For CA Unified Infrastructure Management
The SNMP Data Monitoring (snmpcollector) probe associates specific metrics with a device or device component during secondary discovery. The probe implements this behavior by using metric family, vendor certification, and vendor priority files.
Metric Families
A device is subdivided into components by snmpcollector. A component can represent physical components such as CPUs or memory, or logical components such as interface jitter or HTTP response. Metric Families organize all of the metrics that pertain to a component into a comprehensive catalog of metrics.
In most cases, only a subset of the metrics in a metric family are supported by a particular component vendor. For example, a metric family for CPUs contains the metrics cpuUserUtilization, cpuSystemUtilization, and cpuIdleUtilization. A CPU from a particular vendor might only support the cpuSystemUtilization and cpuIdleUtilization metrics.
The following diagram shows an example metric family.
Vendor Certifications
A vendor certification is a library of metric definitions for a specific device from a specific vendor. Many vendor certification files exist in snmpcollector. Each vendor certification file contains device specific:
- Vendor OIDs
Vendor certifications can contain a subset of the OIDs found in the original vendor MIBs.
- Metric definitions
A metric definition is either an OID which is associated with raw data from the device or an expression that uses an OID in a calculation. The metric definitions are used to generate the metrics for a device which you can view in USM.
The following diagram shows how vendor certifications are associated with a metric family.
Vendor Priorities
Vendor priority files list vendor certifications according to specificity. The most specific vendor certifications are at the top of the list and the most generic vendor certifications are at the bottom of the list.
During secondary discovery, snmpcollector sequentially moves through the vendor priority list searching for key OIDs. The vendor certification provides these key OIDs. The first vendor certification that matches the key OIDs is assigned to the device component. Since each vendor certification file is associated with specific metric definitions, the appropriate metrics are generated for a device component. The pollagent probe retrieves the data for the metrics from the device.
The following diagram shows how a vendor priority file identifies the appropriate vendor certifications.
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