesses can use a multi-CDN strategy, and by leveraging the right combination of providers, enterprises can simultaneously improve end user quality of experience while lowering costs.

A content delivery network (CDN) is a group of geographically distributed servers that help deliver content to users more rapidly. However, CDNs can perform differently at different times or in different locations and they can experience outages and slowdowns. With a multi-CDN strategy, your organization’s content is hosted with more than one CDN provider, enabling you to drive better application performance; and in many cases, you can enjoy lower costs. Multi-channel access methods for websites are not the only things a content owner must consider; demographics and the purpose of the site also come into play. Many enterprises are finding it increasingly difficult to deliver a consistently high-quality end user experience to a global online audience using a single CDN. Unsurprisingly, a single provider does not adequately address the needs of a global online organization. However, businesses can use a multi-CDN and by leveraging the right combination of providers, enterprises can simultaneously improve end user quality of experience while lowering costs.

The majority of shoppers state that they will leave a page if it takes more than three seconds to load, and potentially every second in delay in load time can mean fewer page loads and fewer conversions—the bigger your ecommerce property, the greater the damage. For the largest properties, this can mean millions of dollars in lost revenue. The performance of a single CDN often varies by geography, performing well in some regions and not so well in others. This is a function of regional coverage and connectivity of the CDN points of presence (PoPs). Even the best-performing CDNs regularly experience spikes in latency that can last for hours. Global online organizations need their applications to perform well in all regions and at all times. A multi-CDN strategy, including adding regional CDNs where global CDNs' performance is consistently slower, can deliver better performance than one CDN for all.

Multi-CDNs are used by a variety of industries such as internet/computer software, media, retail, leisure, sports & recreation, and corporate services. These industries deliver vast amounts of content to users across the globe, and using a multi-CDN can help improve the efficiency of that process. It is no surprise that Internet / Computer Software and Media companies are among the top two industries using single and multi CDNs. Companies that stream large media files to their users are able to take great advantage of the widespread global presence of a multi-CDN setup. Additionally, software companies like to push their most recent updates to users via a CDN as they will be delivered faster. 

To give your site the ability to allow multiple CDNs to cache your content, you must first understand your current delivery ecosystem. The business logic that may live on parts of the CDN has to be pulled back and implemented at the origin. If your CDN does not allow its storage to be used as third-party origin storage, then best practice would be to have multiple origins (at least a primary and a failover). Multiple geo-located origins may be good for larger sites or mobile apps with high data needs (online gaming for example). Also, limit the number of features that you utilize with a specific CDN—put the intelligence in your origin, where possible, as that’s your value proposition. Attempt to use CDNs only for delivery, because by pulling the business logic back into the origin and performing these tasks yourself, you have set the scene for multiple CDN delivery. Limit the use of CDN origin storage, as this will have to be replicated across multiple CDNs if you use it. Instead, opt for using cloud storage in multiple locations or set up your storage to be near your own origin(s).

Do you properly understand your traffic? For example, is it HTTP or HTTPS? Is it large file format or video? The type of traffic you have largely determines your caching capabilities. Also, large file delivery is usually improved dramatically by increased throughput. So if that’s your use case, then optimize for that by selecting CDNs that have great throughput in the markets you care about. Likewise, if HTTPS small object is the majority of what you want optimized, then tune your networks accordingly. 

Focus on the important key performance indicators (KPIs) for your business. When considering business requirements, think granularly. Remember that in different countries, you will have different constraints and opportunities. You might even have different requirements, depending on the type of media or time of day. Investigate what your users are actually experiencing, as you need to know the range of your performance for every audience, in every context.

Measure the right thing. If you are using only a server-side experience measurement today, then look at actual user performance results as well. Server-side metrics can tell you about load and latency on the servers, but they offer little insight into the actual customer experience. In order to make the best decisions about content delivery partners and platforms, you need true visibility into your customers’ experiences, globally. Real user measurements (RUM) and high quality synthetic measurements can take the guesswork out of how your site is performing in different locations across different networks.

[This is a contributed byline from GlobalDots. We accept vendor bylines based solely on their value to our readers.]

Streaming Covers
Free
for qualified subscribers
Subscribe Now Current Issue Past Issues
Related Articles

The Algorithm Series: The Math Behind the CDN

Delivering content at scale requires a number of precise, discrete, yet interconnected steps, starting with an acute awareness of server loads.

CDN Scaling Strategies

Limelight Networks' Neil Glazebrook and Tulix CEO George Bokuchava discuss cost-effective strategies for building capacity in this clip from their panel at Streaming Media West 2019.