Multi Router Traffic Grapher (MRTG) is a tool to monitor the traffic
load on network links. MRTG generates HTML pages containing PNG images
which provide a LIVE visual representation of this traffic.
You have a router, you want to know what it does all day long? Then
MRTG is for you. It will monitor SNMP network devices and draw pretty
pictures showing how much traffic has passed through each interface.
Routers are only the beginning. MRTG is being used to graph all sorts
of network devices as well as everything else from weather data to
MRTG is written in perl and works on Unix/Linux as well as Windows and
even Netware systems. MRTG is free software licensed under the Gnu GPL.