Copies closer to visitors
A content delivery network (CDN) keeps copies of a website’s images, videos, and other files on servers in different regions. Your browser can get a nearby copy instead of fetching everything from the website’s own server.
This can make pages load faster and reduce work for the website’s server when many people visit at once. Cloudflare is one company that offers a CDN.
Keeping copies fresh
When the original file changes, an old copy may remain on the CDN. Sites set caching rules for how long to use a copy and when to replace it. If copies are kept too long, visitors may briefly see outdated content.