I know that: “browsers can download two components in parallel per hostname” example http://www.example.com & http://www.example.org
My question is: can browsers download two components in parallel per subdomain ? http://www.example.com & images.example.com
Yes they can. I’ve just done it myself with a Ruby on Rails application using Rails’ built-in support for multiple asset hosts. They’re all subdomains e.g. asset0.example.com, asset1.example.com etc.