SNMP concepts:

      The paragraph gives a brief description of the SNMP concepts needed to understand this documentation.

      SNMP

      (Simple Network Management Protocol) is a protocol used to poll or check a device (computer, router, measurement instrument, UPS, etc.) remotely via a computer network.

      The SNMP agent

      collects information concerning a device to be checked, and transmits information to the device.

      The SNMP manager

      uses this information by communicating with the agent via the network with the SNMP protocol (which is based on the UDP/IP protocol to transport the information).

      SNMP defines the following three operations:

      • reading by the manager of an MIB object value (GET and GETNEXT requests),
      • writing by the manager of an MIB object value (SET request),
      • notification of warnings by the agent (traps intended for the manager).

      The community name is used in the communication between the manager and the agent to perform an access check on the MIB information. The managers belonging to the community of an agent are likely to poll it, instruct it and to receive the traps transmitted by it.

      For some systems, there may be, for the same agent, one community authorized to poll it and another authorized to check it by updating its MIB.

      The MIB
      (Management Information Base) is the information base which the agent must keep available for the managers. This information base can contain objects whose values provide information on the status of the device checked or objects whose values can be modified by a manager to control the device. Also, the agent can transmit spontaneous messages to a manager to indicate an event.