This is possibly a stupid question, but the speed of the network interface (i.e. 100mbit or 1000mbit) would not define any bandwidth limitations correct? I'm talking upwards of 500TB per month of data transfer.
That's just the speed at which the ethernet card has negotiated with whatever it's connected to, e.g. a switch. It is completely unrelated to arbitrary bandwidth caps. The speed of the link determines the maximum amount of bandwidth at any given moment, not cumulatively over a period of a month. Does that make sense, or did I misunderstand the question?