bw usage?

["David M. Ramsey" <dmr () webserve net>]

Folks,

I'm interested in learning which tools other people are using to measure
bandwidth usage for co-located client machines on Ethernet switches.

For now I've cobbled together some crude software to regularly 
read SNMP port byte in/out counters from our switches, stashing 
the deltas in a DB for later reporting/analysis.

I'm concerned that the data is misleading, though, in that it will
include LAN broadcast traffic.  Also, customers end up paying 
for other bandwidth that they did not want or induce, like network 
scans, etc. (tough luck?).

We've considered implementing unique customer VLANS to separate
customer broadcast domains, but it seems like that'd be a pain,
would eat up IP addresses, and possibly tax our routers with all of
the ISL/VLAN stuff?

Thanks in advance for any help/hints/pointers/advice you can offer.

Regards, --dmr

David Ramsey
Charlotte, NC