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3 Common CDN Myths That You Shouldn’t Believe

You just got out of the meeting with the dreaded request from management: “How do we make our website faster and more reliable?” Perhaps a customer complained or maybe the marketing team noticed visitors were abandoning the site before accessing the content. Whatever the cause, there are many reasons to improve the performance and reliability of your website.

Utilizing a content delivery network (CDN) provider is one way to do so, especially if your customers are distributed over broad geographic regions and you want to avoid deploying and managing a data center in every area.

CDNs are great tools and when applied appropriately, they can deliver impressive performance improvements. However, buying a CDN is not as simple as it sounds, nor is a CDN an automatic cure for all performance issues.  Despite the huge popularity of the CDN term, many technology professionals still believe in some common myths, often perpetuated by the largest and most popular CDN providers.

Myth 1: A CDN Solves All My Performance And Availability Concerns

A CDN is great for serving static content like images, videos, style sheets, and even javascript files, but typically CDNs don’t completely replace your web server. CDN providers generally source or copy the content from your “origin servers”, either through a special plug-in or by referencing a list of content URLs specified by you, the administrator.

While it may be possible to host your main HTML structure page in the CDN, most organizations host that key index file on their main server. Dynamic content, such as php server side scripting that generates unique content for each site visitor, usually isn’t a good fit for a CDN. If you have an application on the site that leverages a database, it’s not likely that a CDN can copy and serve that content. There are some CDN providers who offer additional caching services that attempt to offload and accelerate the content served from your main web servers, but even those services, while reducing the overall load, still leverage your main servers.

The point is that even with an amazingly optimized CDN deployment, there is a lot of content that will be still hosted on your main web server. For that main hosted content, you should at least deploy redundant servers geographically separated with failover capabilities. More sophisticated organizations will also deploy traffic management techniques to optimize the availability and performance across more than two locations for their web hosting, perhaps even utilizing a combination of physical and cloud hosted data centers.

Myth 2: One Big CDN Provider Is All I Need For My Global Presence

Large CDN providers boast about their huge global networks and assert that they are the only provider you will ever need. It’s true that some do have large global networks, but just because they have a presence doesn’t mean that they’re the best option for you in every geographic area for all content, all the time.

Different CDN vendors may utilize different network providers, peering partners, or hosting locations. In some regions, one CDN provider may perform better than another or have a better video optimizing service. Having the ability to prefer different CDNs for different locations can dramatically improve your site’s performance in specific regions.

What happens when that large CDN has a major problem? If you are already set up to leverage more than one CDN, your site will not only remain operational, but you can distribute traffic to your other CDN providers and still maintain many of the performance benefits. It’s a good practice to employ redundancy and high availability for every aspect of your site, including your CDN.

Our friends at Turbobytes understand the benefit of deploying with multiple CDNs and have created their service to help organizations determine the best endpoints to use for their website and manage multiple CDNs seamlessly.

Turbobytes Quote“Our customers demand excellent performance everywhere all the time. No single CDN provider can provide that. They all have hiccups and parts of the world where they are not great” said Aaron Peters, CEO of Turbobytes. “A multi-CDN strategy is essential when building a high-performance global presence. It may require up to five CDN vendors to get the best availability and speed in all markets.”

If you’re interested in digging deeper, check out Getting a Grip on CDN Performance – Why & How, a document / presentation that I found created by Turbobytes.

Properly utilizing multiple CDNs can save money in addition to improving worldwide performance. Using multiple providers gives a company leverage in negotiations and provides the ability to target specific geographic areas and services, allowin them to purchase only what they need from each CDN provider.

Myth 3: The Free Or Really Cheap DNS From My CDN Is All I Need…Bundling Is Good

While it may seem convenient and cost effective to use the DNS offered by your CDN provider, you are likely paying the price in unexpected areas. Large CDN providers may try to lock you into only using their services by making it difficult to load balance to multiple endpoints outside of their network. This takes away the flexibility that you would have with multiple providers and makes it difficult to scale, add another CDN, or adapt to fluid business requirements.

It also prevents or makes it difficult to provide failover and traffic management services for all the other content not served by the CDN such as the origin servers and dynamic content.

If your DNS is running on the same network as your CDN and if there is a problem, not only does your CDN go down, but your DNS does too, making it impossible to access your website, adapt, or leverage other solutions. A great example of this: in 2011, major websites like Facebook and BestBuy.com experienced downtime when their CDN, Akamai, faced DNS issues.

Be wary of the CDN provider that confusingly implies that their DNS services are hosted on their same vast worldwide CDN network. Their DNS network often consists of a small subset of the overall network and since DNS is not their primary business, it often doesn’t receive the attention and focus you would experience from a company that builds its reputation on providing professional DNS services.


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Whois: Nate Meyer

Nate Meyer is the Director of Traffic Management Products for Dyn, the world leader in Internet Performance Solutions that delivers traffic management, message management, and performance assurance. Follow Dyn on Twitter at @Dyn.