I'm re-factoring my asp.net application from asp.net 3.5 to 4.0. Also I'm changing url to user friendly url. Example
/product.aspx?id=100 to /product-name/100
All my pages indexed by search engines and the site already 6 years online. I'm planning to do 301 redirect from old pages to new one.
I want to make sure I won't loose the rank and traffic.
Any suggestion how to do it properly?