ATL Telecom R1-SW Ethernet Switch - Manual (Page 137)

Configuring SNMP and RMON
8-3
SNMP Agent and MIB
The SNMP agent is a network management module running in the managed device. The SNMP
agent responds to SNMP manager requests as follows:
y Get a MIB variable: The SNMP agent initiates this function in response to a request from the NMS. The
agent retrieves the value of the requested MIB variable and responds to the NMS with that value.
y Set a MIB variable: The SNMP agent initiates this function in response to a message from the NMS. The
SNMP agent changes the value of the MIB variable to the value requested by the NMS.
The SNMP agent also sends unsolicited trap messages to notify an NMS that a significant event
has occurred on the agent. Examples of traps conditions include, but are not limited to, when a
port or module goes up or down, when spanning-tree topology changes occur, and when
authentication failures occur.
The MIB is the information base, the SNMP agent must keep available for the managers. This
information base contains objects whose values provide information on the status of the
checked system or objects whose values can be modified by a manager to control the system.
Each object is identified by an Object ID (OID). There are two kinds of MIBs, standard MIB
and enterprise-specific MIB.
SNMP Manager
SNMP Manager is an integrated management module which collects information from SNMP
agent and sometimes sends warning messages depending on the each SNMP agent relations. In
other words, the actual data is collected from SNMP agent and this data will be processed by
management module and saved. To request information or configuration changes, respond to
requests, and send unsolicited alerts, the SNMP manger and SNMP agent use the four messages
(Get, GetNext, Set, trap). For more information on these messages, refer to the following section.