RFC 2737
Entity MIB (Version 2)
Entity MIB (Version 2) 🦋
okay bestie, this is RFC 2737 and it's giving standards track 💅 It's an Internet standards track protocol document, so this is official, load-bearing stuff. Kenneth McCloghrie and Andy Bierman from Cisco Systems, Inc. wrote it in December 1999. It obsoletes RFC 2037 (the first Entity MIB), so it's basically the upgraded version, and it doesn't update any other RFCs. 🌸
Status of This Memo ✨
this doc is a standards track protocol for the Internet community, and it's literally asking for discussion and suggestions for improvements 🫶 For the current standardization state and status of this protocol, check the latest edition of the "Internet Official Protocol Standards" (STD 1). Distribution of this memo is unlimited, so share it with everyone 💜
Copyright Notice ✨
Copyright (C) The Internet Society (1999). All Rights Reserved. 🎀
Abstract ✨
this memo defines a chunk of the Management Information Base (MIB) for network management protocols in the Internet community 🧚 specifically, it describes managed objects for managing multiple logical and physical entities that are all managed by a single SNMP agent. one agent, many entities, iconic 👑
Table of Contents ✨
1 The SNMP Management Framework ............................... 2
2 Overview .................................................... 3
2.1 Terms ..................................................... 4
2.2 Relationship to Community Strings ......................... 5
2.3 Relationship to SNMP Contexts ............................. 5
2.4 Relationship to Proxy Mechanisms .......................... 6
2.5 Relationship to a Chassis MIB ............................. 6
2.6 Relationship to the Interfaces MIB ........................ 6
2.7 Relationship to the Other MIBs ............................ 7
2.8 Relationship to Naming Scopes ............................. 7
2.9 Multiple Instances of the Entity MIB ...................... 7
2.10 Re-Configuration of Entities ............................. 8
2.11 Textual Convention Change ................................ 8
2.12 MIB Structure ............................................ 8
2.12.1 entityPhysical Group ................................... 9
2.12.2 entityLogical Group .................................... 10
2.12.3 entityMapping Group .................................... 10
2.12.4 entityGeneral Group .................................... 11
2.12.5 entityNotifications Group .............................. 11
2.13 Multiple Agents .......................................... 11
2.14 Changes Since RFC 2037 ................................... 11
2.14.1 Textual Conventions .................................... 11
2.14.2 New entPhysicalTable Objects ........................... 12
2.14.3 New entLogicalTable Objects ............................ 12
2.14.4 Bugfixes ............................................... 12
3 Definitions ................................................. 13
4 Usage Examples .............................................. 38
4.1 Router/Bridge ............................................. 38
4.2 Repeaters ................................................. 44
5 Intellectual Property ....................................... 51
6 Acknowledgements ............................................ 51
7 References .................................................. 51
8 Security Considerations ..................................... 53
9 Authors' Addresses .......................................... 55
10 Full Copyright Statement ................................... 561. The SNMP Management Framework ✨
okay so the SNMP Management Framework is made of five major components 🔥
- an overall architecture, described in RFC 2571 [RFC2571].
- mechanisms for describing and naming objects and events for management purposes. The first version of this Structure of Management Information (SMI) is called SMIv1 and is described in STD 16, RFC 1155 [RFC1155], STD 16, RFC 1212 [RFC1212] and RFC 1215 [RFC1215]. The second version, called SMIv2, is described in STD 58, RFC 2578 [RFC2578], STD 58, RFC 2579 [RFC2579] and STD 58, RFC 2580 [RFC2580].
- message protocols for transferring management information. The first version of the SNMP message protocol is called SNMPv1 and is described in STD 15, RFC 1157 [RFC1157]. A second version, SNMPv2c, is not an Internet standards track protocol 🙈 It's described in RFC 1901 [RFC1901] and RFC 1906 [RFC1906]. The third version of the message protocol is called SNMPv3 and is described in RFC 1906 [RFC1906], RFC 2572 [RFC2572] and RFC 2574 [RFC2574].
- protocol operations for accessing management information. The first set of protocol operations and associated PDU formats is described in STD 15, RFC 1157 [RFC1157]. A second set of protocol operations and associated PDU formats is described in RFC 1905 [RFC1905].
- a set of fundamental applications described in RFC 2573 [RFC2573], plus the view-based access control mechanism described in RFC 2575 [RFC2575].
a more detailed intro to the current SNMP Management Framework is in RFC 2570 [RFC2570] 🦋
managed objects are accessed through a virtual information store called the Management Information Base or MIB. objects in the MIB are defined using the mechanisms defined in the SMI 💖
this memo specifies a MIB module that is compliant to the SMIv2. A MIB conforming to the SMIv1 can be produced through the appropriate translations. The resulting translated MIB must be semantically equivalent, except where objects or events are omitted because no translation is possible (use of Counter64). Some machine readable information in SMIv2 will be converted into textual descriptions in SMIv1 during the translation process. However, this loss of machine readable information is not considered to change the semantics of the MIB. so no panic, the vibes stay the same even when the format changes 🌈
2. Overview ✨
there's a real need for a standardized way to represent a single agent that supports multiple instances of one MIB 🍓 This is already true for at least 3 standard MIBs, and it's only going to become true for more and more MIBs as time goes on. For example:
- multiple instances of a bridge supported within a single device having a single agent;
- multiple repeaters supported by a single agent;
- multiple OSPF backbone areas, each one operating as part of its own Autonomous System, and each identified by the same area-id (e.g.,
0.0.0.0), supported inside a single router with one agent.
since it's one agent in each of these cases, there has to be some relationship binding all of these entities together 🔗 Basically there's some "overall" physical entity that houses everything that one agent manages. In other words, there are multiple "logical" entities inside a single physical entity. Sometimes the overall physical entity contains multiple (smaller) physical entities, and each logical entity is tied to a particular physical entity. Other times, the overall physical entity is a "compound" of multiple physical entities (like a stack of stackable hubs) 💅
what we need is a way to figure out exactly which logical entities are managed by the agent (with some version of SNMP), so we can actually talk to the agent about a specific logical entity 🫶 When different logical entities are associated with different physical entities inside the overall physical entity, it's also helpful to use that info to tell logical entities apart ✨
in these situations, varbinds for multiple logical entities don't need to be referenced in the same SNMP message (even though that might be useful someday). Instead, it's enough, and sometimes even better, to have the context/community in the message identify the logical entity the varbinds apply to 🧚
version 2 of this MIB handles new requirements that showed up after the first Entity MIB (RFC 2037 [RFC2037]) was published 😭 There's a need for a standardized way to provide non-volatile, administratively assigned identifiers for physical components represented in the Entity MIB. There's also a need to line the Entity MIB up with the SNMPv3 administrative framework (RFC 2571 [RFC2571]). Implementation experience has shown that extra physical component attributes are also desirable 🌸
2.1. Terms
some new terms are used throughout this document, so here's the tea ☕
- Naming Scope A "naming scope" represents the set of information that may be potentially accessed through a single SNMP operation. All instances within the naming scope share the same unique identifier space. For SNMPv1, a naming scope is identified by the value of the associated
entLogicalCommunityinstance. For SNMPv3, the termcontextis used instead of "naming scope". The complete definition of an SNMP context can be found in section 3.3.1 of RFC 2571 [RFC2571]. - Multi-Scoped Object A MIB object for which identical instance values identify different managed information in different naming scopes is called a "multi-scoped" MIB object. 🎀
- Single-Scoped Object A MIB object for which identical instance values identify the same managed information in different naming scopes is called a "single-scoped" MIB object. 🎀
- Logical Entity A managed system contains one or more logical entities, each represented by at most one instantiation of each of a particular set of MIB objects. A set of management functions is associated with each logical entity. Examples of logical entities include routers, bridges, print-servers, etc. 👑
- Physical Entity A "physical entity" or "physical component" represents an identifiable physical resource within a managed system. Zero or more logical entities may utilize a physical resource at any given time. It is an implementation-specific matter which physical components are represented by an agent in the
entPhysicalTable. Typically, physical resources (e.g., communications ports, backplanes, sensors, daughter-cards, power supplies, the overall chassis) which can be managed via functions associated with one or more logical entities are included in the MIB. 🔥 - Containment Tree Each physical component may be modeled as "contained" within another physical component. A "containment-tree" is the conceptual sequence of
entPhysicalIndexvalues which uniquely specifies the exact physical location of a physical component within the managed system. It is generated by "following and recording" eachentPhysicalContainedIninstance "up the tree towards the root", until a value of zero indicating no further containment is found. 🌈
2.2. Relationship to Community Strings 🎀
Okay so for community-based SNMP, telling different logical entities apart is one job of the community string (STD 15, RFC 1157 [RFC1157]), but it's not the only job 💅 That's why every community string gets represented as its own logical entity ✨
Different logical entities can share the same naming scope (and therefore the same values of entLogicalCommunity) 🦋 This is totally fine, as long as they don't need the same instance of a MIB object to represent different managed information.
2.3. Relationship to SNMP Contexts 🧚
Version 2 of the Entity MIB supports attaching SNMPv3 contexts to logical entities 💜 Two new MIB objects, an SnmpEngineID and ContextName pair, work together to identify an SNMP context linked to a logical entity. Then that context can be used (together with entLogicalTAddress and entLogicalTDomain) to send SNMPv3 messages on behalf of a particular logical entity 🔥
2.4. Relationship to Proxy Mechanisms 🌸
The Entity MIB is built for functional component discovery 🔍 The administrative relationships between logical entities are not visible in any Entity MIB tables, so an NMS can't tell whether MIB instances in different naming scopes are realized locally or remotely (e.g., via some proxy mechanism) just by looking at the Entity MIB objects 🙈
Managing administrative framework functions isn't an explicit goal of the Entity MIB WG right now. This new area might get revisited once there's some operational experience with the Entity MIB 🍓
Quick note: for community-based versions of SNMP, a network administrator will likely be able to link community strings with naming scopes using proprietary mechanisms, as a matter of configuration. There are no mechanisms for managing naming scopes defined in this MIB.
