Basic command of SNMP:
- GET: The GET operation is a request sent by the manager to the managed device. It is performed to retrieve one or more values from the managed device.
- GET NEXT: This operation is similar to the GET. The significant difference is that the GET NEXT operation retrieves the value of the next OID in the MIB tree.
- GET BULK: The GETBULK operation is used to retrieve voluminous data from large MIB table.
- SET: This operation is used by the managers to modify or assign the value of the Managed device.
- TRAPS: Unlike the above commands which are initiated from the SNMP Manager, TRAPS are initiated by the Agents. It is a signal to the SNMP Manager by the Agent on the occurrence of an event.
- INFORM: This command is similar to the TRAP initiated by the Agent, additionally INFORM includes confirmation from the SNMP manager on receiving the message.
- RESPONSE: It is the command used to carry back the value(s) or signal of actions directed by the SNMP Manager.
This is a sample structure of OD:
Many manufactures can supply custom MIB files for their hardware ,such as temperature , fan speed.
The MIB file is hard to read, they are only meant to be imported, or "compiled " by a Management Station.
Below is an example of Cisco MIB file for environment monitoring.
Cisco MIB information:
Load MIB file:
The files below is F5 MIB file.
We can use MIB Browser to load these file ,and you can see the F5 private OID in the picture.