CDN

Definition

CDN stands for Content Delivery Network. It is a system of distributed servers that deliver web content, media, and applications to users based on their geographic location. By caching content across multiple nodes worldwide, a CDN reduces the distance between the user and the server, improving speed and reliability.

CDNs are commonly used for websites, streaming platforms, e-commerce stores, and SaaS applications that require high availability and low latency. They help businesses provide consistent performance to global audiences.

Advanced

At an advanced level, CDNs use edge servers to cache static assets such as images, videos, scripts, and stylesheets. They also support dynamic content acceleration, load balancing, and DDoS protection. Some providers integrate with DNS routing and real-time analytics to optimise traffic flow.

Advanced CDNs offer features like TLS encryption, smart caching strategies, and API-driven content invalidation. Providers such as Cloudflare, Akamai, and AWS CloudFront serve billions of requests daily with built-in redundancy and failover systems.

Why it matters

• Reduces latency by serving content closer to users.
• Improves website and application load times.
• Enhances security with DDoS mitigation and encryption.
• Supports scalability during traffic spikes or global events.

Use cases

• Accelerating e-commerce platforms during peak sales.
• Delivering high-quality video and live streams.
• Powering SaaS tools with global performance needs.
• Securing websites against cyberattacks.

Metrics

• Latency and response times from edge servers.
• Cache hit ratio versus origin server requests.
• Bandwidth usage and throughput improvements.
• Availability and uptime across regions.

Issues

• Misconfigured caching can serve outdated content.
• Extra cost for advanced CDN features and global coverage.
• Reliance on a third-party provider introduces vendor dependency.
• Not all dynamic content benefits equally from CDN delivery.

Example

A news website implements a CDN to handle global traffic spikes during breaking events. Content is cached on servers worldwide, reducing load on the origin server and delivering pages to users quickly, improving engagement.