2.5. Relationship to a Chassis MIB 🌈
Some of you might remember that a previous IETF working group tried to define a Chassis MIB 🥲 No consensus was reached, possibly because its scope was too broad. So this MIB is not meant to be a "Chassis MIB replacement", and it's not in scope for it to hold everything that might be needed to manage a "chassis" ✨ That said, the entities represented by an implementation of this MIB might very well be contained in a chassis 💖
2.6. Relationship to the Interfaces MIB 🦋
The Entity MIB has a mapping table that identifies physical components with 'external values' (e.g., ifIndex) inside a given naming scope ⭐ This table can be used to find the physical location of each interface in the ifTable (RFC 2233 [RFC2233]). Since ifIndex values in different contexts aren't related to one another, the interface-to-physical-component associations are relative to the same logical entity within the agent 🫶
The Entity MIB also has entPhysicalName and entPhysicalAlias objects. These approximate the semantics of the ifName and ifAlias objects (respectively) from the Interfaces MIB [RFC2233], but for all types of physical components 💅
2.7. Relationship to the Other MIBs 🧚
The Entity MIB has a mapping table that identifies physical components which have identifiers from other standard MIBs associated with them 🍓 For example, this table can be used along with the physical mapping table to find the physical location of each repeater port in the rptrPortTable, or each interface in the ifTable 👑
2.8. Relationship to Naming Scopes 💀
There's some question about which MIB objects can be returned within a given naming scope 👀 MIB objects that aren't multi-scoped within a managed system will likely ignore context information in implementation. In that case, those objects will probably be returned in all naming scopes (e.g., not just the 'default' naming scope or the SNMPv3 default context) 🌸
For example, a community string used to access the management information for logical device 'bridge2' may allow access to all the non-bridge related objects in the 'default' naming scope, plus a second instance of the Bridge MIB (RFC 1493 [RFC1493]) 💜
How single-scoped MIB objects get isolated by the agent is an implementation-specific matter 🔧 An agent may want to limit the objects returned in a particular naming scope to just the multi-scoped objects in that scope (e.g., system group and the Bridge MIB). In that case, all single-scoped management information would belong to a common naming scope (e.g., 'default'), which itself may contain some multi-scoped objects (e.g., system group) 🎀
2.9. Multiple Instances of the Entity MIB 👯
It's possible for more than one agent to exist in a managed system, and then multiple instances of the Entity MIB (representing the same managed objects) may be available to an NMS 🫧
To keep agent implementation complexity down, multiple instances of the Entity MIB are not required to be equivalent or even consistent 🙃 An NMS may be able to 'align' instances returned by different agents by examining the columns of each table, but vendor-specific identifiers and (especially) index values are likely to differ. Each agent may also be managing different subsets of the entire chassis 🧩
When a physically-modular device is represented entirely by a single agent, the entry whose entPhysicalContainedIn has the value zero would likely have 'chassis' as the value of its entPhysicalClass 🏗️ Alternatively, for an agent on a module where it represents only the physical entities on that module (not those on other modules), the entry whose entPhysicalContainedIn has the value zero would likely have 'module' as the value of its entPhysicalClass 🌟
An agent implementation of the entLogicalTable is not required to contain information about logical entities managed primarily by other agents. In other words, the entLogicalTAddress and entLogicalTDomain objects in the entLogicalTable are there to support a historical multiplexing mechanism, not to identify other SNMP agents 🕰️
Note that the Entity MIB is a single-scoped MIB, in the event that an agent represents the MIB in different naming scopes 🧐
2.10. Re-Configuration of Entities ⚙️
Most of the MIB objects defined in this MIB have at most a read-only MAX-ACCESS clause 🔒 This was a conscious decision by the working group to keep this MIB's scope limited. The second version of the Entity MIB lets a network administrator configure some common attributes of physical components ✏️
2.11. Textual Convention Change 📝
Version 1 of the Entity MIB has three MIB objects defined with the (now obsolete) DisplayString textual convention 🥀 In version 2, the syntax for these objects has been updated to use the (now preferred) SnmpAdminString textual convention 🌷
The working group knows this change isn't strictly supported by SMIv2 😬 In its judgment, deprecating the old objects and defining new ones would have a more adverse impact on backward compatibility and interoperability, given the particular semantics of these objects 🫶
2.12. MIB Structure 🏛️
The Entity MIB has five groups of MIB objects 🎀
- entityPhysical group: describes the physical entities managed by a single agent.
- entityLogical group: describes the logical entities managed by a single agent.
- entityMapping group: describes the associations between the physical entities, logical entities, interfaces, and non-interface ports managed by a single agent.
- entityGeneral group: describes general system attributes shared by potentially all types of entities managed by a single agent.
- entityNotifications group: contains status indication notifications.
2.12.1. entityPhysical Group 🔩
This group has a single table for identifying physical system components, called the entPhysicalTable 📋
The entPhysicalTable has one row per physical entity, and it must always contain at least one row for an "overall" physical entity 🌟 That row should have an entPhysicalClass value of stack(11), chassis(3) or module(9) 🏗️
Each row is indexed by an arbitrary, small integer, and it holds a description and type of the physical entity 🧸 It can also optionally hold the index number of another entPhysicalEntry, which shows a containment relationship between the two 🪆
Version 2 of the Entity MIB adds more MIB objects for each physical entity ✨ Some common read-only attributes were added, plus three writable string objects 💅
- entPhysicalAlias This string can be used by an NMS as a non-volatile identifier for the physical component. Keeping a non-volatile string for every physical component in the entPhysicalTable can be costly and unnecessary 💸 An agent may algorithmically generate 'entPhysicalAlias' strings for particular entries (e.g., based on the entPhysicalClass value) 🤖
- entPhysicalAssetID This string stores a user-specific asset identifier for removable physical components 🏷️ To keep the non-volatile storage needed by an agent down, a network administrator should only assign asset identifiers to physical entities that are field-replaceable (i.e., not permanently contained within another physical entity) 🔁
- entPhysicalSerialNum This string stores a vendor-specific serial number for physical components 🔢 It's writable in case an agent can't identify the serial numbers of all installed physical entities, and a network administrator wants to configure the non-volatile serial number strings manually (via an NMS application) 🖊️
2.12.2. entityLogical Group 🦋
This group has a single table for identifying logical entities, called the entLogicalTable 🗂️
The entLogicalTable has one row per logical entity 💖 Each row is indexed by an arbitrary, small integer, and holds a name, description, and type of the logical entity. It also has information that allows access to the MIB information for the logical entity 🔑 This covers SNMP versions that use a community name (with some form of implied context representation), and SNMP versions that use the SNMP ARCH [RFC2571] method of context identification 🧠
If a agent represents multiple logical entities with this MIB, then this group must be implemented for all logical entities known to the agent 🙌
If an agent represents a single logical entity, or multiple logical entities within a single naming scope, then the agent may omit implementing this group 🫠
2.12.3. entityMapping Group ✨
okay this group is giving relationships 🔗 and it has three tables that show how different parts of the system connect to each other, bestie 💖
The entLPMappingTable maps entLogicalIndex values (the logical entities) to entPhysicalIndex values (the physical components that support them) 🧚. One logical entity can be backed by more than one physical component, and more than one logical entity can share the same physical component, so it's a whole web of connections 🕸️. If an agent only represents a single logical entity, or several logical entities inside one naming scope, the agent is allowed to leave this table out entirely 🌸.
The entAliasMappingTable maps pairs of entLogicalIndex and entPhysicalIndex to 'alias' object identifier values 🦋. This is the table that lets resources managed by other MIBs, like repeater ports, bridge ports, and physical and logical interfaces, show up inside the physical entity hierarchy. Each alias identifier only means something inside one particular naming scope, so keep that in mind 👀. Same deal as before: if the agent represents a single logical entity, or multiple logical entities within a single naming scope, it can skip implementing this table 💅.
The entPhysicalContainsTable is the simple one 🍓. It holds mappings between 'entPhysicalContainedIn' values for every container and 'containee' pair in the managed system. Because of how this table is indexed, an NMS can quickly find the entPhysicalIndex values for all the children of a given physical entity. Main character indexing ✨.
2.12.4. entityGeneral Group 🌈
This group is the general info drawer 🗄️, holding details that relate to the other object groups.
Right now the entGeneral group has just one scalar object, entLastChangeTime. It stores the value of sysUptime at the moment any part of the Entity MIB configuration last changed ⏰. Very useful, very lowkey 🫶.
2.12.5. entityNotifications Group 🔔
This group holds the notification definitions for the overall status of the Entity MIB instantiation. Ring ring 📣.
2.13. Multiple Agents 🤝
Okay so the big reason for this MIB is to represent the multiple logical entities one agent supports 🧠, BUT it can also represent multiple logical entities supported by multiple agents, as long as they all live in the same "overall" physical entity 🧩. Honestly the SNMP architecture kind of assumes this already, since a network management station doesn't really need to know how many agents there are 🙈.
Now the tea ☕: there is no agreement yet on how much cooperation agent implementations should be expected to have. So multiple agents within the same managed system are free to implement the Entity MIB independently 🦋. (Go check out the section on "Multiple Instances of the Entity MIB" for more details, it's a whole vibe 💜.)
2.14. Changes Since RFC 2037 📝
2.14.1. Textual Conventions
The PhysicalClass TC text got clarified, and there's a new enumeration to support 'stackable' components 🥞. The SnmpEngineIdOrNone TC was added to support SNMPv3 🔐.
2.14.2. New entPhysicalTable Objects
The entPhysicalHardwareRev, entPhysicalFirmwareRev, and entPhysicalSoftwareRev objects were added for revision identification 🔖.
The entPhysicalSerialNum, entPhysicalMfgName, entPhysicalModelName, and entPhysicalIsFru objects were added for better vendor identification of physical components 🏷️. Also, a management station can set entPhysicalSerialNum in case the agent can't figure that info out on its own 🫶.
The entPhysicalAlias and entPhysicalAssetID objects were added for better user component identification 💅. They're meant to be set by a management station, and the agent should keep them across restarts 💖.
2.14.3. New entLogicalTable Objects
The entLogicalContextEngineID and entLogicalContextName objects were added to provide an SNMP context for SNMPv3 access on behalf of a logical entity 🧚.
2.14.4. Bugfixes 🐛
Yay, a bug in the entLogicalCommunity object got fixed 🎉. The subrange was wrong (1..255) and is now (0..255). The description clause got clarified too. This object is now deprecated 🥀.
The entLastChangeTime object description was changed so it generalizes the events that update the last change timestamp ⏰.
The syntax changed from DisplayString to SnmpAdminString for the entPhysicalDescr, entPhysicalName, and entLogicalDescr objects 🌷.
3. Definitions 📜
ENTITY-MIB DEFINITIONS ::= BEGIN
IMPORTS
MODULE-IDENTITY, OBJECT-TYPE, mib-2, NOTIFICATION-TYPE
FROM SNMPv2-SMI
TDomain, TAddress, TEXTUAL-CONVENTION,
AutonomousType, RowPointer, TimeStamp, TruthValue
FROM SNMPv2-TC
MODULE-COMPLIANCE, OBJECT-GROUP, NOTIFICATION-GROUP
FROM SNMPv2-CONF
SnmpAdminString
FROM SNMP-FRAMEWORK-MIB;
entityMIB MODULE-IDENTITY
LAST-UPDATED "9912070000Z" -- December 7, 1999
ORGANIZATION "IETF ENTMIB Working Group"
CONTACT-INFO
" WG E-mail: entmib@cisco.com
Subscribe: majordomo@cisco.com
msg body: subscribe entmib
Keith McCloghrie
ENTMIB Working Group Chair
Cisco Systems Inc.
170 West Tasman Drive
San Jose, CA 95134
+1 408-526-5260
kzm@cisco.com
Andy Bierman
ENTMIB Working Group Editor
Cisco Systems Inc.
170 West Tasman Drive
San Jose, CA 95134
+1 408-527-3711
abierman@cisco.com"
DESCRIPTION
"The MIB module for representing multiple logical
entities supported by a single SNMP agent."
REVISION "9912070000Z"
DESCRIPTION
"Initial Version of Entity MIB (Version 2).
This revision obsoletes RFC 2037.
This version published as RFC 2737."
REVISION "9610310000Z"
DESCRIPTION
"Initial version (version 1), published as
RFC 2037."
