OpenNMS

OpenNMS is an open-source network management platform designed to monitor enterprise networks and provide fault, performance, and service assurance. It is written in Java and runs on Linux and other platforms, delivering scalable monitoring for multi-vendor environments.

OpenNMS collects data from devices and applications via SNMP, ICMP, NetFlow/sFlow, JMX, Syslog, and custom scripts. It includes a poller that periodically queries devices, an event management subsystem that correlates alerts, and a workflow framework that supports incident creation, escalation, and notification. It also provides topology mapping and service health visualization.

The platform stores collected information in a relational database and exposes data through RESTful APIs and a user interface. It offers dashboards, alerting rules, and service-aware views that show the impact of failures across services.

OpenNMS is available in two editions: OpenNMS Horizon, the community edition, and Meridian, the commercial edition with enterprise support and additional features. The Horizon edition is open source and governed by the project’s license; Meridian is maintained by The OpenNMS Group and sold with professional services and SLA-backed support.

In deployment, OpenNMS is designed for large-scale networks, supporting distributed polling, high availability, and clustering. It is used by educational institutions, telecom operators, service providers, and enterprises to monitor multi-vendor equipment from vendors such as Cisco, Juniper, and HP.