A Content Delivery Network, commonly known as a CDN, is an essential component of modern websites and applications. The content you see on your mobile phone—whether videos, images, audio files, or other types of media—is very likely delivered through a CDN.
In this article, Indonesian Cloud shares insights to help you understand what a CDN is and how it works.
Understanding CDN Through an Example
A Content Delivery Network is a globally distributed network of servers designed to help websites deliver content more quickly and securely.
One of the most common uses of a CDN is to improve page load times. Let’s use an e-commerce website as an example to better understand how a CDN works.
Imagine you own an e-commerce website hosted on a server located in Surabaya. All the files required by your website are stored on that server. When visitors access your website, all content is delivered directly from the Surabaya server.
Now, suppose a visitor from Palembang tries to access your website. Every website resource—such as JavaScript files, stylesheets, images, and other assets—must travel from Surabaya to Palembang, a distance of approximately 1,300 kilometers. This long distance directly affects the website’s loading speed.
How Does a CDN Improve Page Load Time?
As mentioned earlier, a CDN is a globally distributed network of servers that stores (or caches) and delivers website content. Each server in a CDN network is called a Point of Presence (PoP).
Instead of delivering website resources directly from your origin server, the CDN delivers them through the nearest PoP. So, when a visitor from Palembang accesses your website, even though your main server is in Surabaya, the content will be delivered from the CDN server closest to Palembang. This significantly reduces page load time.
Other Functions of a CDN
While improving website or application speed is the most common use case, CDNs offer several other important functions.
1. Ensuring Content Availability
This is essentially an automatic benefit of using a CDN. In simple terms, availability refers to how long your website and its features remain accessible over a certain period.
Typically, as website traffic increases, you need to add more servers to handle the load. However, unexpected issues—such as server or database failures—can cause downtime.
With a CDN:
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Most traffic is handled by CDN edge servers instead of your origin server.
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Even if your origin server encounters issues, cached content on the CDN can still be delivered to users.
2. Website Security
This advanced feature is commonly used by large enterprises. Since PoPs or edge servers are the first layer to receive incoming traffic, they also serve as the first line of defense.
If a CDN can distinguish between malicious traffic and legitimate traffic, it can block harmful requests before they reach your origin server. As a result, your server only responds to valid requests from real users.
What Types of Content Can Be Delivered via a CDN?
In theory, a CDN can cache and deliver almost all website resources. However, how long content can be cached—or whether it should be cached at all—depends on the content type.
For example, imagine your website sells Nike shoes, and two visitors are viewing the same product: one woman from Palembang and another from Makassar.
Content like product images is an ideal candidate for CDN caching. These images do not change frequently and are considered static content. JavaScript files (which control interactivity) and CSS files (which define website appearance) are also static and can be cached effectively.
However, your website may display different discounts, shipping costs, or product recommendations based on user characteristics such as gender or location. This type of content—text, pricing, APIs, or personalized recommendations—is known as dynamic content, which changes depending on the user.
Dynamic content is more challenging to cache, though not impossible. For instance, shipping costs may be cached for several hours if they don’t change frequently. However, personalized product recommendations usually change often and should not be cached.
How Is CDN Cache Updated?
One of the main functions of a CDN is caching content and delivering it efficiently to users. The longer content remains cached at a PoP, the faster your website performs. Tools like Google PageSpeed even penalize websites that fail to cache static content properly.
However, you must control how long content stays cached and how it is refreshed when updates occur. For example, if the CDN has cached an image of Nike shoes and you later update the image on your origin server, the cached version on the CDN will not automatically change.
There are established standards and best practices—such as cache-control headers and URL versioning—that ensure CDN content stays updated and synchronized with the origin server.
CDN Providers
As digital content and access devices continue to evolve, CDN providers have also become increasingly diverse. When choosing a CDN provider, consider:
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Network size and global distribution
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Strategic server locations
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Customer support availability
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Pricing
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Additional services such as security and analytics
Popular CDN providers include:
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Cloudflare
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Swiftserve
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Akamai
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Amazon CloudFront
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Incapsula
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Edgecast
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Cachefly
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Google App Engine
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CDN77
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jsDelivr
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MaxCDN
CDN Solutions from Indonesian Cloud
To support your business needs, having a high-performance website is no longer complicated. You can choose Cloudflare CDN, which acts as a proxy between your website and visitors, serving cached static content from the nearest location. With Cloudflare’s globally distributed servers, website loading speeds improve significantly.
Swiftserve CDN is another excellent option, specifically designed to deliver multimedia content quickly, securely, and reliably to users worldwide. Swiftserve leverages globally distributed PoPs through SwiftFederation, reducing network latency, offloading origin servers, and lowering content delivery costs.
We also provide VPS services through our website cloudhostingaja.com.
Indonesian Cloud is ready to help integrate these CDN solutions with your company’s website. Contact us for more information.