Content Delivery Network

What is Content Delivery Network (CDN)?

A Content Delivery Network (CDN) is a distributed system of servers strategically placed across various locations to deliver web content—such as images, videos, scripts, or entire web pages—faster and more reliably to users based on their geographic location.

Why is CDN useful?

CDNs are useful because they: - Reduce latency by serving content closer to the user - Improve website loading speed and user experience - Offload traffic from origin servers - Provide redundancy and availability - Enhance security with DDoS protection and WAF integration

How it works?

A CDN works by: - Caching content on edge servers in multiple geographic locations - When a user requests content, the CDN directs the request to the nearest edge server - If the content is cached, it is served immediately; otherwise, it’s fetched from the origin server and cached for future use - DNS-based load balancing and routing mechanisms are used to determine optimal paths

Where is CDN used?

CDNs are used in: - Websites and web applications - Video streaming platforms - E-commerce platforms - Software distribution (e.g., OS updates, app downloads) - Media and news portals - Popular CDNs include Cloudflare, Akamai, Amazon CloudFront, Fastly, and Google Cloud CDN.

Which OSI layer does this protocol belong to?

CDNs operate mainly at the Application Layer (Layer 7), though they also involve Layer 4 (Transport) and Layer 3 (Network) for routing and delivery optimization.

Is CDN Windows specific?

No, CDNs are not Windows specific. They are platform-independent and serve content to any device or OS that can make web requests.

Is CDN Linux specific?

No, CDNs are not Linux specific. While many CDN edge servers may run on Linux, CDNs are accessible from all operating systems and platforms.

Which Transport Protocol is used by CDN?

CDNs use: - HTTP and HTTPS (primary) - TCP and increasingly QUIC (over UDP) - Some also support WebSockets, RTMP, and HLS for streaming

Which Port is used by CDN?

Common ports include: - Port 80 for HTTP - Port 443 for HTTPS Additional ports may be used depending on custom configurations (e.g., streaming protocols).

Is CDN using Client server model?

Yes, CDNs follow the client-server model. - Clients (browsers or apps) send requests. - CDN edge servers act as intermediaries that respond to those requests, serving cached content or proxying to the origin server if needed.

Topics in this section,

  • In this section, you are going to learn

  • Terminology

  • Version Info

  • rfc details

  • setup

  • setup

  • packet details

  • usecases

  • features

  • Reference links