::= { mib-2 47 }
entityMIBObjects OBJECT IDENTIFIER ::= { entityMIB 1 }
-- MIB contains four groups
entityPhysical OBJECT IDENTIFIER ::= { entityMIBObjects 1 }
entityLogical OBJECT IDENTIFIER ::= { entityMIBObjects 2 }
entityMapping OBJECT IDENTIFIER ::= { entityMIBObjects 3 }
entityGeneral OBJECT IDENTIFIER ::= { entityMIBObjects 4 }
-- Textual Conventions
PhysicalIndex ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"An arbitrary value which uniquely identifies the physical
entity. The value should be a small positive integer; index
values for different physical entities are not necessarily
contiguous."
SYNTAX INTEGER (1..2147483647)
PhysicalClass ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"An enumerated value which provides an indication of the
general hardware type of a particular physical entity.
There are no restrictions as to the number of
entPhysicalEntries of each entPhysicalClass, which must be
instantiated by an agent.
The enumeration 'other' is applicable if the physical entity
class is known, but does not match any of the supported
values.
The enumeration 'unknown' is applicable if the physical
entity class is unknown to the agent.
The enumeration 'chassis' is applicable if the physical
entity class is an overall container for networking
equipment. Any class of physical entity except a stack may
be contained within a chassis, and a chassis may only be
contained within a stack.
The enumeration 'backplane' is applicable if the physical
entity class is some sort of device for aggregating and
forwarding networking traffic, such as a shared backplane in
a modular ethernet switch. Note that an agent may model a
backplane as a single physical entity, which is actually
implemented as multiple discrete physical components (within
a chassis or stack).
The enumeration 'container' is applicable if the physical
entity class is capable of containing one or more removable
physical entities, possibly of different types. For example,
each (empty or full) slot in a chassis will be modeled as a
container. Note that all removable physical entities should
be modeled within a container entity, such as field-
replaceable modules, fans, or power supplies. Note that all
known containers should be modeled by the agent, including
empty containers.
The enumeration 'powerSupply' is applicable if the physical
entity class is a power-supplying component.
The enumeration 'fan' is applicable if the physical entity
class is a fan or other heat-reduction component.
The enumeration 'sensor' is applicable if the physical
entity class is some sort of sensor, such as a temperature
sensor within a router chassis.
The enumeration 'module' is applicable if the physical
entity class is some sort of self-contained sub-system. If
it is removable, then it should be modeled within a
container entity, otherwise it should be modeled directly
within another physical entity (e.g., a chassis or another
module).
The enumeration 'port' is applicable if the physical entity
class is some sort of networking port, capable of receiving
and/or transmitting networking traffic.
The enumeration 'stack' is applicable if the physical entity
class is some sort of super-container (possibly virtual),
intended to group together multiple chassis entities. A
stack may be realized by a 'virtual' cable, a real
interconnect cable, attached to multiple chassis, or may in
fact be comprised of multiple interconnect cables. A stack
should not be modeled within any other physical entities,
but a stack may be contained within another stack. Only
chassis entities should be contained within a stack."
SYNTAX INTEGER {
other(1),
unknown(2),
chassis(3),
backplane(4),
container(5), -- e.g., chassis slot or daughter-card holder
powerSupply(6),
fan(7),
sensor(8),
module(9), -- e.g., plug-in card or daughter-card
port(10),
stack(11) -- e.g., stack of multiple chassis entities
}
SnmpEngineIdOrNone ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"A specially formatted SnmpEngineID string for use with the
Entity MIB.
If an instance of an object of SYNTAX SnmpEngineIdOrNone has
a non-zero length, then the object encoding and semantics
are defined by the SnmpEngineID textual convention (see RFC
2571 [RFC2571]).
If an instance of an object of SYNTAX SnmpEngineIdOrNone
contains a zero-length string, then no appropriate
SnmpEngineID is associated with the logical entity (i.e.,
SNMPv3 not supported)."
SYNTAX OCTET STRING (SIZE(0..32)) -- empty string or SnmpEngineID
-- The Physical Entity Tableokay bestie, this is the main event 💖 The table is where every physical thing gets its own row, and the whole thing is built on a clean parent and child family tree 🌳✨
entPhysicalTable OBJECT-TYPE
SYNTAX SEQUENCE OF EntPhysicalEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"This table contains one row per physical entity. There is
always at least one row for an 'overall' physical entity."
::= { entityPhysical 1 }so the table is one row per physical entity, and there's always at least one row for the 'overall' one 🎀 that 'overall' row is literally the top of the whole family tree, iconic 👑
entPhysicalEntry OBJECT-TYPE
SYNTAX EntPhysicalEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"Information about a particular physical entity.
Each entry provides objects (entPhysicalDescr,
entPhysicalVendorType, and entPhysicalClass) to help an NMS
identify and characterize the entry, and objects
(entPhysicalContainedIn and entPhysicalParentRelPos) to help
an NMS relate the particular entry to other entries in this
table."
INDEX { entPhysicalIndex }
::= { entPhysicalTable 1 }each row is one particular physical entity 🦋 the row is keyed by entPhysicalIndex, so that's how you find it 🔍 the descr, vendor type and class columns help an NMS figure out what the thing even is, and the containedIn and parentRelPos columns help it place the thing in the family tree 🧚
EntPhysicalEntry ::= SEQUENCE {
entPhysicalIndex PhysicalIndex,
entPhysicalDescr SnmpAdminString,
entPhysicalVendorType AutonomousType,
entPhysicalContainedIn INTEGER,
entPhysicalClass PhysicalClass,
entPhysicalParentRelPos INTEGER,
entPhysicalName SnmpAdminString,
entPhysicalHardwareRev SnmpAdminString,
entPhysicalFirmwareRev SnmpAdminString,
entPhysicalSoftwareRev SnmpAdminString,
entPhysicalSerialNum SnmpAdminString,
entPhysicalMfgName SnmpAdminString,
entPhysicalModelName SnmpAdminString,
entPhysicalAlias SnmpAdminString,
entPhysicalAssetID SnmpAdminString,
entPhysicalIsFRU TruthValue
}this SEQUENCE is the whole row's wardrobe, every column in one outfit 👗💅 sixteen columns total, and each one has its own type, so no mix-ups 🌸
entPhysicalIndex OBJECT-TYPE
SYNTAX PhysicalIndex
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The index for this entry."
::= { entPhysicalEntry 1 }entPhysicalIndex is the index, and it's not-accessible, so it's more of a behind-the-scenes key than something you read directly 🔑
entPhysicalDescr OBJECT-TYPE
SYNTAX SnmpAdminString
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"A textual description of physical entity. This object
should contain a string which identifies the manufacturer's
name for the physical entity, and should be set to a
distinct value for each version or model of the physical
entity. "
::= { entPhysicalEntry 2 }the descr is a text description of the physical entity, and it's read-only so you look but don't touch 👀 it should carry the manufacturer's name and get its own distinct value for each version or model, so no two siblings are confusing 💜
entPhysicalVendorType OBJECT-TYPE
SYNTAX AutonomousType
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"An indication of the vendor-specific hardware type of the
physical entity. Note that this is different from the
definition of MIB-II's sysObjectID.
An agent should set this object to a enterprise-specific
registration identifier value indicating the specific
equipment type in detail. The associated instance of
entPhysicalClass is used to indicate the general type of
hardware device.
If no vendor-specific registration identifier exists for
this physical entity, or the value is unknown by this agent,
then the value { 0 0 } is returned."
::= { entPhysicalEntry 3 }vendor type is the vendor-specific hardware type, and it is NOT the same thing as MIB-II's sysObjectID, so don't mix those up bestie 🙈 an agent should set this to an enterprise-specific registration identifier for the exact equipment type, and the class column covers the general type 🎀 if there's no vendor registration identifier, or the agent doesn't know the value, it comes back as { 0 0 } 💀
entPhysicalContainedIn OBJECT-TYPE
SYNTAX INTEGER (0..2147483647)
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The value of entPhysicalIndex for the physical entity which
'contains' this physical entity. A value of zero indicates
this physical entity is not contained in any other physical
entity. Note that the set of 'containment' relationships
define a strict hierarchy; that is, recursion is not
allowed.
In the event a physical entity is contained by more than one
physical entity (e.g., double-wide modules), this object
should identify the containing entity with the lowest value
of entPhysicalIndex."
::= { entPhysicalEntry 4 }containedIn is literally the index of whatever is holding this entity, so it's the 'who's your mom' column 🫶 zero means nobody is containing it, and containment is a strict hierarchy, so no recursion loops allowed 🌀 if something is double-wide and sits inside more than one container, this should point at the container with the lowest entPhysicalIndex 🧩
entPhysicalClass OBJECT-TYPE
SYNTAX PhysicalClass
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"An indication of the general hardware type of the physical
entity.
An agent should set this object to the standard enumeration
value which most accurately indicates the general class of
the physical entity, or the primary class if there is more
than one.
If no appropriate standard registration identifier exists
for this physical entity, then the value 'other(1)' is
returned. If the value is unknown by this agent, then the
value 'unknown(2)' is returned."
::= { entPhysicalEntry 5 }class is the general hardware type, like the big category bucket 🪣 an agent should pick the standard enumeration value that best matches, or the primary class if there's more than one 💅 no fitting standard identifier means 'other(1)', and a value the agent can't figure out means 'unknown(2)' 🤷♀️
entPhysicalParentRelPos OBJECT-TYPE
SYNTAX INTEGER (-1..2147483647)
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"An indication of the relative position of this 'child'
component among all its 'sibling' components. Sibling
components are defined as entPhysicalEntries which share the
same instance values of each of the entPhysicalContainedIn
and entPhysicalClass objects.
An NMS can use this object to identify the relative ordering
for all sibling components of a particular parent
(identified by the entPhysicalContainedIn instance in each
sibling entry).
This value should match any external labeling of the
physical component if possible. For example, for a container
(e.g., card slot) labeled as 'slot #3',
entPhysicalParentRelPos should have the value '3'. Note
that the entPhysicalEntry for the module plugged in slot 3
should have an entPhysicalParentRelPos value of '1'.
If the physical position of this component does not match
any external numbering or clearly visible ordering, then
user documentation or other external reference material
should be used to determine the parent-relative position. If
this is not possible, then the the agent should assign a
consistent (but possibly arbitrary) ordering to a given set
of 'sibling' components, perhaps based on internal
representation of the components.
If the agent cannot determine the parent-relative position
for some reason, or if the associated value of
entPhysicalContainedIn is '0', then the value '-1' is
returned. Otherwise a non-negative integer is returned,
indicating the parent-relative position of this physical
entity.
Parent-relative ordering normally starts from '1' and
continues to 'N', where 'N' represents the highest
positioned child entity. However, if the physical entities
(e.g., slots) are labeled from a starting position of zero,
then the first sibling should be associated with a
entPhysicalParentRelPos value of '0'. Note that this
ordering may be sparse or dense, depending on agent
implementation.
The actual values returned are not globally meaningful, as
each 'parent' component may use different numbering
algorithms. The ordering is only meaningful among siblings
of the same parent component.
The agent should retain parent-relative position values
across reboots, either through algorithmic assignment or use
of non-volatile storage."
