
RRDtool 'merely' (in the politest possible sense, as it's actually pretty comprehensive) creates graphs from data.
MRTG uses SNMP traps to gather data from IP devices, which it then passes to RRDtool to present in graphical format.
The mod I referred to earlier doesn't use MRTG, but it does use RRDtool to create the graphs.
The 'data gathering' part is bespoke though, although like MRTG, is also perl based.
Edited by deleted (Wed 05-Jan-11 21:23:28)