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    Definitions 4 min read

    A content delivery network (CDN) is a system of geographically distributed servers that work together to provide fast delivery of internet content, serving over half of all internet traffic. It’s designed to minimize latency in loading web pages by reducing the physical distance between the server and the user.

    A CDN allows for a quick transfer of assets needed to load content, whether static content or dynamic content such as HTML pages, javascript files, stylesheets, images, and video streaming. A well-configured CDN can also help protect against common malicious attacks such as distributed denial-of-service (DDoS) attacks.

    How does a Content Delivery Network (CDN) Work?

    To minimize distance between visitors and the website’s server, CDN edge servers store a cached version of its content in multiple geographic locations known as the points of presence (PoP).

    Caching is the process of storing a copy of a resource like a file in a cache, or temporary storage location (CDN edge server or multiple servers), and serving the cached content back when requested. Each PoP contains caching servers designed to deliver web content to visitors within its proximity. 

    For example, visitors in the United States wishing to view content that originates from a U.K.-based server will have to deal with slow loading times if user requests have to travel across the Atlantic Ocean. To eliminate the latency, a CDN will store the content in a local United States PoP.

    The process of using a CDN is nearly invisible to the user. The only way a user would know if a CDN has been accessed is if the delivered URL is different from the URL that has been requested.

    Fastly vs. Cloudflare: Compare two top CDNs

    Benefits of a Content Delivery Network (CDN)

    The benefits of using a CDN will depend on the needs and size of an internet property, which includes all URLs; internal protocol addresses; and corresponding domain names, like registrations and applications. However, the main benefits users can take advantage of include:

    Faster Website Load Times (Latency Reduction)

    Using a nearby CDN server can distribute website content closer to website visitors, which will have them experience faster page loading times. Therefore, CDN servers can reduce bounce rates by removing the obstacle of slow loading site pages. A CDN service can reduce load times in the following ways:

    • Instead of connecting to the location of a website’s origin server (traditional CDN), a content delivery network allows users to connect to a data center that is geographically closer. The less distance spent traveling means the less time spent loading, plus it reduces load on the original server.
    • Hardware and software enhancements such as load balancing and solid state drives help data reach the user faster.
    • A CDN will reduce the amount of data transferred by reducing file sizes with processes such as minification or file compression.
    • Sites using TLS or SSL certificates can be sped up by CDNs by optimizing connection reuse and enabling TLS false start.

    Reduced Bandwidth Costs

    Bandwidth consumption is one of the main expenses for a website. Through caching for example, CDNs are able to reduce the amount of data an origin server would need to provide. This ultimately reduces the hosting cost for website owners.

    Increase in Content Availability and Redundancy

    A large amount of traffic or a hardware failure can prevent a website from functioning normally. Through the distributed nature of CDN server, any CDN architecture should be able to handle more traffic and better withstand hardware failure than an origin server.

    Improved Website Security

    A CDN server can improve security against DDoS attacks by offering DDoS mitigation and improvements to security certificates. This is because they are built to analyze and absorb unusual traffic spikes. These spikes can be pinpointed and identified as malicious IP addresses that are on a deny or blacklist.

    Multiple CDNs will also include a web application firewall (WAF) to provide extra protection for your website. A web application firewall helps protect content owners by filtering, monitoring, and blocking malicious HTTP/S traffic that travels to a web application. It is able to do this by adhering to preset policies that determine what traffic is malicious or safe.

    CDN Providers

    If you run your own website, using a CDN provider can boost the performance of your website and user experiences. Below is a list of popular CDN providers.