MRTG requires perl5 and the GD Graphics Library which can be found at http://www.boutell.com/gd. Very easy to use, and quite a lot you can get out of it, although it really only shows the amount of traffic on a network, not the specific types of traffic that are going through link.
MRTG has its limitations but it is not so bad and is definitely easy to use. It is set up to graph two variables on the same axis, being designed just for traffic monitoring; but of course you can do single-variable graphs by setting them both the same, or one to zero. SNMP queries are done internally and it has hooks to query other things as well. You'll probably want to set `WithPeak' and `Options: bits'. It's also a good idea to write some m4 macros to generate the mrtg.cfg once you decide how you want the output to look. It's not the ultimate graphing program but it's free and easy and you'll have it up fast until when and if you can get the ultimate graphing program running. Works well enough. -- Shields, CrossLink.