Device Model System Overview

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What are Device Models?

• SNMP OID mappings - Which OIDs to collect and how to interpret them
• Data collection sections - Interface stats, system health, environmental sensors
• Alert thresholds - When to generate notifications
• Graph definitions - How to visualize collected data
• Device identification - How to match devices using systemObjectID

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Model Structure

%hash = (
  'systemHealth' => {
    'sys' => {
      'env-temp' => {
        'indexed' => 'entSensorStatus',
        'headers' => 'tempDescr,currentTemp',
        'snmp' => {
          'tempDescr' => {
            'oid' => 'entPhysicalDescr',
            'title' => 'Description'
          },
          'currentTemp' => {
            'oid' => 'entSensorValue',
            'title' => 'Current Temp (C)'
          }
        }
      }
    },
    'rrd' => {
      'env-temp' => {
        'indexed' => 'true',
        'graphtype' => 'env-temp',
        'snmp' => {
          'currentTemp' => {
            'oid' => 'entSensorValue'
          }
        }
      }
    }
  },
  'alerts' => {
    'env-temp' => {
      'tempStatus' => {
        'type' => 'threshold-rising',
        'threshold' => {
          'Critical' => '95',
          'Major' => '90'
        }
      }
    }
  }
);

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Model Types

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Base Models (Model-*.nmis)

• System identification (sysObjectID patterns)
• System health sections to collect
• Interface collection settings
• Device-specific features

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Common Models (Common-*.nmis)

• Common-Cisco-cbqos.nmis - Class-based QoS monitoring
• Common-Cisco-power.nmis - Power supply monitoring
• Common-Cisco-temp.nmis - Temperature sensor monitoring
• Common-Huawei-NQA.nmis - Network Quality Analysis
• Common-Juniper-jnxCoS.nmis - Class of Service statistics

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Device Identification

'systemHealth' => {
  'sys' => {
    'sysObjectID' => {
      'oid' => '1.3.6.1.2.1.1.2.0'
    }
  }
}

'Cisco' => {
  'order' => {
    '10' => {
      'CiscoRouter' => 'cisco.*router',
      'CiscoSwitch' => 'cisco.*switch',
      'CiscoNexus' => 'nexus'
    }
  }
}

​

SNMP OID Mapping

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Using MIB Names

'tempDescr' => {
  'oid' => 'entPhysicalDescr',
  'title' => 'Description'
}

​

Using Numeric OIDs

'PowerOperStatus' => {
  'oid' => '1.3.6.1.4.1.9.9.117.1.1.2.1.2',
  'snmpObjectName' => 'cefcFRUPowerOperStatus'
}

​

Value Replacement

'tempStatus' => {
  'oid' => 'entSensorStatus',
  'replace' => {
    '1' => 'ok',
    '2' => 'unavailable',
    '3' => 'nonoperational'
  }
}

​

Model Sections

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systemHealth

• sys - Displays values in the GUI
• rrd - Stores time-series data for graphing

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interface

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alerts

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database

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heading

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Supported Vendor Categories

• Cisco - IOS, IOS-XE, IOS-XR, NX-OS devices
• Huawei - VRP platform devices
• Juniper - JUNOS devices
• F5 - BIG-IP load balancers
• Windows - WMI-based monitoring
• SynologyNAS - NAS devices
• NutanixAHV - Hypervisor monitoring
• Host Resources - Generic SNMP devices
• Generic - Universal monitoring via standard MIBs

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Model Inheritance

'-common-' => {
  'class' => {
    'Cisco-cbqos' => {
      'common-model' => 'Cisco-cbqos'
    },
    'Cisco-power' => {
      'common-model' => 'Cisco-power'
    }
  }
}

​

Data Collection Process

1. Device Discovery - NMIS queries sysObjectID and matches to model
2. Model Loading - Base model + common models are loaded
3. SNMP Collection - OIDs defined in ‘sys’ and ‘rrd’ sections are polled
4. Data Storage - RRD files store time-series metrics
5. Alert Evaluation - Thresholds are checked against current values
6. Graph Generation - RRD data is rendered as graphs

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Next Steps

• Cisco Device Models - CBQoS, IP SLA, power, temperature
• Huawei Device Models - NQA, HQoS, CBQoS monitoring
• Juniper Device Models - jnxCoS, operations monitoring
• Creating Custom Models - Build your own device models