What gives. Am I wrong in thinking T, DS, and OC lines are full-duplex? Am I wrong in thinking that if you are paying for 1Mbit, you should be charged on the highest, incoming or outgoing, if you are on a full-duplex 100mbit line and not both? Why would a provider charge for "actual transfer" both ways if you're on a full-duplex line? Aren't they themselves getting charged for the highest, in or out? Maybe if those lines were half-duplex I would understand, but that would be inefficient. I'm not saying maxing the line at 100mbit in and out at one time (that would be chaotic), but 80% should be fine...

Anyone (ideally colo/bandwidth providers) have any answers or opinions? Supporting documentation would be great, too, as I can't find any...

Technically, yes, you're wrong. Such transmission lines are always simplex. But in practice they are usually installed in balanced pairs.

But as for how you're charged... that's between you and your upstream provider. In the end, there really isn't any "right" or "wrong" way.

Originally posted by cperciva
Such transmission lines are always simplex. But in practice they are usually installed in balanced pairs.
Well yes, I know, but if I purchase a full T3/DS3 from a provider, do I get 45mbit total, or 45mbit up and 45mbit down (assume 100% for kicks)? I guess that was my initial question.

You'd get 45Mbps in each direction.

Both Directions!

I think what he means is, are tX/OC-X full duplex as in you can send out 45 Mbps at the same time as receiving 45Mbps. ( a total of 90Mbps )