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.

• 
• 1.3.6.1.2.1.1 - SNMP MIB-2 System
• 1.3.6.1.2.1.2 - SNMP MIB-2 Interfaces
• 1.3.6.1.2.1.3 - at
• 1.3.6.1.2.1.4 - ip
• 1.3.6.1.2.1.5 - icmp
• 1.3.6.1.2.1.6 - tcp
• 1.3.6.1.2.1.7 - udp
• 1.3.6.1.2.1.8 - egp
• 1.3.6.1.2.1.9 - cmot
• 1.3.6.1.2.1.10 - transmission
• 1.3.6.1.2.1.11 - snmp
• 1.3.6.1.2.1.14 - OSPF Version 2 MIB
• 1.3.6.1.2.1.15 - BGPv4
• 1.3.6.1.2.1.16 - Managed Objects for Bridges
• 1.3.6.1.2.1.17 - Bridge Mib
• 1.3.6.1.2.1.22 - rptrHealth
• 1.3.6.1.2.1.25 - HOST-RESOURCES-MIB, from RFC 1514
• 1.3.6.1.2.1.26 - Ethernet MAU mib
• 1.3.6.1.2.1.27 - Application MIB module
• 1.3.6.1.2.1.28 - MTA MIB module
• 1.3.6.1.2.1.29 - X.500 Directory MIB module
• 1.3.6.1.2.1.31 - ifMib
• 1.3.6.1.2.1.33 - upsMIB
• 1.3.6.1.2.1.34 - snaNode
• 1.3.6.1.2.1.38 - mdmMib
• 1.3.6.1.2.1.41 - sdlcStatus
• 1.3.6.1.2.1.43 - Printer-MIB
• 1.3.6.1.2.1.47 - entity-mib
• 1.3.6.1.2.1.69 - docsDev
• 1.3.6.1.2.1.92 - notificationLogMIB

OID:

This is a sample structure of OD:

Iso(1).org(3).dod(6).internet(1).private(4).transition(868).products(2).chassis(4).card(1).slotCps(2)-cpsSlotSummary(1).cpsModuleTable(1).cpsModuleEntry(1).cpsModuleModel(3).3562.3

or just:

1.3.6.1.4.868.2.4.1.2.1.1.1.3.3562.3

Private OID:

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:

http://snmp.cloudapps.cisco.com/Support/SNMP/do/BrowseMIB.do?local=en&step=2

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.

参考