ENTITY-MIB

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Organization: IETF ENTMIB Working Group

Last Updated: 2005-08-10

Category: Hardware and Environment

Description: Provides management information about the physical and logical components of a system, including hardware inventory such as fans, sensors, modules, serial numbers, and model information.

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

What Is ENTITY-MIB?

ENTITY-MIB is a vendor-neutral IETF standards module (RFC 6933) that provides a physical and logical inventory model for representing the components of a networking device — chassis, modules, power supplies, fans, sensors, and ports — as entries in the entPhysicalTable. It exposes hardware inventory data including component descriptions, vendor type, physical containment hierarchy, and component class (entPhysicalDescr, entPhysicalVendorType, entPhysicalContainedIn, entPhysicalClass, entPhysicalParentRelPos) -- with the entity-mib entPhysicalDescr OID serving as the primary human-readable label for each entry -- as well as revision identifiers (entPhysicalHardwareRev, entPhysicalFirmwareRev, entPhysicalSoftwareRev). This makes it a central module for monitoring hardware and software status: an operator can enumerate every physical component in a chassis, confirm which slot a module is inserted in, and verify hardware, firmware, and software revision levels are consistent across redundant components such as fans, power supplies, or line cards. Many vendor-specific hardware monitoring MIBs, for environment, power, and sensor data, reference entPhysicalIndex from this module to associate their own readings with a specific physical component, making ENTITY-MIB a common dependency for hardware-health MIBs. It is deployed on virtually any modular or chassis-based networking device — routers, switches, and multi-slot platforms — where representing physical component inventory and hierarchy is needed.

IPNetwork Monitor allows you to monitor SNMP objects defined in ENTITY-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
applies to any modular or chassis-based networking device (routers, switches)

Monitoring Examples

An administrator would walk entPhysicalTable/entPhysicalEntry to enumerate all physical components in a chassis, checking entPhysicalClass to distinguish a fan tray or power supply from a line card, and entPhysicalContainedIn to confirm which parent slot each sub-component belongs to. They would compare entPhysicalHardwareRev and entPhysicalFirmwareRev across redundant power supplies or modules to catch a mismatched firmware version after a partial upgrade, and check entPhysicalName to identify the specific component (for example 'Fan Tray 1') referenced in an alert from a vendor-specific environment MIB that uses the same entPhysicalIndex.

What Can Be Monitored

physical component inventory
component containment hierarchy (slot/parent relationships)
hardware revision level
firmware revision level
software revision level
component vendor type and class

