Cdn
How CDNs work — edge caching, static asset delivery, cache invalidation, and when to use a CDN vs origin storage.
Stores images Stores html Stores videos
A CDN is a network of servers placed in different locations that stores or delivers content closer to users.
Serve images serve html serve videos serve some API - cached
origin Server
How Data will reach to these Edge Servers
Pull-Based Approach
Push Based Approach
edge server will get the latest data
Problem: - if something changed in origin server it will take some time again
1. TTL - time to live image.png TTL = 1hr 2. Cache Invalidation / Purge -> we delete the image from edge server when we change something in origin server 3. Cache Revalidation : image.png ttl : 1 hr , cr : 30 4. Change Image ID / URL
Multi Layer CDN
Example tools/providers
AWS CloudFront
Companies Highly relying on CDN