::= { entPhysicalEntry 6 }parentRelPos is the sibling ordering column, and it gets a whole essay because it's a big deal 🌈✨
siblings are entries that share the same containedIn AND the same class, so they're the 'same family, same type' crew 👯♀️ ideally the number matches whatever label is printed on the hardware, so slot #3 gets a 3, and the module plugged into it gets a 1 🎯 if the label doesn't help, the docs can, and if even that fails the agent just invents a consistent (maybe random) order 🎲 no clue at all, or the containedIn is 0? that's a -1, otherwise you get a non-negative integer 💀
ordering usually starts at 1 and counts up to N, but if the slots are labeled from zero, the first sibling is a 0 🍓 gaps are allowed too, so it can be sparse or dense 🌸 and the numbers only mean something among siblings with the same parent, because each parent can count however it likes 💜 the agent should keep these numbers across reboots, either by algorithm or by saving them in non-volatile storage, no forgetting the slot order after a restart 🔥
Okay bestie, the physical entity details keep coming and they are SO good 💖 Here's the next chunk of the MIB definitions 🎀
entPhysicalName OBJECT-TYPE
SYNTAX SnmpAdminString
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The textual name of the physical entity. The value of this
object should be the name of the component as assigned by
the local device and should be suitable for use in commands
entered at the device's `console'. This might be a text
name, such as `console' or a simple component number (e.g.,
port or module number), such as `1', depending on the
physical component naming syntax of the device.
If there is no local name, or this object is otherwise not
applicable, then this object contains a zero-length string.
Note that the value of entPhysicalName for two physical
entities will be the same in the event that the console
interface does not distinguish between them, e.g., slot-1
and the card in slot-1."
::= { entPhysicalEntry 7 }
entPhysicalHardwareRev OBJECT-TYPE
SYNTAX SnmpAdminString
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The vendor-specific hardware revision string for the
physical entity. The preferred value is the hardware
revision identifier actually printed on the component itself
(if present).
Note that if revision information is stored internally in a
non-printable (e.g., binary) format, then the agent must
convert such information to a printable format, in an
implementation-specific manner.
If no specific hardware revision string is associated with
the physical component, or this information is unknown to
the agent, then this object will contain a zero-length
string."
::= { entPhysicalEntry 8 }
entPhysicalFirmwareRev OBJECT-TYPE
SYNTAX SnmpAdminString
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The vendor-specific firmware revision string for the
physical entity.
Note that if revision information is stored internally in a
non-printable (e.g., binary) format, then the agent must
convert such information to a printable format, in an
implementation-specific manner.
If no specific firmware programs are associated with the
physical component, or this information is unknown to the
agent, then this object will contain a zero-length string."
::= { entPhysicalEntry 9 }
entPhysicalSoftwareRev OBJECT-TYPE
SYNTAX SnmpAdminString
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The vendor-specific software revision string for the
physical entity.
Note that if revision information is stored internally in a
non-printable (e.g., binary) format, then the agent must
convert such information to a printable format, in an
implementation-specific manner.
If no specific software programs are associated with the
physical component, or this information is unknown to the
agent, then this object will contain a zero-length string."
::= { entPhysicalEntry 10 }
entPhysicalSerialNum OBJECT-TYPE
SYNTAX SnmpAdminString (SIZE (0..32))
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The vendor-specific serial number string for the physical
entity. The preferred value is the serial number string
actually printed on the component itself (if present).
On the first instantiation of an physical entity, the value
of entPhysicalSerialNum associated with that entity is set
to the correct vendor-assigned serial number, if this
information is available to the agent. If a serial number
is unknown or non-existent, the entPhysicalSerialNum will be
set to a zero-length string instead.
Note that implementations which can correctly identify the
serial numbers of all installed physical entities do not
need to provide write access to the entPhysicalSerialNum
object. Agents which cannot provide non-volatile storage for
the entPhysicalSerialNum strings are not required to
implement write access for this object.
Not every physical component will have a serial number, or
even need one. Physical entities for which the associated
value of the entPhysicalIsFRU object is equal to 'false(2)'
(e.g., the repeater ports within a repeater module), do not
need their own unique serial number. An agent does not have
to provide write access for such entities, and may return a
zero-length string.
If write access is implemented for an instance of
entPhysicalSerialNum, and a value is written into the
instance, the agent must retain the supplied value in the
entPhysicalSerialNum instance associated with the same
physical entity for as long as that entity remains
instantiated. This includes instantiations across all re-
initializations/reboots of the network management system,
including those which result in a change of the physical
entity's entPhysicalIndex value."
::= { entPhysicalEntry 11 }
entPhysicalMfgName OBJECT-TYPE
SYNTAX SnmpAdminString
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The name of the manufacturer of this physical component.
The preferred value is the manufacturer name string actually
printed on the component itself (if present).
Note that comparisons between instances of the
entPhysicalModelName, entPhysicalFirmwareRev,
entPhysicalSoftwareRev, and the entPhysicalSerialNum
objects, are only meaningful amongst entPhysicalEntries with
the same value of entPhysicalMfgName.
If the manufacturer name string associated with the physical
component is unknown to the agent, then this object will
contain a zero-length string."
::= { entPhysicalEntry 12 }
entPhysicalModelName OBJECT-TYPE
SYNTAX SnmpAdminString
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The vendor-specific model name identifier string associated
with this physical component. The preferred value is the
customer-visible part number, which may be printed on the
component itself.
If the model name string associated with the physical
component is unknown to the agent, then this object will
contain a zero-length string."
::= { entPhysicalEntry 13 }
entPhysicalAlias OBJECT-TYPE
SYNTAX SnmpAdminString (SIZE (0..32))
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"This object is an 'alias' name for the physical entity as
specified by a network manager, and provides a non-volatile
'handle' for the physical entity.
On the first instantiation of an physical entity, the value
of entPhysicalAlias associated with that entity is set to
the zero-length string. However, agent may set the value to
a locally unique default value, instead of a zero-length
string.
If write access is implemented for an instance of
entPhysicalAlias, and a value is written into the instance,
the agent must retain the supplied value in the
entPhysicalAlias instance associated with the same physical
entity for as long as that entity remains instantiated.
This includes instantiations across all re-
initializations/reboots of the network management system,
including those which result in a change of the physical
entity's entPhysicalIndex value."
::= { entPhysicalEntry 14 }
entPhysicalAssetID OBJECT-TYPE
SYNTAX SnmpAdminString (SIZE (0..32))
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"This object is a user-assigned asset tracking identifier
for the physical entity as specified by a network manager,
and provides non-volatile storage of this information.
On the first instantiation of an physical entity, the value
of entPhysicalAssetID associated with that entity is set to
the zero-length string.
Not every physical component will have a asset tracking
identifier, or even need one. Physical entities for which
the associated value of the entPhysicalIsFRU object is equal
to 'false(2)' (e.g., the repeater ports within a repeater
module), do not need their own unique asset tracking
identifier. An agent does not have to provide write access
for such entities, and may instead return a zero-length
string.
If write access is implemented for an instance of
entPhysicalAssetID, and a value is written into the
instance, the agent must retain the supplied value in the
entPhysicalAssetID instance associated with the same
physical entity for as long as that entity remains
instantiated. This includes instantiations across all re-
initializations/reboots of the network management system,
including those which result in a change of the physical
entity's entPhysicalIndex value.
If no asset tracking information is associated with the
physical component, then this object will contain a zero-
length string."
::= { entPhysicalEntry 15 }
entPhysicalIsFRU OBJECT-TYPE
SYNTAX TruthValue
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"This object indicates whether or not this physical entity
is considered a 'field replaceable unit' by the vendor. If
this object contains the value 'true(1)' then this
entPhysicalEntry identifies a field replaceable unit. For
all entPhysicalEntries which represent components that are
permanently contained within a field replaceable unit, the
value 'false(2)' should be returned for this object."
::= { entPhysicalEntry 16 }
-- The Logical Entity Table
entLogicalTable OBJECT-TYPE
SYNTAX SEQUENCE OF EntLogicalEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"This table contains one row per logical entity. For agents
which implement more than one naming scope, at least one
entry must exist. Agents which instantiate all MIB objects
within a single naming scope are not required to implement
this table."
::= { entityLogical 1 }
entLogicalEntry OBJECT-TYPE
SYNTAX EntLogicalEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"Information about a particular logical entity. Entities
may be managed by this agent or other SNMP agents (possibly)
in the same chassis."
INDEX { entLogicalIndex }
::= { entLogicalTable 1 }EntLogicalEntry is the row layout for the entLogicalTable we just met, so every column of that table lives right here 🎀
EntLogicalEntry ::= SEQUENCE {
entLogicalIndex INTEGER,
entLogicalDescr SnmpAdminString,
entLogicalType AutonomousType,
entLogicalCommunity OCTET STRING,
entLogicalTAddress TAddress,
entLogicalTDomain TDomain,
entLogicalContextEngineID SnmpEngineIdOrNone,
entLogicalContextName SnmpAdminString
}
entLogicalIndex OBJECT-TYPE
SYNTAX INTEGER (1..2147483647)
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The value of this object uniquely identifies the logical
entity. The value should be a small positive integer; index
values for different logical entities are are not
necessarily contiguous."
::= { entLogicalEntry 1 }okay so the index is the key that tells each logical entity apart 🔑 it's a small positive integer and the values don't have to be back-to-back, so gaps are totally allowed bestie 🌸
entLogicalDescr OBJECT-TYPE
SYNTAX SnmpAdminString
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"A textual description of the logical entity. This object
should contain a string which identifies the manufacturer's
name for the logical entity, and should be set to a distinct
value for each version of the logical entity. "
::= { entLogicalEntry 2 }
entLogicalType OBJECT-TYPE
SYNTAX AutonomousType
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"An indication of the type of logical entity. This will
typically be the OBJECT IDENTIFIER name of the node in the
SMI's naming hierarchy which represents the major MIB
module, or the majority of the MIB modules, supported by the
logical entity. For example:
a logical entity of a regular host/router -> mib-2
a logical entity of a 802.1d bridge -> dot1dBridge
a logical entity of a 802.3 repeater -> snmpDot3RptrMgmt
If an appropriate node in the SMI's naming hierarchy cannot
be identified, the value 'mib-2' should be used."
::= { entLogicalEntry 3 }entLogicalDescr is the human-readable label with the manufacturer name and a unique value per version 💖 and entLogicalType is the "what kind of thing is this" field, with examples like mib-2 for a regular host or router, dot1dBridge for an 802.1d bridge, and snmpDot3RptrMgmt for an 802.3 repeater 🦋 if nothing fits, the fallback is 'mib-2' 🌈
entLogicalCommunity OBJECT-TYPE
SYNTAX OCTET STRING (SIZE (0..255))
MAX-ACCESS read-only
STATUS deprecated
DESCRIPTION
"An SNMPv1 or SNMPv2C community-string which can be used to
access detailed management information for this logical
entity. The agent should allow read access with this
community string (to an appropriate subset of all managed
objects) and may also return a community string based on the
privileges of the request used to read this object. Note
that an agent may return a community string with read-only
privileges, even if this object is accessed with a read-
write community string. However, the agent must take care
not to return a community string which allows more
privileges than the community string used to access this
object.
A compliant SNMP agent may wish to conserve naming scopes by
representing multiple logical entities in a single 'default'
naming scope. This is possible when the logical entities
represented by the same value of entLogicalCommunity have no
object instances in common. For example, 'bridge1' and
'repeater1' may be part of the main naming scope, but at
least one additional community string is needed to represent
'bridge2' and 'repeater2'.
Logical entities 'bridge1' and 'repeater1' would be
represented by sysOREntries associated with the 'default'
naming scope.
