When Uploadcare’s customers upload their pictures to a server, they expect to be able to access them from anywhere on any device at any time without glitches or delays. The same applies to pictures you upload yourself, for example product images in your ecommerce site. A Content Delivery Network (CDN) is the best way to make sure to meet these customer expectations. But what is CDN?
Content Delivery Network is an alternative to the standard website model by which a website stores all its files on a single server — in effect, a single physical device in a specific location. How CDN works is by storing copies of the files on multiple servers around the world, sometimes known as nodes or edge servers. This speed makes a major difference to your customer base: fewer people clicking away in frustration and more people returning again and again and even paying for premium services.
By using a CDN, a site owner can make sure customers physically receive the file from a server located as geographically close to them as possible. This can not only cut the distance the file physically travels, but also the number of steps and relays it takes, both of which significantly increase the speed of delivery. That’s particularly relevant with image files: they are big enough that speed is a significant factor, but small enough that website users expect them to load without noticeable delay. We built a tool for analyzing image performance and optimizing it; this can be a good starting point in understanding how images affect page-load times.
2. Hosting Options
With the standard Web model, choosing Web hosting can be a dilemma. A site owner may want to use a main Web server in a specific part of the world for various reasons. The problem is that many of the site’s users may be located elsewhere in the world, meaning more chance of slow access speeds. With a CDN network, it’s easier to choose the main server and host that suits one’s needs.
The very nature of a CDN online means that it offers redundancy. There’s always a risk that a Web server will experience problems, either through physical damage or software glitches. With CDNs, if one node is unavailable, the network automatically reconfigures to deliver the data from the next most appropriate node to the user.
Indeed, the more images a site hosts, the more likely it is that one of them will be viewed by millions of people, even if only for a few hours. With a traditional single-server model, the surge in demand can knock a site offline. But with a CDN, the network can automatically spread the load by redirecting requests for the image across the multiple CDN servers.
The CDN setup not only means customers can load images faster, but the spreading of the load means there’s less pressure to compromise by using low-quality images. Being able to retrieve razor-sharp images almost instantaneously will impress customers and make them more likely to take up any paid service tiers you offer. Proper image manipulation can contribute significantly to speed. If you are perfecting your CDN you may also want to consider a strategy for image resizing. At Uploadcare we automatically resize user images via our CDN API.
Many computing services have two major problems as an online business grows. The first happens when the site outgrows its current setup but the business is not ready to move to the next stage up. The second is that changing a setup can be time-consuming, making it difficult to react quickly to sudden booms in business. Fortunately, the best CDN services avoid both problems: Most providers can simply “plug in” to an extra node as needed, with only an incremental cost and without any delay.
Some clients use CDN solutions to handle confidential and sensitive data, which means providers need to offer top-level cyberdefense against hacking attempts. These measures are usually applied system-wide, meaning that every customer benefits.
7. Denial of Service Attacks
There’s always a chance that one of the customer images hosted on a site will offend somebody. That creates the risk of so-called hacktivists hitting the site with a denial-of-service attack in which thousands of computers flood it with bogus requests to try to make it unavailable for legitimate users. It’s even possible that some of your less scrupulous competitors might incite similar action to try to bring you down. Such attacks can be tricky to handle with a single Web server, but the structure of a CDN is much better placed to spread the load and ride out the attack.
The Bottom Line
The worst thing in any network, be it computing or business, is a single point of failure. Using a CDN gives you added protection while retaining flexibility. It’s the online equivalent to wearing chain mail, armor and a bullet-proof vest while still being able to win a decathlon.