LibreNMS - Network monitoring system

LibreNMS is an autodiscovering PHP/MySQL/SNMP based network monitoring which includes support for a wide range of network hardware and operating systems including Cisco, Linux, FreeBSD, Juniper, Brocade, Foundry, HP and many more.

Its features include:

• Automatically discover your entire network using CDP, FDP, LLDP, OSPF, BGP, SNMP and ARP.
• Highly flexible alerting system, notify via email, irc, slack and more.
• A full API to manage, graph and retrieve data from your install.
• Generate bandwidth bills for ports on your network based on usage or transfer.
• Stay upto date automatically with bug fixes, new features and more.
• Horizontal scaling to grow with your network.