BLËSK Network Performance Monitor (NPM) detects, diagnoses and helps resolve performance problems before breakdowns occur. Using Cacti, it collects and analyzes data from routers, switches, servers and other SNMP compatible devices in almost real time, presenting the data in graphs for detailed monitoring.
See the Quick Start guide for an example on how to add a graph in NPM.
There is also a video tutorial available here: NPM Add Graph Tutorial
In the NPM home page, shown above, you can see six tabs at the top of the page: Tree view, List view, Preview view, Tools, Discover and Administration.