Network monitoring is a computer network’s systematic effort to detect slow or failing network components, such as overloaded or crashed/frozen servers, failing routers, failed switches or other problematic devices. In the event of a network failure or similar outage, the network monitoring system alerts the network administrator (NA). Network monitoring is a subset of network management.
Network monitoring is generally carried out through software applications and tools. Network monitoring services are widely used to detect whether a given Web server is functioning and connected properly to networks worldwide. Many servers that perform this function provide a more complete visualization of both the Internet and networks.
– definition from Techopedia