For agents not accessible via SNMPv1 or SNMPv2C, the value
of this object is the empty string. This object may also
contain an empty string if a community string has not yet
been assigned by the agent, or no community string with
suitable access rights can be returned for a particular SNMP
request.
Note that this object is deprecated. Agents which implement
SNMPv3 access should use the entLogicalContextEngineID and
entLogicalContextName objects to identify the context
associated with each logical entity. SNMPv3 agents may
return a zero-length string for this object, or may continue
to return a community string (e.g., tri-lingual agent
support)."
::= { entLogicalEntry 4 }entLogicalCommunity is the spicy one 🌶️ it's an SNMPv1 or SNMPv2C community string, and it's been marked deprecated, so the text sends SNMPv3 agents over to entLogicalContextEngineID and entLogicalContextName instead 💅 there's also a whole bit about sharing one 'default' naming scope between logical entities that have no object instances in common, with bridge1 and repeater1 as the example 🧚
the access rules in here are a lot, bestie: read the whole thing before you touch it 😭
entLogicalTAddress OBJECT-TYPE
SYNTAX TAddress
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The transport service address by which the logical entity
receives network management traffic, formatted according to
the corresponding value of entLogicalTDomain.
For snmpUDPDomain, a TAddress is 6 octets long, the initial
4 octets containing the IP-address in network-byte order and
the last 2 containing the UDP port in network-byte order.
Consult 'Transport Mappings for Version 2 of the Simple
Network Management Protocol' (RFC 1906 [RFC1906]) for
further information on snmpUDPDomain."
::= { entLogicalEntry 5 }
entLogicalTDomain OBJECT-TYPE
SYNTAX TDomain
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"Indicates the kind of transport service by which the
logical entity receives network management traffic.
Possible values for this object are presently found in the
Transport Mappings for SNMPv2 document (RFC 1906
[RFC1906])."
::= { entLogicalEntry 6 }entLogicalTAddress is the address where the logical entity catches its management traffic 📮 for snmpUDPDomain it's 6 octets: 4 for the IP address and 2 for the UDP port, both in network-byte order 🌸 and entLogicalTDomain tells you what kind of transport it is, with the possible values living over in RFC 1906 [RFC1906] 🦋
entLogicalContextEngineID OBJECT-TYPE
SYNTAX SnmpEngineIdOrNone
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The authoritative contextEngineID that can be used to send
an SNMP message concerning information held by this logical
entity, to the address specified by the associated
'entLogicalTAddress/entLogicalTDomain' pair.
This object, together with the associated
entLogicalContextName object, defines the context associated
with a particular logical entity, and allows access to SNMP
engines identified by a contextEngineId and contextName
pair.
If no value has been configured by the agent, a zero-length
string is returned, or the agent may choose not to
instantiate this object at all."
::= { entLogicalEntry 7 }
entLogicalContextName OBJECT-TYPE
SYNTAX SnmpAdminString
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The contextName that can be used to send an SNMP message
concerning information held by this logical entity, to the
address specified by the associated
'entLogicalTAddress/entLogicalTDomain' pair.
This object, together with the associated
entLogicalContextEngineID object, defines the context
associated with a particular logical entity, and allows
access to SNMP engines identified by a contextEngineId and
contextName pair.
If no value has been configured by the agent, a zero-length
string is returned, or the agent may choose not to
instantiate this object at all."
::= { entLogicalEntry 8 }these two are a power couple 👑 entLogicalContextEngineID and entLogicalContextName work together to define the context for a logical entity, so you can reach the right SNMP engine using the contextEngineId and contextName pair 💜 if nothing's been configured, you get a zero-length string, or the agent can skip instantiating them entirely 🙈
Now the mapping tables, which tie logical entities to the physical gear underneath them 🔗
entLPMappingTable OBJECT-TYPE
SYNTAX SEQUENCE OF EntLPMappingEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"This table contains zero or more rows of logical entity to
physical equipment associations. For each logical entity
known by this agent, there are zero or more mappings to the
physical resources which are used to realize that logical
entity.
An agent should limit the number and nature of entries in
this table such that only meaningful and non-redundant
information is returned. For example, in a system which
contains a single power supply, mappings between logical
entities and the power supply are not useful and should not
be included.
Also, only the most appropriate physical component which is
closest to the root of a particular containment tree should
be identified in an entLPMapping entry.
For example, suppose a bridge is realized on a particular
module, and all ports on that module are ports on this
bridge. A mapping between the bridge and the module would be
useful, but additional mappings between the bridge and each
of the ports on that module would be redundant (since the
entPhysicalContainedIn hierarchy can provide the same
information). If, on the other hand, more than one bridge
was utilizing ports on this module, then mappings between
each bridge and the ports it used would be appropriate.
Also, in the case of a single backplane repeater, a mapping
for the backplane to the single repeater entity is not
necessary."
::= { entityMapping 1 }
entLPMappingEntry OBJECT-TYPE
SYNTAX EntLPMappingEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"Information about a particular logical entity to physical
equipment association. Note that the nature of the
association is not specifically identified in this entry.
It is expected that sufficient information exists in the
MIBs used to manage a particular logical entity to infer how
physical component information is utilized."
INDEX { entLogicalIndex, entLPPhysicalIndex }
::= { entLPMappingTable 1 }
EntLPMappingEntry ::= SEQUENCE {
entLPPhysicalIndex PhysicalIndex
}
entLPPhysicalIndex OBJECT-TYPE
SYNTAX PhysicalIndex
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The value of this object identifies the index value of a
particular entPhysicalEntry associated with the indicated
entLogicalEntity."
::= { entLPMappingEntry 1 }entLPMappingTable is the logical-to-physical map 🗺️ the vibe is "only keep the useful stuff," so the text says to skip redundant rows 💅 a single power supply? not worth a mapping 🙄 and if one bridge sits on a module, you only map the bridge to the module, because entPhysicalContainedIn already covers the ports 🧚 the entries are indexed by entLogicalIndex and entLPPhysicalIndex, and the physical index just points at a particular entPhysicalEntry ✨
-- logical entity/component to alias table
entAliasMappingTable OBJECT-TYPE
SYNTAX SEQUENCE OF EntAliasMappingEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"This table contains zero or more rows, representing
mappings of logical entity and physical component to
external MIB identifiers. Each physical port in the system
may be associated with a mapping to an external identifier,
which itself is associated with a particular logical
entity's naming scope. A 'wildcard' mechanism is provided
to indicate that an identifier is associated with more than
one logical entity."
::= { entityMapping 2 }
entAliasMappingEntry OBJECT-TYPE
SYNTAX EntAliasMappingEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"Information about a particular physical equipment, logical
entity to external identifier binding. Each logical
entity/physical component pair may be associated with one
alias mapping. The logical entity index may also be used as
a 'wildcard' (refer to the entAliasLogicalIndexOrZero object
DESCRIPTION clause for details.)
Note that only entPhysicalIndex values which represent
physical ports (i.e. associated entPhysicalClass value is
'port(10)') are permitted to exist in this table."
INDEX { entPhysicalIndex, entAliasLogicalIndexOrZero }
::= { entAliasMappingTable 1 }last but not least, entAliasMappingTable is the alias table 🎀 it links physical ports to external MIB identifiers that belong to a logical entity's naming scope, and there's a 'wildcard' trick for when one identifier covers several logical entities 🦋 the entries only allow entPhysicalIndex values for ports, meaning entPhysicalClass is 'port(10)' 🌈
More of this coming up, bestie 💖🧚
okay bestie, the alias and containment tables are next, and they are giving organised energy 🦋✨
EntAliasMappingEntry ::= SEQUENCE {
entAliasLogicalIndexOrZero INTEGER,
entAliasMappingIdentifier RowPointer
}
entAliasLogicalIndexOrZero OBJECT-TYPE
SYNTAX INTEGER (0..2147483647)
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"The value of this object identifies the logical entity
which defines the naming scope for the associated instance
of the 'entAliasMappingIdentifier' object.
If this object has a non-zero value, then it identifies the
logical entity named by the same value of entLogicalIndex.
If this object has a value of zero, then the mapping between
the physical component and the alias identifier for this
entAliasMapping entry is associated with all unspecified
logical entities. That is, a value of zero (the default
mapping) identifies any logical entity which does not have
an explicit entry in this table for a particular
entPhysicalIndex/entAliasMappingIdentifier pair.
For example, to indicate that a particular interface (e.g.,
physical component 33) is identified by the same value of
ifIndex for all logical entities, the following instance
might exist:
entAliasMappingIdentifier.33.0 = ifIndex.5
In the event an entPhysicalEntry is associated differently
for some logical entities, additional entAliasMapping
entries may exist, e.g.:
entAliasMappingIdentifier.33.0 = ifIndex.6
entAliasMappingIdentifier.33.4 = ifIndex.1
entAliasMappingIdentifier.33.5 = ifIndex.1
entAliasMappingIdentifier.33.10 = ifIndex.12
Note that entries with non-zero entAliasLogicalIndexOrZero
index values have precedence over any zero-indexed entry. In
this example, all logical entities except 4, 5, and 10,
associate physical entity 33 with ifIndex.6."
::= { entAliasMappingEntry 1 }
entAliasMappingIdentifier OBJECT-TYPE
SYNTAX RowPointer
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The value of this object identifies a particular conceptual
row associated with the indicated entPhysicalIndex and
entLogicalIndex pair.
Since only physical ports are modeled in this table, only
entries which represent interfaces or ports are allowed. If
an ifEntry exists on behalf of a particular physical port,
then this object should identify the associated 'ifEntry'.
For repeater ports, the appropriate row in the
'rptrPortGroupTable' should be identified instead.
For example, suppose a physical port was represented by
entPhysicalEntry.3, entLogicalEntry.15 existed for a
repeater, and entLogicalEntry.22 existed for a bridge. Then
there might be two related instances of
entAliasMappingIdentifier:
entAliasMappingIdentifier.3.15 == rptrPortGroupIndex.5.2
entAliasMappingIdentifier.3.22 == ifIndex.17
It is possible that other mappings (besides interfaces and
repeater ports) may be defined in the future, as required.
Bridge ports are identified by examining the Bridge MIB and
appropriate ifEntries associated with each 'dot1dBasePort',
and are thus not represented in this table."
::= { entAliasMappingEntry 2 }
-- physical mapping table
entPhysicalContainsTable OBJECT-TYPE
SYNTAX SEQUENCE OF EntPhysicalContainsEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A table which exposes the container/'containee'
relationships between physical entities. This table provides
all the information found by constructing the virtual
containment tree for a given entPhysicalTable, but in a more
direct format.
In the event a physical entity is contained by more than one
other physical entity (e.g., double-wide modules), this
table should include these additional mappings, which cannot
be represented in the entPhysicalTable virtual containment
tree."
::= { entityMapping 3 }
entPhysicalContainsEntry OBJECT-TYPE
SYNTAX EntPhysicalContainsEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"A single container/'containee' relationship."
INDEX { entPhysicalIndex, entPhysicalChildIndex }
::= { entPhysicalContainsTable 1 }
EntPhysicalContainsEntry ::= SEQUENCE {
entPhysicalChildIndex PhysicalIndex
}
entPhysicalChildIndex OBJECT-TYPE
SYNTAX PhysicalIndex
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The value of entPhysicalIndex for the contained physical
entity."
