Any system admin working in a service provider network would certainly agree that Cacti is one of the most widely used tools in network management solutions. It is open source, has built in user authentications and user permission features, shipped with frequently used graph templates like bandwidth, 95th percentile, hard disk usage, CPU usage, load average, RAM statistics and many more. Cacti also supports 3rd party templates and plugins. If those are not enough, one can write and use one’s own templates, and that is the beauty of open source software.