I would recommend using Cacti for interface speed monitoring.
It is available at www.cacti.net
–Colin
Cacti does the job graphically extremely well (best rrd front-end ever
IMO), but it has no actual reporting tools and it's all rrd based so not
extremely handy for long-term accounting and historical data. The 95%
and accumulated datatraffic ar generated by the interface, not stored in
the actual rra's itself. In terms of reporting there's nothing there
really, it's just poll -> store in rra -> graph
Erik