An Overview of CDNs
If you’ve been around WordPress for long, you’ve likely heard of a “CDN.” A CDN, or content-delivery network, is one of the most common parts of speeding up a WordPress site, especially for visitors who are far away from where your site is hosted. But the way this works is often a blackbox to people I talk to. That’s where this great article over at web.dev from Katie Hempenius. She explains all the bits of CDNs I already knew, and much more beyond.
And throughout the writing is crisp and very clear. For those too lazy to read the whole thing—trust me, I TOTALLY understand—here’s an example of her clarity, explaining the highest-level concept—how CDNs help with site performance:
At a high-level, the performance benefits of CDNs stem from a handful of principles: CDN servers are located closer to users than origin servers and therefore have a shorter round-trip time (RTT) latency; networking optimizations allow CDNs to deliver content more quickly than if the content was loaded “directly” from the origin server; lastly, CDN caches eliminate the need for a request to travel to the origin server.