::= { entPhysicalContainsEntry 1 }
-- last change time stamp for the whole MIB
entLastChangeTime OBJECT-TYPE
SYNTAX TimeStamp
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The value of sysUpTime at the time a conceptual row is
created, modified, or deleted in any of these tables:
- entPhysicalTable
- entLogicalTable
- entLPMappingTable
- entAliasMappingTable
- entPhysicalContainsTable
"
::= { entityGeneral 1 }
-- Entity MIB Trap Definitions
entityMIBTraps OBJECT IDENTIFIER ::= { entityMIB 2 }
entityMIBTrapPrefix OBJECT IDENTIFIER ::= { entityMIBTraps 0 }
entConfigChange NOTIFICATION-TYPE
STATUS current
DESCRIPTION
"An entConfigChange notification is generated when the value
of entLastChangeTime changes. It can be utilized by an NMS
to trigger logical/physical entity table maintenance polls.
An agent should not generate more than one entConfigChange
'notification-event' in a given time interval (five seconds
is the suggested default). A 'notification-event' is the
transmission of a single trap or inform PDU to a list of
notification destinations.
If additional configuration changes occur within the
throttling period, then notification-events for these
changes should be suppressed by the agent until the current
throttling period expires. At the end of a throttling
period, one notification-event should be generated if any
configuration changes occurred since the start of the
throttling period. In such a case, another throttling period
is started right away.
An NMS should periodically check the value of
entLastChangeTime to detect any missed entConfigChange
notification-events, e.g., due to throttling or transmission
loss."
::= { entityMIBTrapPrefix 1 }
-- conformance information
entityConformance OBJECT IDENTIFIER ::= { entityMIB 3 }
entityCompliances OBJECT IDENTIFIER ::= { entityConformance 1 }
entityGroups OBJECT IDENTIFIER ::= { entityConformance 2 }
-- compliance statements
entityCompliance MODULE-COMPLIANCE
STATUS deprecated
DESCRIPTION
"The compliance statement for SNMP entities which implement
version 1 of the Entity MIB."
MODULE -- this module
MANDATORY-GROUPS {
entityPhysicalGroup,
entityLogicalGroup,
entityMappingGroup,
entityGeneralGroup,
entityNotificationsGroup
}
::= { entityCompliances 1 }
entity2Compliance MODULE-COMPLIANCE
STATUS current
DESCRIPTION
"The compliance statement for SNMP entities which implement
version 2 of the Entity MIB."
MODULE -- this module
MANDATORY-GROUPS {
entityPhysicalGroup,
entityPhysical2Group,
entityGeneralGroup,
entityNotificationsGroup
}
GROUP entityLogical2Group
DESCRIPTION
"Implementation of this group is not mandatory for agents
which model all MIB object instances within a single naming
scope."
GROUP entityMappingGroup
DESCRIPTION
"Implementation of the entPhysicalContainsTable is mandatory
for all agents. Implementation of the entLPMappingTable and
entAliasMappingTables are not mandatory for agents which
model all MIB object instances within a single naming scope.
Note that the entAliasMappingTable may be useful for all
agents, however implementation of the entityLogicalGroup or
entityLogical2Group is required to support this table."
OBJECT entPhysicalSerialNum
MIN-ACCESS not-accessible
DESCRIPTION
"Read and write access is not required for agents which
cannot identify serial number information for physical
entities, and/or cannot provide non-volatile storage for
NMS-assigned serial numbers.
Write access is not required for agents which can identify
serial number information for physical entities, but cannot
provide non-volatile storage for NMS-assigned serial
numbers.
Write access is not required for physical entities for
physical entities for which the associated value of the
entPhysicalIsFRU object is equal to 'false(2)'."
OBJECT entPhysicalAlias
MIN-ACCESS read-only
DESCRIPTION
"Write access is required only if the associated
entPhysicalClass value is equal to 'chassis(3)'."
OBJECT entPhysicalAssetID
MIN-ACCESS not-accessible
DESCRIPTION
"Read and write access is not required for agents which
cannot provide non-volatile storage for NMS-assigned asset
identifiers.
Write access is not required for physical entities for which
the associated value of entPhysicalIsFRU is equal to
'false(2)'."
::= { entityCompliances 2 }-- MIB groupings
entityPhysicalGroup OBJECT-GROUP
OBJECTS {
entPhysicalDescr,
entPhysicalVendorType,
entPhysicalContainedIn,
entPhysicalClass,
entPhysicalParentRelPos,
entPhysicalName
}
STATUS current
DESCRIPTION
"The collection of objects which are used to represent
physical system components, for which a single agent
provides management information."
::= { entityGroups 1 }
entityLogicalGroup OBJECT-GROUP
OBJECTS {
entLogicalDescr,
entLogicalType,
entLogicalCommunity,
entLogicalTAddress,
entLogicalTDomain
}
STATUS deprecated
DESCRIPTION
"The collection of objects which are used to represent the
list of logical entities for which a single agent provides
management information."
::= { entityGroups 2 }
entityMappingGroup OBJECT-GROUP
OBJECTS {
entLPPhysicalIndex,
entAliasMappingIdentifier,
entPhysicalChildIndex
}
STATUS current
DESCRIPTION
"The collection of objects which are used to represent the
associations between multiple logical entities, physical
components, interfaces, and port identifiers for which a
single agent provides management information."
::= { entityGroups 3 }
entityGeneralGroup OBJECT-GROUP
OBJECTS {
entLastChangeTime
}
STATUS current
DESCRIPTION
"The collection of objects which are used to represent
general entity information for which a single agent provides
management information."
::= { entityGroups 4 }
entityNotificationsGroup NOTIFICATION-GROUP
NOTIFICATIONS { entConfigChange }
STATUS current
DESCRIPTION
"The collection of notifications used to indicate Entity MIB
data consistency and general status information."
::= { entityGroups 5 }
entityPhysical2Group OBJECT-GROUP
OBJECTS {
entPhysicalHardwareRev,
entPhysicalFirmwareRev,
entPhysicalSoftwareRev,
entPhysicalSerialNum,
entPhysicalMfgName,
entPhysicalModelName,
entPhysicalAlias,
entPhysicalAssetID,
entPhysicalIsFRU
}
STATUS current
DESCRIPTION
"The collection of objects which are used to represent
physical system components, for which a single agent
provides management information. This group augments the
objects contained in the entityPhysicalGroup."
::= { entityGroups 6 }
entityLogical2Group OBJECT-GROUP
OBJECTS {
entLogicalDescr,
entLogicalType,
entLogicalTAddress,
entLogicalTDomain,
entLogicalContextEngineID,
entLogicalContextName
}
STATUS current
DESCRIPTION
"The collection of objects which are used to represent the
list of logical entities for which a single SNMP entity
provides management information."
::= { entityGroups 7 }
END4. Usage Examples ✨
okay so this is the fun part 💖 we're going to walk through the instance values for two example networking devices, and they're kept super simple so they're easy to vibe with 🎀 real gear is way messier, so just know that auxiliary stuff like fans, sensors, empty slots, and sub-modules is not shown here, even though real implementations might totally model it 🧚
4.1. Router/Bridge 🦋
picture a router with two slots 🌸 each slot holds a 3-port router/bridge module, and every port shows up in the ifTable 💅 on top of that, there are two logical instances of OSPF running and two logical bridges, so it's giving main character energy 👑
Physical entities -- entPhysicalTable:
1 Field-replaceable physical chassis:
entPhysicalDescr.1 == 'Acme Chassis Model 100'
entPhysicalVendorType.1 == acmeProducts.chassisTypes.1
entPhysicalContainedIn.1 == 0
entPhysicalClass.1 == chassis(3)
entPhysicalParentRelPos.1 == 0
entPhysicalName.1 == '100-A'
entPhysicalHardwareRev.1 == 'A(1.00.02)'
entPhysicalSoftwareRev.1 == ''
entPhysicalFirmwareRev.1 == ''
entPhysicalSerialNum.1 == 'C100076544'
entPhysicalMfgName.1 == 'Acme'
entPhysicalModelName.1 == '100'
entPhysicalAlias.1 == 'cl-SJ17-3-006:rack1:rtr-U3'
entPhysicalAssetID.1 == '0007372293'
entPhysicalIsFRU.1 == true(1)
2 slots within the chassis:
entPhysicalDescr.2 == 'Acme Chassis Slot Type AA'
entPhysicalVendorType.2 == acmeProducts.slotTypes.1
entPhysicalContainedIn.2 == 1
entPhysicalClass.2 == container(5)
entPhysicalParentRelPos.2 == 1
entPhysicalName.2 == 'S1'
entPhysicalHardwareRev.2 == 'B(1.00.01)'
entPhysicalSoftwareRev.2 == ''
entPhysicalFirmwareRev.2 == ''
entPhysicalSerialNum.2 == ''
entPhysicalMfgName.2 == 'Acme'
entPhysicalModelName.2 == 'AA'
entPhysicalAlias.2 == ''
entPhysicalAssetID.2 == ''
entPhysicalIsFRU.2 == false(2)
