Metric extensions provide you with the ability to extend Oracle's monitoring capabilities to monitor conditions specific to your IT environment. For example, you can create a new metric for a host target type. Use an SNMP Adapter to allow Enterprise Manager Management Agents to query native SNMP agents on target hosts for Management Information Base (MIB) variable information to be used as the metric data.
For more information about Metric Extensions and the SNMP Adapter, see Using Metric Extensions.