home reouter basics

I’ve running a home ADSL router.
What I need to know is what are does all the the various setting mean?
I know that there’s are hundred’s of routers out there, so one can not give specifics. But anything would help with this problem.

Example: “VPI/VCI” settings
“ATM/VCI pool” what are these setting there
“LLC” setting’s.

There’s obvisouly quite a few more, but these are the main one’s.