NOCOL/SNIPS (Network Operation Center On-Line) is a network monitoring
package that runs on Unix platforms and is capable of monitoring network and
system variables such as ICMP or RPC reachability, RMON variables,
nameservers, ethernet load, port reachability, host performance, SNMP traps,
modem line usage, appletalk & novell routes/services, BGP peers, syslog
files, etc. The software is extensible and new monitors can be added easily.

The software consists of a number of individual, standalone monitoring agents
that poll the various network and system parameters and put it into a common
data format.  All the monitors have a common display and postprocessing
interface (such as logging, notification, etc.). The design allows running
just one set of monitoring agents and *any* number of display agents, and all
of the displays see the same consistent set of data. Additionally, each event
is assigned a severity (determined by comparing against user defined threshold
values) which is gradually escalated, thus preventing false alarms and a
customized priority notification based on the severity. There are four
severity levels ranging from Critical thru Info, and each event typically
steps through each one of these severities until it reaches its maximum
allowed level.