What is network monitoring and what tools are used?

Network monitoring is the continuous process of observing network performance, availability, and health to detect issues, ensure SLAs, and plan capacity. Monitoring covers: device availability (is the router/switch up?), bandwidth utilization (how much of the link capacity is used?), latency/packet loss, error rates, interface statistics, and security events. Technologies: SNMP (polling device metrics), NetFlow/sFlow/IPFIX (traffic flow analysis — who is talking to whom), Syslog (centralized log collection), ICMP monitoring (availability checks), WMI/API (Windows/cloud monitoring). Popular tools: Nagios/Icinga (open-source alerting), Zabbix (open-source, comprehensive), PRTG (user-friendly), SolarWinds NPM (enterprise), Grafana + InfluxDB (modern, time-series visualization), Wireshark (packet-level analysis). Proactive monitoring reduces MTTR (Mean Time to Resolution) and prevents outages.