Each SNMP object has a name and numeric identifier. For example, in the system group, the network object named SysDescr with object identifier 1.3.6.1.2.1.1.1 contains a description of the device.
An object can have one or more instances, depending on the configuration of the monitored device. For example, a device can have two network adapters, in which case there will be two instances of the ifPhysAddress object, which has object identifier 1.3.6.1.2.1.2.2.1.6. In this case, you need to specify an instance number at the end of the object identifier (such as 1.3.6.1.2.1.2.2.1.6.1). If you do not specify an instance, it defaults to zero.