http://social.technet.microsoft.com/wiki/contents/articles/5292.dp-vs-secondary-site-vs-bdp-in-sccm-2007-vs-sccm-2012.aspx

 

Refer to this Link . 

 

You may also refer to my Blog at :

 

https://sccmconfighelp.wordpress.com/2013/04/25/primary-site-vs-secondary-site-vs-distribution-point-sccm-2012-which-one-to-choose-and-when-to-choose/