In this matter, which is rather vague and embraces many concerns, three types of tools are available:
- Services Monitoring Tools (and Outage Notification)
- Usage Graphing Tools
- Network Management Systems
Nagios is of the first kind, Cricket and MRTG are of the second. Both kinds may happily co-exist, and you often need both, if your network is important to you. It is often useful to know when something is going wrong, but also keep a log of those outage and prevent future ones by carefully analysing the usage.
Yet another type of tools, which may be related, is a tool to manage your network . Two good examples of these are HP OpenView and IBM Tivoli.
This is also slightly related to NIDS.
 configure, extend, … it
This article was first written in July 2003 for the BeezNest technical website (http://glasnost.beeznest.org/articles/35)