What is a Content Delivery Network? (CDN)

A Content Delivery Network (CDN), also known as Content Distribution Network, is a system of interconnected servers based in different locations. Its role is to facilitate more efficient content delivery: it presents users with cached online content from the nearest network server instead of fresh content.

By decreasing the amount of time required for users to receive rich media and content, a CDN can significantly enhance web performance. The majority of web traffic is served by CDNs today, including giants like Netflix and Facebook.

Why do so many website owners use a CDN?

Website owners and brands use Content Delivery Networks to transfer content in a faster, simpler way. They can rely on a CDN to deliver website files, videos, and images to countless users all over the world. Crucially, a content delivery network can enhance web page load times and decrease strain on the primary server. As a result, they can provide visitors with a stronger experience, particularly those based a long way from the server of origin.

A CDN may also boost a website’s security and reliability, delivering content from multiple servers. That makes websites less vulnerable to cyber-attacks and potentially costly downtime.

How do content delivery networks operate?

Retrieving cached content from a CDN network edge happens out of view of the users, leaving many people unaware of the process. The software that manages content delivery networks determines which server is based closest to the user, it initiates the request and then delivers the content as required.

To deliver cached content to the user, along with fresh content that has yet to be cached, CDN edge servers and the server of origin need to communicate. Edge servers cut the number of miles that content has to travel and the amount of hops data packets are required to make to reach users. That leads to quicker performance and improved bandwidth. Latency and timeouts are less likely, creating a stronger user experience overall.

If an internet outage or cyber attack strikes, new content that is cached and hosted on a content delivery network server is still available to users closest to the edge locations until the CND server’s timetolive expires. If a website server experiences technical issues, the site itself remains accessible if it was successfully cached on servers distributed across different locations.

To deliver content to users from the closest server location, companies invest in services from CDN providers. Those CDN providers may host content themselves, or they will work with internet service providers and network operators to host the servers instead.

Additionally, CDN providers leverage solidstate drives (SSDs) and load balancing to deliver data in less time. They use algorithms and compression to reduce the size of files. To keep load times and transmission times brief, they also utilize artificial intelligence and machine learning.

What does CDN caching involve?

A CDN’s functionality largely depends on static content being cached, with CDN edge servers storing and caching the data. Here’s an example of the standard caching process:

A Bostonbased web server hosts static content. A user in Los Angeles requests that content.
The origin server in Boston gets the request, and then delivers a response to the user. At the same time, it sends a copy of that response to the user’s nearest CDN pointofpresence (POP).
The file copy is stored and cached by the CDN POP.
If that user or a different one completes a similar request, the response is delivered by the server holding the cached version instead of the origin server.

What’s the difference between a CDN and a web host?

Content delivery networks and web hosts may use similar technology, but they have different purposes. Here are the major differences between CDNs and web hosts: CDNs don’t deliver content the last mile to users, unlike web hosts, and offer temporary caching and storage only.

Web hosts are responsible for hosting sites, whereas CDNs cache content at the network edge to boost performance rather than hosting it. The majority of sites that experience performance difficulties will use a CDN to deliver a better experience.

With web hosting, providers offer access to one server that deals with delivery requests, hostname resolution, and more. CNDs, though, rely on connected servers distributed worldwide, which cuts website response times by serving data from the nearest edge site to the user.

Conventional web hosting can involve various problems, such as security threats, limited bandwidth, and service outages. However, CDNs use content caching on edge servers to get around these issues.

While web hosts serve every form of content, only static data is served and hosted by CDNs. That reduces CDNs’ workloads and enables them to focus on edge delivery.

What are the main functions of a CDN?

A Content Delivery Network’s primary purpose is delivering content via a group of connected servers as efficiently and securely as possible. CDNs offer improved performance, availability, and security. Furthermore, companies may use CDNs for gathering user analytics and traffic data.

The variety of content served by CDNs encompasses mobile apps, websites, downloadable items, and media streaming (e.g. films). CDNs may also be used by search engines and social media platforms.

