What is a content delivery network (CDN)? | IBM

CDNs provide faster load times, reduced bandwidth consumption and many other benefits for web publishers:

Better connectivity and scalability for web publishers: A content delivery network provides site users with faster content load times. For web publishers, that equates to more page views, traffic spikes, 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 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 a user requesting web content and the server delivering it can result in greater latency. Because content delivery network servers store web content caches closer to your users, they can reduce latency and improve performance.

Better response to traffic spikes: 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. Content delivery networks 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 money building out and maintaining its own geographically distributed server network.

Enhanced security: Content delivery networks employ analytics and automation tools that can uncover distributed denial of service (DDoS) attacks, man-in-the-middle attacks, firewall issues and others.

Greater user satisfaction: Slow load times and issues with media playback and application responsiveness are among the chief reasons that users abandon and/or avoid websites. Working with a content delivery network can prevent or reduce some of these performance issues, making it more likely that 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 video 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. Content delivery networks 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. Content delivery networks help B2C and B2B retailers deliver e-commerce content and apps quickly during peak traffic periods.