Simple Network Management Protocol (SNMP) is an Internet-standard protocol for managing devices on IP networks. Generally, SNMP is used in systems of network equipment control. The following types of devices support SNMP: routers, hubs, servers, workstations, UPSs, etc.
The SNMP plugin supports versions V1 and V2 of the standard, and can operate in two modes: SNMP device or SNMP-Trap device .
The plugin is added using the 'Add Protocol' command :
Using the 'Add Device' command , devices can be added to the node (plugin):
There are two device types in the SNMP plugin:
SNMP device – a mode of a SNMP network manager. OPC server sends requests to the IP address specified, receives replies, and writes values received into tags.
SNMP-TRAP device – a mode of reception of SNMP traps. A SNMP trap is a specific signal a SNMP device sends. Generally, devices send such signals in order to inform a network manager about critical situations (router failure, UPS supply failure, etc.). In this mode, OPC server receives trap signals from SNMP devices, filters requests according settings a user configures, and writes values into tags.