Companies that own content often rely on CDNs to deliver dynamic and static content in a more efficient way, as well as mobile content, online games, and a range of other services. Common CDN use cases include:
A financial institution transfers sensitive data safely with a CDN.

A company providing mobile apps cuts load times and improves response times with a CDN. That delivers a stronger user experience overall.

An online store relies on a CDN for delivering content during periods of heavy traffic.

What benefits does a CDN offer?

A CDN offers the following benefits:

Improved security

Content delivery network providers don’t just offer content caching and delivery their services also incorporate cuttingedge security measures. CDN providers can protect networks by mitigating bot attacks and distributeddenialofservice (DDoS) attacks, and implementing firewalls for web apps.

Enhanced efficiency

As CDNs can enhance load times for web pages and cut bounce rates, they can deliver more efficient performance. That will reduce the risk of users leaving a site because it’s too slow.

Highquality optimization

CDNs can provide a wide range of optimization services alongside caching content, capable of optimizing content and performance.

Better availability

CDNs can provide website owners with scalability, as sites are distributed throughout numerous servers miles apart. These can accommodate greater traffic volumes and reduce the risk of network failures more effectively than origin servers can. That makes content more convenient to access than ever.

Save money and resources

You can expect to use less bandwidth and spend less money with CDNs.

Highquality caching

CDN providers use thirdparty data centers or their own POPs to store cached content. Whenever users request content from a site which is cached on a CDN, the request is channeled to the user’s closest server. The cached content is then delivered from its network edge location. The user is unaware of this complex and crucial process.

Decreased latency

As traffic is carried across great distances and multiple networks, CDN architecture cuts network latency in a big way. Reducing latency is critical when delivering dynamic content, software, and media to mobile devices all over the world. A trusted provider can help companies deliver content with very low latency.

Higher performance

For countless businesses, caching content with CDNs is vital for achieving their performance requirements. CDN providers are in greater demand as more websites feature video streaming, stores, and cloudbased applications, all of which require solid performance.
A limited number of CDNs have set up POPs in each country worldwide, and businesses need to rely on multiple CDN providers to deliver their content as expected.

Diversified services

CDNs offer various services, such as performance and acceleration solutions for websites and applications. They also provide optimization for media, application programming interfaces, and more.

Popular CDN platforms

You can choose from a wide range of CDN platforms, and each boasts various features. Popular options include:
Amazon CloudFront

Certain providers are promoted as CDNs with extra services (e.g. DDoS), while others include CDN solutions as part of their wider cloud services (e.g. security).

When did CDNs first appear?

Content delivery networks are a critical component of today’s online infrastructure, created to make website performance more efficient for users across the globe. CDNs have advanced significantly in the decades since the first debuted, and there have been three generations of CDNs in total.


The original static CDN was released by Akami in 1998, and that company’s work remains the foundation of the latest CDNs. These first CDNs primarily handled static content, including video streaming and software downloads.
The key features of these were:
Enhanced server performance
High price tags
A focus on corporate users
Utilized origin push caching
Suitable for HTML and downloadable content
Had a dispersed network topology


The next generation of CDN services changed to suit the increase in mobile and cloud computing. They allowed for efficient delivery of complex content and multimedia. As more people started using the internet daily, more CDN providers launched too, with a wider range of services available.
Key features of dynamic CDNs include:
Utilized origin pull caching

Made servers and resources more efficient and accessible
High costs
Delivered dynamic content, static content, and rich media
Had a consolidated network topology


The next evolution of CDNs involves numerous CDNs from different providers, with a huge POP network (instead of only one). That helps deliver content to users faster, serving in more locations with better cybersecurity protection. Key features of multipurpose CDNs include:
Utilize origin pull caching
Better performance and security
More costeffective pricing
Delivers static content, dynamic content, and rich media
Leverages a highly consolidated topology

Multipurpose CDNs are suitable for all website owners, across industries and locations.
If you’re curious about trying CDN services, one of the most important factors to consider is the cost. Pricing models differ from one CDN provider to another. In some cases, they revolve around usage or the amount of content delivered. In others, though, providers have a flat fee for their services, though they may even offer them for free. There could be extra charges for optimization and performance, though, so research your options carefully.

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