entPhysicalDescr.3 == 'Acme Chassis Slot Type AA'
entPhysicalVendorType.3 = acmeProducts.slotTypes.1
entPhysicalContainedIn.3 == 1
entPhysicalClass.3 == container(5)
entPhysicalParentRelPos.3 == 2
entPhysicalName.3 == 'S2'
entPhysicalHardwareRev.3 == '1.00.07'
entPhysicalSoftwareRev.3 == ''
entPhysicalFirmwareRev.3 == ''
entPhysicalSerialNum.3 == ''
entPhysicalMfgName.3 == 'Acme'
entPhysicalModelName.3 == 'AA'
entPhysicalAlias.3 == ''
entPhysicalAssetID.3 == ''
entPhysicalIsFRU.3 == false(2)
2 Field-replaceable modules:
Slot 1 contains a module with 3 ports:
entPhysicalDescr.4 == 'Acme Router-100'
entPhysicalVendorType.4 == acmeProducts.moduleTypes.14
entPhysicalContainedIn.4 == 2
entPhysicalClass.4 == module(9)
entPhysicalParentRelPos.4 == 1
entPhysicalName.4 == 'M1'
entPhysicalHardwareRev.4 == '1.00.07'
entPhysicalSoftwareRev.4 == '1.4.1'
entPhysicalFirmwareRev.4 == 'A(1.1)'
entPhysicalSerialNum.4 == 'C100087363'
entPhysicalMfgName.4 == 'Acme'
entPhysicalModelName.4 == 'R100-FE'
entPhysicalAlias.4 == 'rtr-U3:m1:SJ17-3-eng'
entPhysicalAssetID.4 == '0007372462'
entPhysicalIsFRU.4 == true(1)
entPhysicalDescr.5 == 'Acme Ethernet-100 Port'
entPhysicalVendorType.5 == acmeProducts.portTypes.2
entPhysicalContainedIn.5 == 4
entPhysicalClass.5 == port(10)
entPhysicalParentRelPos.5 == 1
entPhysicalName.5 == 'P1'
entPhysicalHardwareRev.5 == 'G(1.02)'
entPhysicalSoftwareRev.5 == ''
entPhysicalFirmwareRev.5 == '1.1'
entPhysicalSerialNum.5 == ''
entPhysicalMfgName.5 == 'Acme'
entPhysicalModelName.5 == 'FE-100'
entPhysicalAlias.5 == ''
entPhysicalAssetID.5 == ''
entPhysicalIsFRU.5 == false(2)
entPhysicalDescr.6 == 'Acme Ethernet-100 Port'
entPhysicalVendorType.6 == acmeProducts.portTypes.2
entPhysicalContainedIn.6 == 4
entPhysicalClass.6 == port(10)
entPhysicalParentRelPos.6 == 2
entPhysicalName.6 == 'P2'
entPhysicalHardwareRev.6 == 'G(1.02)'
entPhysicalSoftwareRev.6 == ''
entPhysicalFirmwareRev.6 == '1.1'
entPhysicalSerialNum.6 == ''
entPhysicalMfgName.6 == 'Acme'
entPhysicalModelName.6 == 'FE-100'
entPhysicalAlias.6 == ''
entPhysicalAssetID.6 == ''
entPhysicalIsFRU.6 == false(2)
entPhysicalDescr.7 == 'Acme Router-100 FDDI-Port'
entPhysicalVendorType.7 == acmeProducts.portTypes.3
entPhysicalContainedIn.7 == 4
entPhysicalClass.7 == port(10)
entPhysicalParentRelPos.7 == 3
entPhysicalName.7 == 'P3'
entPhysicalHardwareRev.7 == 'B(1.03)'
entPhysicalSoftwareRev.7 == '2.5.1'
entPhysicalFirmwareRev.7 == '2.5F'
entPhysicalSerialNum.7 == ''
entPhysicalMfgName.7 == 'Acme'
entPhysicalModelName.7 == 'FDDI-100'
entPhysicalAlias.7 == ''
entPhysicalAssetID.7 == ''
entPhysicalIsFRU.7 == false(2)
Slot 2 contains another 3-port module:
entPhysicalDescr.8 == 'Acme Router-100 Comm Module'
entPhysicalVendorType.8 == acmeProducts.moduleTypes.15
entPhysicalContainedIn.8 == 3
entPhysicalClass.8 == module(9)
entPhysicalParentRelPos.8 == 1
entPhysicalName.8 == 'M2'
entPhysicalHardwareRev.8 == '2.01.00'
entPhysicalSoftwareRev.8 == '3.0.7'
entPhysicalFirmwareRev.8 == 'A(1.2)'
entPhysicalSerialNum.8 == 'C100098732'
entPhysicalMfgName.8 == 'Acme'
entPhysicalModelName.8 == 'C100'
entPhysicalAlias.8 == 'rtr-U3:m2:SJ17-2-eng'
entPhysicalAssetID.8 == '0007373982'
entPhysicalIsFRU.8 == true(1)
entPhysicalDescr.9 == 'Acme Fddi-100 Port'
entPhysicalVendorType.9 == acmeProducts.portTypes.5
entPhysicalContainedIn.9 == 8
entPhysicalClass.9 == port(10)
entPhysicalParentRelPos.9 == 1
entPhysicalName.9 == 'FDDI Primary'
entPhysicalHardwareRev.9 == 'CC(1.07)'
entPhysicalSoftwareRev.9 == '2.0.34'
entPhysicalFirmwareRev.9 == '1.1'
entPhysicalSerialNum.9 == ''
entPhysicalMfgName.9 == 'Acme'
entPhysicalModelName.9 == 'FDDI-100'
entPhysicalAlias.9 == ''
entPhysicalAssetID.9 == ''
entPhysicalIsFRU.9 == false(2) entPhysicalDescr.10 == 'Acme Ethernet-100 Port'
entPhysicalVendorType.10 == acmeProducts.portTypes.2
entPhysicalContainedIn.10 == 8
entPhysicalClass.10 == port(10)
entPhysicalParentRelPos.10 == 2
entPhysicalName.10 == 'Ethernet A'
entPhysicalHardwareRev.10 == 'G(1.04)'
entPhysicalSoftwareRev.10 == ''
entPhysicalFirmwareRev.10 == '1.3'
entPhysicalSerialNum.10 == ''
entPhysicalMfgName.10 == 'Acme'
entPhysicalModelName.10 == 'FE-100'
entPhysicalAlias.10 == ''
entPhysicalAssetID.10 == ''
entPhysicalIsFRU.10 == false(2)
entPhysicalDescr.11 == 'Acme Ethernet-100 Port'
entPhysicalVendorType.11 == acmeProducts.portTypes.2
entPhysicalContainedIn.11 == 8
entPhysicalClass.11 == port(10)
entPhysicalParentRelPos.11 == 3
entPhysicalName.11 == 'Ethernet B'
entPhysicalHardwareRev.11 == 'G(1.04)'
entPhysicalSoftwareRev.11 == ''
entPhysicalFirmwareRev.11 == '1.3'
entPhysicalSerialNum.11 == ''
entPhysicalMfgName.11 == 'Acme'
entPhysicalModelName.11 == 'FE-100'
entPhysicalAlias.11 == ''
entPhysicalAssetID.11 == ''
entPhysicalIsFRU.11 == false(2)
Logical entities -- entLogicalTable; no SNMPv3 support
2 OSPF instances:
entLogicalDescr.1 == 'Acme OSPF v1.1'
entLogicalType.1 == ospf
entLogicalCommunity.1 == 'public-ospf1'
entLogicalTAddress.1 == 124.125.126.127:161
entLogicalTDomain.1 == snmpUDPDomain
entLogicalContextEngineID.1 == ''
entLogicalContextName.1 == ''
entLogicalDescr.2 == 'Acme OSPF v1.1'
entLogicalType.2 == ospf
entLogicalCommunity.2 == 'public-ospf2'
entLogicalTAddress.2 == 124.125.126.127:161
entLogicalTDomain.2 == snmpUDPDomain
entLogicalContextEngineID.2 == ''
entLogicalContextName.2 == ''
2 logical bridges:
entLogicalDescr.3 == 'Acme Bridge v2.1.1'
entLogicalType.3 == dot1dBridge
entLogicalCommunity.3 == 'public-bridge1'
entLogicalTAddress.3 == 124.125.126.127:161
entLogicalTDomain.3 == snmpUDPDomain
entLogicalContextEngineID.3 == ''
entLogicalContextName.3 == ''
entLogicalDescr.4 == 'Acme Bridge v2.1.1'
entLogicalType.4 == dot1dBridge
entLogicalCommunity.4 == 'public-bridge2'
entLogicalTAddress.4 == 124.125.126.127:161
entLogicalTDomain.4 == snmpUDPDomain
entLogicalContextEngineID.4 == ''
entLogicalContextName.4 == ''
Logical to Physical Mappings:
1st OSPF instance: uses module 1-port 1
entLPPhysicalIndex.1.5 == 5
2nd OSPF instance: uses module 2-port 1
entLPPhysicalIndex.2.9 == 9
1st bridge group: uses module 1, all ports
[ed. -- Note that these mappings are included in the table since
another logical entity (1st OSPF) utilizes one of the
ports. If this were not the case, then a single mapping
to the module (e.g., entLPPhysicalIndex.3.4) would be
present instead. ]
entLPPhysicalIndex.3.5 == 5
entLPPhysicalIndex.3.6 == 6
entLPPhysicalIndex.3.7 == 7
2nd bridge group: uses module 2, all ports
entLPPhysicalIndex.4.9 == 9
entLPPhysicalIndex.4.10 == 10
entLPPhysicalIndex.4.11 == 11
Physical to Logical to MIB Alias Mappings -- entAliasMappingTable:
Example 1: ifIndex values are global to all logical entities
entAliasMappingIdentifier.5.0 == ifIndex.1
entAliasMappingIdentifier.6.0 == ifIndex.2
entAliasMappingIdentifier.7.0 == ifIndex.3
entAliasMappingIdentifier.9.0 == ifIndex.4
entAliasMappingIdentifier.10.0 == ifIndex.5
entAliasMappingIdentifier.11.0 == ifIndex.6
Example 2: ifIndex values are not shared by all logical entities
entAliasMappingIdentifier.5.0 == ifIndex.1
entAliasMappingIdentifier.5.3 == ifIndex.101
entAliasMappingIdentifier.6.0 == ifIndex.2
entAliasMappingIdentifier.6.3 == ifIndex.102
entAliasMappingIdentifier.7.0 == ifIndex.3
entAliasMappingIdentifier.7.3 == ifIndex.103
entAliasMappingIdentifier.9.0 == ifIndex.4
entAliasMappingIdentifier.9.3 == ifIndex.204
entAliasMappingIdentifier.10.0 == ifIndex.5
entAliasMappingIdentifier.10.3 == ifIndex.205
entAliasMappingIdentifier.11.0 == ifIndex.6
entAliasMappingIdentifier.11.3 == ifIndex.206
Physical Containment Tree -- entPhysicalContainsTable
chassis has two containers:
entPhysicalChildIndex.1.2 == 2
entPhysicalChildIndex.1.3 == 3
container 1 has a module:
entPhysicalChildIndex.2.4 == 4
container 2 has a module:
entPhysicalChildIndex.3.8 == 8
module 1 has 3 ports:
entPhysicalChildIndex.4.5 == 5
entPhysicalChildIndex.4.6 == 6
entPhysicalChildIndex.4.7 == 7
module 2 has 3 ports:
entPhysicalChildIndex.8.9 == 9
entPhysicalChildIndex.8.10 == 10
entPhysicalChildIndex.1.11 == 114.2. Repeaters ✨
okay so picture a 3-slot Hub 🧚 with 2 backplane ethernet segments 🔌. Slot three is empty 🫥, and the other slots hold ethernet repeater modules 💖.
ngl this example is assuming an older Repeater MIB implementation, RFC 1516 [RFC1516], and NOT the new Repeater MIB, RFC 2108 [RFC2108] 🙈. The newer version has an object called rptrPortRptrId, and that's the one you should use to identify repeater port groupings, rather than community strings or contexts 🎀 iykyk.
