OID Groups

Object Identifier (OID) groups are optional monitor specific parameters. They define sets of one or more OIDs of a device's Management Information Base (MIB) objects. The SNMP monitor uses the OID groups to retrieve data from those MIB objects whose OIDs appear in a specified OID group.

The details of the MIB objects from which the monitor extract data are as follows:

• OID Value
  The numerical identifier of the MIB object instance expressed using either ASN.1 notation, for example .1.3.6.1.2.1.1.2.0, or the object’s name, for example sysObjectID.0

  Note: When using ASN.1 notation, you must include the leading . character in the OID.

  Note: You may only use an object’s instance name to specify the OID value if the MIB document that defines the name is accessible by the monitor. The default directory for MIB documents is $ISHOME/mibs.
• OID Name

  The name of the MIB object, for example sysObjectID. This name is used in service level classifications and in $oidNamen monitor elements.

• OID Unit
  The units of the data contained in the MIB object. For example, seconds, bytes, or bits per second (BPS). Set to BPS to enable bits per second calculation for the OID. Bits per second values are calculated as:

  current_poll_value - prev_poll_value) / poll_interval * 8

• Selector
  The index value of the MIB object. The following table shows an example that results in the selector searching all the ifDescr rows for the value FastEthernet0/1, giving a row index of 2. Then the row ifPhysAddress.2 is queried and the value 0:6:53:34:d2:a1 is returned. In this way the index 2 is not directly specified, so if the index for FastEthernet0/1 changes, the OID groups do not need to be re-configured.

  Table 1. Use of the index value

  MIB object	MIB object value
  OID value	ifPhysAddress
  OID name	FastEthernet0/1PhysicalAddress
  OID unit	string
  Selector	ifDescr=FastEthernet0/1