Eric Swanson on Technology Services

Scenario: You request a website that utilizes Yahoo’s User Interface code library by embedding the javascript file http://yui.yahooapis.com/3.0.0/build/yui/yui-min.js in a web page, your browser’s request searches through a network for the server that hosts the file, Yahoo’s Content Delivery Network (CDN) responds as the host and routes your request for the file to the nearest geographical server to your original request, and the server responds with the file.

I digress… Content Delivery Networks (CDN) have been a staple for popular content on the internet since the beginning of web time. Essentially CDNs replicate content to computer servers that are geographically closer to you, so that when you request a very popular file, the request-response communication does not have to travel around the world to get it. In addition to proximity, common files referenced across websites are cached using a single URI/URL (local browser cache, router cache, proxy server caches, and CDN server caches). *This is why you will usually see a file version number in the URL so that newer versions of the file do not have to worry about existing file caches.

So, Microsoft’s AJAX library joined the ranks of CDN notoriety in September 2009 with SSL support released a couple of days ago. Now, any website (including non-Microsoft technology websites) can use Microsoft’s AJAX library with all of the benefits of a CDN. Enjoy!