ENTITY-MIB

MIB Reference — IPNetwork Monitor

All MIBsENTITY-MIB

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.

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

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.

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

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.

OIDs
OID symbolicOID numericTypeAccessDescription
entityMIB1.3.6.1.2.1.47The Entity MIB (Version 3).
entityMIBObjects1.3.6.1.2.1.47.1
entityPhysical1.3.6.1.2.1.47.1.1
entPhysicalTable1.3.6.1.2.1.47.1.1.1not-accessibleThis table contains one row per physical component.
entPhysicalEntry1.3.6.1.2.1.47.1.1.1.1not-accessibleEntry for a physical component.
PHY entPhysicalIndex1.3.6.1.2.1.47.1.1.1.1.1PhysicalIndexread-onlyThe index for this entry.
STR entPhysicalDescr1.3.6.1.2.1.47.1.1.1.1.2SnmpAdminStringread-onlyA textual description of physical component.
OID entPhysicalVendorType1.3.6.1.2.1.47.1.1.1.1.3OBJECT IDENTIFIERread-onlyAn indication of the vendor-specific hardware type of the physical component.
PHY entPhysicalContainedIn1.3.6.1.2.1.47.1.1.1.1.4PhysicalIndexOrZeroread-onlyThe value of entPhysicalIndex for the physical entity which 'contains' this physical component.
PHY entPhysicalClass1.3.6.1.2.1.47.1.1.1.1.5PhysicalClassread-onlyAn indication of the general hardware type of the physical component.
I32 entPhysicalParentRelPos1.3.6.1.2.1.47.1.1.1.1.6Integer32read-onlyAn indication of the relative position of this child component among all its sibling components.
STR entPhysicalName1.3.6.1.2.1.47.1.1.1.1.7SnmpAdminStringread-onlyThe textual name of the physical component.
STR entPhysicalHardwareRev1.3.6.1.2.1.47.1.1.1.1.8SnmpAdminStringread-onlyThe vendor-specific hardware revision string for the physical component.
STR entPhysicalFirmwareRev1.3.6.1.2.1.47.1.1.1.1.9SnmpAdminStringread-onlyThe vendor-specific firmware revision string for the physical component.
STR entPhysicalSoftwareRev1.3.6.1.2.1.47.1.1.1.1.10SnmpAdminStringread-onlyThe vendor-specific software revision string for the physical component.
STR entPhysicalSerialNum1.3.6.1.2.1.47.1.1.1.1.11SnmpAdminStringread-writeThe vendor-specific serial number string for the physical component.
STR entPhysicalMfgName1.3.6.1.2.1.47.1.1.1.1.12SnmpAdminStringread-onlyThe name of the manufacturer of this physical component.
STR entPhysicalModelName1.3.6.1.2.1.47.1.1.1.1.13SnmpAdminStringread-onlyThe vendor-specific model name identifier string.
STR entPhysicalAlias1.3.6.1.2.1.47.1.1.1.1.14SnmpAdminStringread-writeThis object is an 'alias' name for the physical component.
STR entPhysicalAssetID1.3.6.1.2.1.47.1.1.1.1.15SnmpAdminStringread-writeThis object is a user-assigned asset tracking identifier.
T/F entPhysicalIsFRU1.3.6.1.2.1.47.1.1.1.1.16TruthValueread-onlyThis object indicates whether or not this physical component is considered a field replaceable unit (FRU).
DAT entPhysicalMfgDate1.3.6.1.2.1.47.1.1.1.1.17DateAndTimeread-onlyThis object contains the date of manufacturing of the managed component.
OCT entPhysicalUris1.3.6.1.2.1.47.1.1.1.1.18OCTET STRINGread-writeThis object contains additional identification information.
entityLogical1.3.6.1.2.1.47.1.2
entLogicalTable1.3.6.1.2.1.47.1.2.1not-accessibleThis table contains one row per logical entity.
entLogicalEntry1.3.6.1.2.1.47.1.2.1.1not-accessibleEntry for a logical entity.
I32 entLogicalIndex1.3.6.1.2.1.47.1.2.1.1.1Integer32read-onlyThe value of this object uniquely identifies the logical entity.
STR entLogicalDescr1.3.6.1.2.1.47.1.2.1.1.2SnmpAdminStringread-onlyA textual description of the logical entity.
OID entLogicalType1.3.6.1.2.1.47.1.2.1.1.3OBJECT IDENTIFIERread-onlyAn indication of the type of logical entity.
OCT entLogicalCommunity1.3.6.1.2.1.47.1.2.1.1.4OCTET STRINGread-onlyAn SNMPv1 or SNMPv2C community-string.
OCT entLogicalTAddress1.3.6.1.2.1.47.1.2.1.1.5OCTET STRINGread-onlyThe transport service address for this logical entity.
OID entLogicalTDomain1.3.6.1.2.1.47.1.2.1.1.6OBJECT IDENTIFIERread-onlyIndicates the kind of transport service.
OCT entLogicalContextEngineID1.3.6.1.2.1.47.1.2.1.1.7OCTET STRINGread-onlyThe authoritative SNMP engine identifier.
STR entLogicalContextName1.3.6.1.2.1.47.1.2.1.1.8SnmpAdminStringread-onlyThe SNMP context name.
entityMapping1.3.6.1.2.1.47.1.3
entityGeneral1.3.6.1.2.1.47.1.4
entityMIBConformance1.3.6.1.2.1.47.2
entityMIBCompliances1.3.6.1.2.1.47.2.1
entityMIBGroups1.3.6.1.2.1.47.2.2
entityPhysicalGroup1.3.6.1.2.1.47.2.2.1Physical entity objects.
entityLogicalGroup1.3.6.1.2.1.47.2.2.2Logical entity objects.
entityPhysical2Group1.3.6.1.2.1.47.2.2.3Additional physical entity objects.
entityPhysical3Group1.3.6.1.2.1.47.2.2.4Physical entity group v3.
entityLogical2Group1.3.6.1.2.1.47.2.2.5Logical entity group v2.
entityMappingGroup1.3.6.1.2.1.47.2.2.6Entity mapping objects.
entityGeneralGroup1.3.6.1.2.1.47.2.2.7General entity objects.

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.

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