How do you monitor your ISP to measure availability?
A Closer Look at SNMP (Essential SNMP)
SNMP manager and SNMP agent concepts
What is SNMP? | SNMP Agent-Protocol & Port - ManageEngine OpManager
What is Simple Network Management Protocol (SNMP)? - Industrial Networking - Industrial Automation, PLC Programming, scada & Pid Control System
What does the "Link Up" or "Link Down" SNMP Trap monitor? How do I initiate it? | Industrial Ethernet Products: Gigabit Switches, Media Converters, Ethernet Extenders