recently I needed test performance of CDN network over my previous hosting. I took me some time to figure it out, so maybe this post can save yours.
I tested CDN77 (a Content Delivery Provider) and their 14 day free trial just to have short opportunity to try out some CDN. These tools can be used with every other CDN network.
1/ If you need to test website loading speed from any particular location around world use http://www.webpagetest.org/. Definitely use Advanced solution and select Native connection.
Output is simple and straightforward, full of helpful insights.
2/ For testing download speed use command line tool wget:
wget --debug --header "Host: 775950798.r.cdn77.net" 220.127.116.11/1.flv
You can also use command traceroute or mtr to see path from your computer to the desired CDN location.
3/ If you want to test load time from whole world (more than 50 locations) on one place give http://just-ping.com/ a shot. First put in your site, then CDN and compare results.
I hope this will be useful! I achieved great improvements in loading and download time. And I don't even speak about Video on Demand solution with instant seeking, which is incredible.