Monitoring bandwidth usage
There are times when I need to monitor the bandwidth that I have used for the month and I have found that of the available free software that I have found AnalogX NetStat Live seems to do a fairly reasonable job.
It monitors the bandwidth on one machine only and if you have more than one machines on the network then you need to add up the bandwidth.
Another problem is that when you have a file server it will also record the bandwidth between transfers to the local file server which makes it a bit inaccurate.
Another bandwidth monitoring software that I have used at one stage is ShaPlus Bandwidth Meter .
This one doesn't show as much information as the NetStat Live but you also get a fairly good idea of how much broadband bandwidth you have used.
Lastly another application worth a look is Netmeter. This hasn't been updated for a while.
I am sure there are other free bandwidth monitoring tools but I have found that one of these three is basically adequate at times when I need to monitor bandwidth usage.