The canonical application for network monitoring is Nagios; there are quite a few alternatives, though.
Some time ago I was looking for a monitor application too, and nagios didnt fit. it4s incredible slow to respond to multiple (even unrelated) failures. So I ended with GNU mon. It4s perl based, no fancy graphics but very reliable and very scriptable. I use to monitor links with usual ping plugin, but wrote scripts to monitor from room temperature to BGP sessions. -- Christian Lyra PoP-PR/RNP
