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<< Click to Display Table of Contents >> Navigation: ELM Console (MMC) > Monitoring and Management > Agents and Monitors Library > All Monitors > SNMP Monitor |
The Simple Network Management Protocol (SNMP) communicates management information between network management stations and agents, and is defined in RFC 1157.
The ELM Server can listen for and receive SNMP traps from any SNMP-compliant system or device on your network. Traps are treated as events; they will appear in event views, they will be stored in the database, and you can assign notification methods to trigger when any SNMP trap is received. By default, the Windows SNMP Service listens on UDP port 162, the default SNMP Trap port.
An ELM Agent can run an SNMP Monitor to query an SNMP Object ID (OID) and trigger an action if the value becomes greater than, less than or equal to a user configured value. The SNMP Monitor includes an object browser for you to query the namespace on an SNMP-capable device, and walk the SNMP tree to select the specific OID for monitoring.
See the ELM SNMP Notification Method for details about using ELM to send an SNMP trap, or put an SNMP OID value.
Every SNMP-capable device includes manageable objects that are defined in one or more Management Information Bases (MIBs). Manageable objects include network identification, statistics, protocol information, performance data, and hardware and software configuration details. Each object within an MIB is identified by its object-identifier (OID), which is unique.
ELM Enterprise Manager includes an SNMP Monitor that will query an SNMP Object ID (OID) and then compare the result to a specified value. If the comparison yields a true, then the Warning Action is triggered. If the comparison yields a false, the Success Action is triggered. If the SNMP Monitor is unable to retrieve a value, the Failure Action is triggered. The SNMP Monitor includes an object browser and MIB browser for selecting the OID.
There are several settings for SNMP Monitors.
•Host Computer - The network name or IP address of the SNMP agent to be walked when the Display Objects from computer/community button is clicked.
•Community - The SNMP Community recognized by the SNMP agent. The Windows SNMP service on the ELM Server computer must be configured to use this Community as well.
•Timeout (milliseconds) - The amount of time the ELM SNMP Monitor will have the Windows SNMP Service wait for a response from the SNMP agent between retries.
•Retries - The number of attempts the ELM SNMP Monitor will have the Windows SNMP Service make contacting the SNMP agent before giving up and triggering the Failure Action.
•Display Objects from computer/community - Queries the specified Host Computer and Community for SNMP OIDs and values. Depending on network conditions, the SNMP Agent and the size of the namespace, the query may take several minutes. When complete, the root of the SNMP namespace will appear in the large Object Tree Browser window.
Note
By adding the registry value HKEY_LOCAL_MACHINE\SOFTWARE\TNT Software\ELM Enterprise Manager\7.5.0\Settings\SnmpRootOID on the ELM Console computer, you can specify an OID root different from .1.3.6.1 when Display Objects from a computer/community is clicked in an SNMP Monitor Item or SNMP OID Notification Method. The root OID must be in numeric form.
•Object Tree Browser - Once data is retrieved from the SNMP Agent, the tree can be expanded and collapsed by clicking on the plus (+) and minus (-) controls. When a branch or leaf node is selected, the Object Identifier is displayed. If a leaf node is selected, the value returned by the SNMP Agent is displayed.
•Object Identifier - When a branch or node is selected in the Object Tree Browser window, the corresponding Object Identifier (OID) is displayed here. If the OID is known, it can be entered into this field. It should be typed in dotted numeric format, typically starting with .1.3.6.1.
•Condition - The criterion used by the SNMP Monitors to compare the OID value with the specified value.
•Value - This field has two uses:
•When a leaf node is selected in the Object Tree Browser window, the most recently retrieved value for that leaf node will be displayed here. To refresh the values, click the Object Tree Browser button again.
•This field is used to enter the value used by the SNMP Monitor to evaluate the Condition.
•Execute configured Action(s) for every warning and failure - Check this box to configure the SNMP Monitor to trigger repeated Warning and Failure Actions.
During install, Windows copies a compiled MIB library called MIB.bin into the system32 directory. This file provides OID-to-name translation for a portion of the OID namespace tree. It does not generally include the namespace used by third-party SNMP agents. ELM can read vendor-provided MIB files and add to the namespace provided by the Windows SNMP service. When ELM is installed, it creates a MibFiles sub-directory for third-party MIB files. Place the vendor-supplied MIB file in the MibFiles folder, and use the MIB Files browser to select them. The Add button in the MIB Files Browser can also be used to put a copy of vendor-supplied MIB files in the MibFiles folder.
•Success 5551 - The retrieved OID value comparison with the configured value yielded a false.
•Warning 5552 - The retrieved OID value comparison with the configured value yielded a true.
•Failure 5574 - The SNMP Monitor failed to retrieve the configured OID value.
Displays the Monitoring Categories to which the Monitor item is assigned. Click to select or deselect Monitoring Categories. Click New to create or Properties to Edit Monitoring Categories.
Displays the Agents to which the Monitor item is assigned. Click to select or deselect individual agents. Click New to deploy an agent or Properties to View/Edit an existing agent.
Displays the Scheduled Interval and Scheduled Hours settings which control the frequency for the Monitor Item.
Specify the interval at which the monitoring, polling or action is to occur. Depending on the Monitor Item type, Items can be scheduled in interval increments of Seconds, Minutes, Hours and Days. The Scheduled Interval is relative to the top of the hour or top of the minute. For example, if a Scheduled Interval is configured for 10 minutes, the Monitor Item will execute at hh:10:00, hh:20:00, hh:30:00, hh:40:00, hh:50:00, h1:00:00, etc. If a Scheduled Interval is configured for 15 seconds, the Monitor Item will execute at hh:00:15, hh:00:30, hh:00:45, hh:01:00, hh:01:15, etc.
Select the days and/or hours this item is active. By default, the schedule is set to ON for all hours and all days. Mouse clicks toggle squares between ON and OFF. Clicking on an individual square will toggle the active schedule for that hour. Clicking on an hour at the top of the grid, or on a day of the week at the left of the grid will toggle the corresponding column or row. Keyboard equivalents are the arrow keys and the space bar.