What does the N750 and N900 do specifically?

I currently own a linksys EA4500, and with this router, and my previous one linksys E4200 V2 I had to enable port forwarding for my device to stay online consistently so I could stream media and access all my files from my iPhone or iPad on the go.  Does this router made by WD make it so you don’t have to activate port forwarding, does it stay online all the time with this router?