free traffic monitoring tool for Windows

Bandwidth monitor, bandwidth speed test, bandwidth and traffic monitoring tool for Windows

NetWorx is a simple and free, yet powerful tool that
helps you objectively evaluate your bandwidth situation. You can use it
to collect bandwidth usage data and measure the speed of your Internet
or any other network connection. NetWorx can help you identify possible
sources of network problems

incoming and outgoing traffic is represented on a line chart and logged
to a file, so that you can always view statistics about your daily,
weekly and monthly bandwidth usage and dialup duration.