ENTITY-SENSOR-MIB

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Organization: IETF Entity MIB Working Group

Last Updated: 2002-12-16

Category: Hardware and Environment

Description: An extension of ENTITY-MIB adding support for physical sensors on networking equipment, so environmental parameters like temperature, voltage, and fan speed can be monitored.

IPNetwork Monitor uses several OIDs from this MIB in network discovery and polling the applicable devices. Start monitoring ENTITY-SENSOR-MIB with a free 30-day trial of IPNetwork Monitor.

What Is ENTITY-SENSOR-MIB?

ENTITY-SENSOR-MIB is a vendor-neutral IETF standards-track module (RFC 3433) that extends the ENTITY-MIB to describe physical sensors mounted on networking equipment components. It exposes data on sensor type, measurement scale, precision, current reading, operational status, and the timestamp of the last update, covering environmental parameters like temperature, voltage, current, and fan speed. It is squarely a hardware health monitoring MIB: administrators use it to track whether temperature sensors, power-supply voltage sensors, and fan tachometers are reading normal values or reporting a fault/out-of-range condition on physical entities such as chassis, modules, and power supplies. Because entPhySensorTable entries are indexed against entPhysicalIndex, this MIB has a hard dependency on ENTITY-MIB for entity identification. It is deployed on any router, switch, or chassis-based device that reports physical sensor readings via SNMP, typically polled by NMS platforms for environmental alerting, and engineers researching entity-sensor-mib object definitions will find RFC 3433 the canonical reference for how those readings are structured.

IPNetwork Monitor allows you to monitor SNMP objects defined in ENTITY-SENSOR-MIB. Use the built-in SNMP Monitoring Browser to explore available variables, view their current values and descriptions, and select the objects you want to monitor. You can then create SNMP monitors, configure thresholds, and receive alerts when monitored values change.

Supported Devices

vendor-neutral, standards-based MIB, not tied to a specific manufacturer
modular routers and switches
chassis-based network equipment

Monitoring Examples

An admin polls entPhySensorTable, joining entPhySensorValue (scaled by entPhySensorScale and entPhySensorPrecision) with entPhySensorType to distinguish a temperature sensor from a voltage or fan-speed sensor on a given entPhysicalIndex. A rising entPhySensorValue on a temperature-type sensor combined with entPhySensorOperStatus moving from 'ok' to 'nonoperational' would flag an overheating card or failed fan before a hard failure. entPhySensorValueTimeStamp and entPhySensorValueUpdateRate help the poller confirm the sensor reading is fresh rather than stale.

What Can Be Monitored

temperature sensor readings
voltage sensor readings
fan speed
sensor operational status
sensor value precision/scale
sensor reading freshness (timestamp/update rate)

Imported Objects

From ENTITY-MIB

entPhysicalIndex	OBJECT-TYPE
entityPhysicalGroup	OBJECT-GROUP

From SNMP-FRAMEWORK-MIB

SnmpAdminString

From SNMPv2-CONF

MODULE-COMPLIANCE
OBJECT-GROUP

From SNMPv2-SMI

Integer32
MODULE-IDENTITY
OBJECT-TYPE
Unsigned32
mib-2

From SNMPv2-TC

TEXTUAL-CONVENTION
TimeStamp

OIDs

OID symbolic	OID numeric	Type	Access	Description
entitySensorCompliance	1.3.6.1.2.1.99.3.1.1			Describes the requirements for conformance to the Entity Sensor MIB module.
entitySensorCompliances	1.3.6.1.2.1.99.3.1
entitySensorConformance	1.3.6.1.2.1.99.3
entitySensorGroups	1.3.6.1.2.1.99.3.2
entitySensorMIB	1.3.6.1.2.1.99			This module defines Entity MIB extensions for physical sensors. Copyright (C) The Internet Society (2002). This version of this MIB module is part of RFC 3433; see the RFC itself for full legal notices.
entitySensorObjects	1.3.6.1.2.1.99.1
entitySensorValueGroup	1.3.6.1.2.1.99.3.2.1			A collection of objects representing physical entity sensor information.
entPhySensorEntry	1.3.6.1.2.1.99.1.1.1		not-accessible	Information about a particular physical sensor. An entry in this table describes the present reading of a sensor, the measurement units and scale, and sensor operational status. Entries are created in this table by the agent. An entry for each physical sensor SHOULD be created at the same time as the associated entPhysicalEntry. An entry SHOULD be destroyed if the associated entPhysicalEntry is destroyed.
ENT entPhySensorOperStatus	1.3.6.1.2.1.99.1.1.1.5	EntitySensorStatus	read-only	The operational status of the sensor.
ENT entPhySensorPrecision	1.3.6.1.2.1.99.1.1.1.3	EntitySensorPrecision	read-only	The number of decimal places of precision in fixed-point sensor values returned by the associated entPhySensorValue object. This object SHOULD be set to '0' when the associated entPhySensorType value is not a fixed-point type: e.g., 'percentRH(9)', 'rpm(10)', 'cmm(11)', or 'truthvalue(12)'. This object SHOULD be set by the agent during entry creation, and the value SHOULD NOT change during operation.
ENT entPhySensorScale	1.3.6.1.2.1.99.1.1.1.2	EntitySensorDataScale	read-only	The exponent to apply to values returned by the associated entPhySensorValue object. This object SHOULD be set by the agent during entry creation, and the value SHOULD NOT change during operation.
entPhySensorTable	1.3.6.1.2.1.99.1.1		not-accessible	This table contains one row per physical sensor represented by an associated row in the entPhysicalTable.
ENT entPhySensorType	1.3.6.1.2.1.99.1.1.1.1	EntitySensorDataType	read-only	The type of data returned by the associated entPhySensorValue object. This object SHOULD be set by the agent during entry creation, and the value SHOULD NOT change during operation.
STR entPhySensorUnitsDisplay	1.3.6.1.2.1.99.1.1.1.6	SnmpAdminString	read-only	A textual description of the data units that should be used in the display of entPhySensorValue.
ENT entPhySensorValue	1.3.6.1.2.1.99.1.1.1.4	EntitySensorValue	read-only	The most recent measurement obtained by the agent for this sensor. To correctly interpret the value of this object, the associated entPhySensorType, entPhySensorScale, and entPhySensorPrecision objects must also be examined.
TIM entPhySensorValueTimeStamp	1.3.6.1.2.1.99.1.1.1.7	TimeStamp	read-only	The value of sysUpTime at the time the status and/or value of this sensor was last obtained by the agent.
U32 entPhySensorValueUpdateRate	1.3.6.1.2.1.99.1.1.1.8	Unsigned32	read-only	An indication of the frequency that the agent updates the associated entPhySensorValue object, representing in milliseconds. The value zero indicates: - the sensor value is updated on demand (e.g., when polled by the agent for a get-request), - the sensor value is updated when the sensor value changes (event-driven), - the agent does not know the update rate.

RFC description

Extends ENTITY-MIB with support for physical sensors on networking equipment, enabling monitoring of environmental parameters such as temperature, voltage, and fan speed.

Start monitoring Chassis-based router/switch with physical sensors (vendor-neutral IETF standard RFC 3433) with a free 30-day trial of IPNetwork Monitor. Import MIBs, browse SNMP OIDs, create custom SNMP monitors, configure alerts, and monitor any SNMP-enabled network device from a single console.

Download ENTITY-SENSOR-MIB

What Is ENTITY-SENSOR-MIB?

Supported Devices

Monitoring Examples

What Can Be Monitored

This MIB depends on

Related MIBs

RFC description