Monitoring Bandwidth (transfer) in GB / MB

["Ryan White" <rwhite () collectivenet net>]

I have been trying to search for a way to monitor customers bandwidth
transfer usage by GB. I have not found any method to do this with rrdtool or
mrtg. I could definitely be missing an industry term that I should search
for since google does not return anything useful.

Does anyone have a list or recommendation for such a tool?

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Ryan White
Niuhi, Inc.