I'm *almost* following what you want.
Do you want to get the bandwidth for the "eth0" interfaces for all your routers?
Do you want to get the bandwith for specific interfaces that you specify on a case by case basis?
Do you want to bet the bandwidth for a specific TYPE of interface (MPLS, serial, etc)?
And what do you mean "based on product"?
I'm looking for the same thing no one seems to have an answer to this question.