Content delivery network (CDN) is a network of geographically dispersed servers that enables faster web performance by locating copies of web content closer to end users or facilitating delivery of dynamic content (e.g., live video feeds).
Each CDN server is located on what is called the network edge—closer to end users than the host server, which is where the web site originates. For this reason, CDN servers are often called edge servers. Each CDN server stores or caches copies of a subset of the web content—HTML files, images, audio, video, applications—from the host server. By reducing the distance between this content and end users, the CDN helps the website publisher provide faster performance for its users and control its own bandwidth consumption and costs.Organizations typically purchase CDN services from CDN providers, which maintain their own server network.
Benefits of a CDN
- Better results for web publishers: A CDN provides site users with faster content load times. For web publishers, that equates to more page views, improved customer engagement, and less site abandonment.
- Reduced bandwidth consumption: Web hosts charge organizations for data transferred from the origin server. By storing copies of content closer to the end users, a CDN enables fewer data transfers from the origin server, reducing an organization’s bandwidth consumption and costs.
- Reduced latency: Latency refers to the delay between the time data is requested from a system and when the system actually starts sending it in response. A greater distance between an end user requesting web content and the server delivering can result in greater latency. Because CDN servers store web content caches closer to your users, they can reduce latency and improve performance.
- Better response to spikes or surges in traffic: A successful marketing campaign, a limited-time offer, a video gone viral—these types of events can create a sudden (anticipated or unanticipated) increase in content demand. CDNs use load balancing to distribute this demand across servers to prevent overloading any single server. Load balancing also helps keep the spike or surge in demand from impacting website performance.
- Outsourced infrastructure support: By relying on a CDN, an organization does not have to spend time, human capital, or expenses building out and maintaining its own geographically distributed server network.
- Enhanced security: CDNs employ analytics and automation tools that can uncover distributed denial of service (DDoS) attacks, man-in-the-middle attacks, and other common attacks on websites.
- Greater user satisfaction: Slow load times, media playback, and application responsiveness are among the chief reasons that users abandon and/or avoid web sites. Working with a CDN can prevent or reduce some of these performance issues, making it more likely content consumers will be satisfied with their site interactions.
- Improved content delivery: Not only do CDNs deliver content faster, but they also improve the quality of the delivered content. Video replay, video calls, and live streaming can be hindered by slow transmission, which may result in jitter. Buffering, poor image and sound quality, and incomplete transmissions also affect the delivery of video and audio content. CDNs help by shortening the distance between the content and the user and by load balancing traffic to prevent overwhelming routers or servers.
- Speedier e-commerce: E-commerce consumers have high expectations for online shopping experiences—they expect fast product image load times, quick payment method approvals, and easy transactions on any mobile or desktop device. CDNs help B2C and B2B retailers deliver e-commerce content and apps quickly during peak traffic periods.