i am paying for more than one ip addresses from the cable company, the second is usually cheaper in a business setup.
one cable modem->single switch box->a single router per wan ip address->switch box->a second router behind each first router.
so i have 2 lans with each single ipaddress used.
i place equipment that can access the internet between the first and second router and my business computers behind the second routers.
i decided to have my sme servers behind the second router.
i set the first router's DMZ setting to point to the second router, then port forward specific ports toward the sme server behind the second router.
you can use specific port forwarding on the first router to point to any device between the first and second router.
all routers are the same and each router has port translation features.
routers change, i always buy backup routers of the same once i am satisfied with one by buying and testing.
i do not own a netgear wndr3800 but i think they might be what something you are interested in.
not the only reason, but one reason i use 2 routers is because on many routers, you can only port forward or port translate and forward on a limited number of ports, 20 in my case on my cheap routers.