Imported Objects

From SNMP-FRAMEWORK-MIB

SnmpAdminString

From SNMPv2-CONF

MODULE-COMPLIANCE
OBJECT-GROUP

From SNMPv2-SMI

Integer32
MODULE-IDENTITY
OBJECT-TYPE
mib-2

From SNMPv2-TC

DateAndTime
RowStatus
TEXTUAL-CONVENTION
TruthValue

OIDs

OID symbolic	OID numeric	Type	Access	Description
entityGeneral	1.3.6.1.2.1.47.1.4
entityGeneralGroup	1.3.6.1.2.1.47.2.2.7			General entity objects.
entityLogical	1.3.6.1.2.1.47.1.2
entityLogical2Group	1.3.6.1.2.1.47.2.2.5			Logical entity group v2.
entityLogicalGroup	1.3.6.1.2.1.47.2.2.2			Logical entity objects.
entityMapping	1.3.6.1.2.1.47.1.3
entityMappingGroup	1.3.6.1.2.1.47.2.2.6			Entity mapping objects.
entityMIB	1.3.6.1.2.1.47			The Entity MIB (Version 3).
entityMIBCompliances	1.3.6.1.2.1.47.2.1
entityMIBConformance	1.3.6.1.2.1.47.2
entityMIBGroups	1.3.6.1.2.1.47.2.2
entityMIBObjects	1.3.6.1.2.1.47.1
entityPhysical	1.3.6.1.2.1.47.1.1
entityPhysical2Group	1.3.6.1.2.1.47.2.2.3			Additional physical entity objects.
entityPhysical3Group	1.3.6.1.2.1.47.2.2.4			Physical entity group v3.
entityPhysicalGroup	1.3.6.1.2.1.47.2.2.1			Physical entity objects.
OCT entLogicalCommunity	1.3.6.1.2.1.47.1.2.1.1.4	OCTET STRING	read-only	An SNMPv1 or SNMPv2C community-string.
OCT entLogicalContextEngineID	1.3.6.1.2.1.47.1.2.1.1.7	OCTET STRING	read-only	The authoritative SNMP engine identifier.
STR entLogicalContextName	1.3.6.1.2.1.47.1.2.1.1.8	SnmpAdminString	read-only	The SNMP context name.
STR entLogicalDescr	1.3.6.1.2.1.47.1.2.1.1.2	SnmpAdminString	read-only	A textual description of the logical entity.
entLogicalEntry	1.3.6.1.2.1.47.1.2.1.1		not-accessible	Entry for a logical entity.
I32 entLogicalIndex	1.3.6.1.2.1.47.1.2.1.1.1	Integer32	read-only	The value of this object uniquely identifies the logical entity.
entLogicalTable	1.3.6.1.2.1.47.1.2.1		not-accessible	This table contains one row per logical entity.
OCT entLogicalTAddress	1.3.6.1.2.1.47.1.2.1.1.5	OCTET STRING	read-only	The transport service address for this logical entity.
OID entLogicalTDomain	1.3.6.1.2.1.47.1.2.1.1.6	OBJECT IDENTIFIER	read-only	Indicates the kind of transport service.
OID entLogicalType	1.3.6.1.2.1.47.1.2.1.1.3	OBJECT IDENTIFIER	read-only	An indication of the type of logical entity.
STR entPhysicalAlias	1.3.6.1.2.1.47.1.1.1.1.14	SnmpAdminString	read-write	This object is an 'alias' name for the physical component.
STR entPhysicalAssetID	1.3.6.1.2.1.47.1.1.1.1.15	SnmpAdminString	read-write	This object is a user-assigned asset tracking identifier.
PHY entPhysicalClass	1.3.6.1.2.1.47.1.1.1.1.5	PhysicalClass	read-only	An indication of the general hardware type of the physical component.
PHY entPhysicalContainedIn	1.3.6.1.2.1.47.1.1.1.1.4	PhysicalIndexOrZero	read-only	The value of entPhysicalIndex for the physical entity which 'contains' this physical component.
STR entPhysicalDescr	1.3.6.1.2.1.47.1.1.1.1.2	SnmpAdminString	read-only	A textual description of physical component.
entPhysicalEntry	1.3.6.1.2.1.47.1.1.1.1		not-accessible	Entry for a physical component.
STR entPhysicalFirmwareRev	1.3.6.1.2.1.47.1.1.1.1.9	SnmpAdminString	read-only	The vendor-specific firmware revision string for the physical component.
STR entPhysicalHardwareRev	1.3.6.1.2.1.47.1.1.1.1.8	SnmpAdminString	read-only	The vendor-specific hardware revision string for the physical component.
PHY entPhysicalIndex	1.3.6.1.2.1.47.1.1.1.1.1	PhysicalIndex	read-only	The index for this entry.
T/F entPhysicalIsFRU	1.3.6.1.2.1.47.1.1.1.1.16	TruthValue	read-only	This object indicates whether or not this physical component is considered a field replaceable unit (FRU).
DAT entPhysicalMfgDate	1.3.6.1.2.1.47.1.1.1.1.17	DateAndTime	read-only	This object contains the date of manufacturing of the managed component.
STR entPhysicalMfgName	1.3.6.1.2.1.47.1.1.1.1.12	SnmpAdminString	read-only	The name of the manufacturer of this physical component.
STR entPhysicalModelName	1.3.6.1.2.1.47.1.1.1.1.13	SnmpAdminString	read-only	The vendor-specific model name identifier string.
STR entPhysicalName	1.3.6.1.2.1.47.1.1.1.1.7	SnmpAdminString	read-only	The textual name of the physical component.
I32 entPhysicalParentRelPos	1.3.6.1.2.1.47.1.1.1.1.6	Integer32	read-only	An indication of the relative position of this child component among all its sibling components.
STR entPhysicalSerialNum	1.3.6.1.2.1.47.1.1.1.1.11	SnmpAdminString	read-write	The vendor-specific serial number string for the physical component.
STR entPhysicalSoftwareRev	1.3.6.1.2.1.47.1.1.1.1.10	SnmpAdminString	read-only	The vendor-specific software revision string for the physical component.
entPhysicalTable	1.3.6.1.2.1.47.1.1.1		not-accessible	This table contains one row per physical component.
OCT entPhysicalUris	1.3.6.1.2.1.47.1.1.1.1.18	OCTET STRING	read-write	This object contains additional identification information.
OID entPhysicalVendorType	1.3.6.1.2.1.47.1.1.1.1.3	OBJECT IDENTIFIER	read-only	An indication of the vendor-specific hardware type of the physical component.

FAQ

What is ENTITY-MIB used for in a chassis-based router or switch monitoring setup?
It's the vendor-neutral IETF standard (RFC 6933) inventory model that represents a device's physical and logical components -- chassis, modules, power supplies, fans, sensors, ports -- as entries in entPhysicalTable, with fields like entPhysicalDescr, entPhysicalVendorType, entPhysicalContainedIn, and entPhysicalClass. It lets an operator enumerate every physical component in a chassis, confirm which slot a module sits in, and verify hardware, firmware (entPhysicalHardwareRev, entPhysicalFirmwareRev), and software revision levels are consistent across redundant components like fans, power supplies, or line cards.

Why do other hardware-monitoring MIBs reference ENTITY-MIB?
Because ENTITY-MIB's entPhysicalIndex is the common key many vendor-specific environment, power, and sensor MIBs use to associate their own readings with a specific physical component, making ENTITY-MIB a foundational dependency for hardware-health monitoring across virtually any modular router or switch.

RFC description

Physical entity MIB for managing hardware components, modules, and their relationships in networked devices (RFC 4133).

Start monitoring Modular/chassis-based router or switch (physical/logical entity inventory, vendor-neutral IETF standard RFC 6933) 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-MIB

What Is ENTITY-MIB?

Supported Devices

Monitoring Examples

What Can Be Monitored

This MIB depends on

Related MIBs

FAQ

RFC description