okay bestie, the physical gear comes first 🎀 then the logical stuff riding on top 🦋, then how the two get matched up 💅
Physical entities -- entPhysicalTable:
1 Field-replaceable physical chassis:
entPhysicalDescr.1 == 'Acme Chassis Model 110'
entPhysicalVendorType.1 == acmeProducts.chassisTypes.2
entPhysicalContainedIn.1 == 0
entPhysicalClass.1 == chassis(3)
entPhysicalParentRelPos.1 == 0
entPhysicalName.1 == '110-B'
entPhysicalHardwareRev.1 == 'A(1.02.00)'
entPhysicalSoftwareRev.1 == ''
entPhysicalFirmwareRev.1 == ''
entPhysicalSerialNum.1 == 'C100079294'
entPhysicalMfgName.1 == 'Acme'
entPhysicalModelName.1 == '110'
entPhysicalAlias.1 == 'bldg09:floor1:rptr18:0067eea0229f'
entPhysicalAssetID.1 == '0007386327'
entPhysicalIsFRU.1 == true(1)
2 Chassis Ethernet Backplanes:
entPhysicalDescr.2 == 'Acme Ethernet Backplane Type A'
entPhysicalVendorType.2 == acmeProducts.backplaneTypes.1
entPhysicalContainedIn.2 == 1
entPhysicalClass.2 == backplane(4)
entPhysicalParentRelPos.2 == 1
entPhysicalName.2 == 'B1'
entPhysicalHardwareRev.2 == 'A(2.04.01)'
entPhysicalSoftwareRev.2 == ''
entPhysicalFirmwareRev.2 == ''
entPhysicalSerialNum.2 == ''
entPhysicalMfgName.2 == 'Acme'
entPhysicalModelName.2 == 'BK-A'
entPhysicalAlias.2 == ''
entPhysicalAssetID.2 == ''
entPhysicalIsFRU.2 == false(2)
entPhysicalDescr.3 == 'Acme Ethernet Backplane Type A'
entPhysicalVendorType.3 == acmeProducts.backplaneTypes.1
entPhysicalContainedIn.3 == 1
entPhysicalClass.3 == backplane(4)
entPhysicalParentRelPos.3 == 2
entPhysicalName.3 == 'B2'
entPhysicalHardwareRev.3 == 'A(2.04.01)'
entPhysicalSoftwareRev.3 == ''
entPhysicalFirmwareRev.3 == ''
entPhysicalSerialNum.3 == ''
entPhysicalMfgName.3 == 'Acme'
entPhysicalModelName.3 == 'BK-A'
entPhysicalAlias.3 == ''
entPhysicalAssetID.3 == ''
entPhysicalIsFRU.3 == false(2)
3 slots within the chassis:
entPhysicalDescr.4 == 'Acme Hub Slot Type RB'
entPhysicalVendorType.4 == acmeProducts.slotTypes.5
entPhysicalContainedIn.4 == 1
entPhysicalClass.4 == container(5)
entPhysicalParentRelPos.4 == 1
entPhysicalName.4 == 'Slot 1'
entPhysicalHardwareRev.4 == 'B(1.00.03)'
entPhysicalSoftwareRev.4 == ''
entPhysicalFirmwareRev.4 == ''
entPhysicalSerialNum.4 == ''
entPhysicalMfgName.4 == 'Acme'
entPhysicalModelName.4 == 'RB'
entPhysicalAlias.4 == ''
entPhysicalAssetID.4 == ''
entPhysicalIsFRU.4 == false(2)
entPhysicalDescr.5 == 'Acme Hub Slot Type RB'
entPhysicalVendorType.5 == acmeProducts.slotTypes.5
entPhysicalContainedIn.5 == 1
entPhysicalClass.5 == container(5)
entPhysicalParentRelPos.5 == 2
entPhysicalName.5 == 'Slot 2'
entPhysicalHardwareRev.5 == 'B(1.00.03)'
entPhysicalSoftwareRev.5 == ''
entPhysicalFirmwareRev.5 == ''
entPhysicalSerialNum.5 == ''
entPhysicalMfgName.5 == 'Acme'
entPhysicalModelName.5 == 'RB'
entPhysicalAlias.5 == ''
entPhysicalAssetID.5 == ''
entPhysicalIsFRU.5 == false(2)
entPhysicalDescr.6 == 'Acme Hub Slot Type RB'
entPhysicalVendorType.6 == acmeProducts.slotTypes.5
entPhysicalContainedIn.6 == 1
entPhysicalClass.6 == container(5)
entPhysicalParentRelPos.6 == 3
entPhysicalName.6 == 'Slot 3'
entPhysicalHardwareRev.6 == 'B(1.00.03)'
entPhysicalSoftwareRev.6 == ''
entPhysicalFirmwareRev.6 == ''
entPhysicalSerialNum.6 == ''
entPhysicalMfgName.6 == 'Acme'
entPhysicalModelName.6 == 'RB'
entPhysicalAlias.6 == ''
entPhysicalAssetID.6 == ''
entPhysicalIsFRU.6 == false(2)
Slot 1 contains a plug-in module with 4 10-BaseT ports:
entPhysicalDescr.7 == 'Acme 10Base-T Module 114'
entPhysicalVendorType.7 == acmeProducts.moduleTypes.32
entPhysicalContainedIn.7 == 4
entPhysicalClass.7 == module(9)
entPhysicalParentRelPos.7 == 1
entPhysicalName.7 == 'M1'
entPhysicalHardwareRev.7 == 'A(1.02.01)'
entPhysicalSoftwareRev.7 == '1.7.2'
entPhysicalFirmwareRev.7 == 'A(1.5)'
entPhysicalSerialNum.7 == 'C100096244'
entPhysicalMfgName.7 == 'Acme'
entPhysicalModelName.7 = '114'
entPhysicalAlias.7 == 'bldg09:floor1:eng'
entPhysicalAssetID.7 == '0007962951'
entPhysicalIsFRU.7 == true(1)
entPhysicalDescr.8 == 'Acme 10Base-T Port RB'
entPhysicalVendorType.8 == acmeProducts.portTypes.10
entPhysicalContainedIn.8 == 7
entPhysicalClass.8 == port(10)
entPhysicalParentRelPos.8 == 1
entPhysicalName.8 == 'Ethernet-A'
entPhysicalHardwareRev.8 == 'A(1.04F)'
entPhysicalSoftwareRev.8 == ''
entPhysicalFirmwareRev.8 == '1.4'
entPhysicalSerialNum.8 == ''
entPhysicalMfgName.8 == 'Acme'
entPhysicalModelName.8 == 'RB'
entPhysicalAlias.8 == ''
entPhysicalAssetID.8 == ''
entPhysicalIsFRU.8 == false(2)
entPhysicalDescr.9 == 'Acme 10Base-T Port RB'
entPhysicalVendorType.9 == acmeProducts.portTypes.10
entPhysicalContainedIn.9 == 7
entPhysicalClass.9 == port(10)
entPhysicalParentRelPos.9 == 2
entPhysicalName.9 == 'Ethernet-B'
entPhysicalHardwareRev.9 == 'A(1.04F)'
entPhysicalSoftwareRev.9 == ''
entPhysicalFirmwareRev.9 == '1.4'
entPhysicalSerialNum.9 == ''
entPhysicalMfgName.9 == 'Acme'
entPhysicalModelName.9 = 'RB'
entPhysicalAlias.9 == ''
entPhysicalAssetID.9 == ''
entPhysicalIsFRU.9 == false(2)
entPhysicalDescr.10 == 'Acme 10Base-T Port RB'
entPhysicalVendorType.10 == acmeProducts.portTypes.10
entPhysicalContainedIn.10 == 7
entPhysicalClass.10 == port(10)
entPhysicalParentRelPos.10 == 3
entPhysicalName.10 == 'Ethernet-C'
entPhysicalHardwareRev.10 == 'B(1.02.07)'
entPhysicalSoftwareRev.10 == ''
entPhysicalFirmwareRev.10 == '1.4'
entPhysicalSerialNum.10 == ''
entPhysicalMfgName.10 == 'Acme'
entPhysicalModelName.10 == 'RB'
entPhysicalAlias.10 == ''
entPhysicalAssetID.10 == ''
entPhysicalIsFRU.10 == false(2)
entPhysicalDescr.11 == 'Acme 10Base-T Port RB'
entPhysicalVendorType.11 == acmeProducts.portTypes.10
entPhysicalContainedIn.11 == 7
entPhysicalClass.11 == port(10)
entPhysicalParentRelPos.11 == 4
entPhysicalName.11 == 'Ethernet-D'
entPhysicalHardwareRev.11 == 'B(1.02.07)'
entPhysicalSoftwareRev.11 == ''
entPhysicalFirmwareRev.11 == '1.4'
entPhysicalSerialNum.11 == ''
entPhysicalMfgName.11 == 'Acme'
entPhysicalModelName.11 == 'RB'
entPhysicalAlias.11 == ''
entPhysicalAssetID.11 == ''
entPhysicalIsFRU.11 == false(2)
Slot 2 contains another ethernet module with 2 ports.
entPhysicalDescr.12 == 'Acme 10Base-T Module Model 4'
entPhysicalVendorType.12 == acmeProducts.moduleTypes.30
entPhysicalContainedIn.12 = 5
entPhysicalClass.12 == module(9)
entPhysicalParentRelPos.12 == 1
entPhysicalName.12 == 'M2'
entPhysicalHardwareRev.12 == 'A(1.01.07)'
entPhysicalSoftwareRev.12 == '1.8.4'
entPhysicalFirmwareRev.12 == 'A(1.8)'
entPhysicalSerialNum.12 == 'C100102384'
entPhysicalMfgName.12 == 'Acme'
entPhysicalModelName.12 == '4'
entPhysicalAlias.12 == 'bldg09:floor1:devtest'
entPhysicalAssetID.12 == '0007968462'
entPhysicalIsFRU.12 == true(1)
entPhysicalDescr.13 == 'Acme 802.3 AUI Port'
entPhysicalVendorType.13 == acmeProducts.portTypes.11
entPhysicalContainedIn.13 == 12
entPhysicalClass.13 == port(10)
entPhysicalParentRelPos.13 == 1
entPhysicalName.13 == 'AUI'
entPhysicalHardwareRev.13 == 'A(1.06F)'
entPhysicalSoftwareRev.13 == ''
entPhysicalFirmwareRev.13 == '1.5'
entPhysicalSerialNum.13 == ''
entPhysicalMfgName.13 == 'Acme'
entPhysicalModelName.13 == ''
entPhysicalAlias.13 == ''
entPhysicalAssetID.13 == ''
entPhysicalIsFRU.13 == false(2)
entPhysicalDescr.14 == 'Acme 10Base-T Port RD'
entPhysicalVendorType.14 == acmeProducts.portTypes.14
entPhysicalContainedIn.14 == 12
entPhysicalClass.14 == port(10)
entPhysicalParentRelPos.14 == 2
entPhysicalName.14 == 'E2'
entPhysicalHardwareRev.14 == 'B(1.01.02)'
entPhysicalSoftwareRev.14 == ''
entPhysicalFirmwareRev.14 == '2.1'
entPhysicalSerialNum.14 == ''
entPhysicalMfgName.14 == 'Acme'
entPhysicalModelName.14 == ''
entPhysicalAlias.14 == ''
entPhysicalAssetID.14 == ''
entPhysicalIsFRU.14 == false(2)
Logical entities -- entLogicalTable; with SNMPv3 support
Repeater 1--comprised of any ports attached to backplane 1
entLogicalDescr.1 == 'Acme repeater v3.1'
entLogicalType.1 == snmpDot3RptrMgt
entLogicalCommunity.1 'public-repeater1'
entLogicalTAddress.1 == 124.125.126.127:161
entLogicalTDomain.1 == snmpUDPDomain
entLogicalContextEngineID.1 == '80000777017c7d7e7f'H
entLogicalContextName.1 == 'repeater1'
Repeater 2--comprised of any ports attached to backplane 2:
entLogicalDescr.2 == 'Acme repeater v3.1'
entLogicalType.2 == snmpDot3RptrMgt
entLogicalCommunity.2 == 'public-repeater2'
entLogicalTAddress.2 == 124.125.126.127:161
entLogicalTDomain.2 == snmpUDPDomain
entLogicalContextEngineID.2 == '80000777017c7d7e7f'H
entLogicalContextName.2 == 'repeater2'
Logical to Physical Mappings -- entLPMappingTable:
repeater1 uses backplane 1, slot 1-ports 1 & 2, slot 2-port 1
[ed. -- Note that a mapping to the module is not included,
since in this example represents a port-switchable hub.
Even though all ports on the module could belong to the
same repeater as a matter of configuration, the LP port
mappings should not be replaced dynamically with a single
mapping for the module (e.g., entLPPhysicalIndex.1.7).
If all ports on the module shared a single backplane connection,
then a single mapping for the module would be more appropriate. ]
entLPPhysicalIndex.1.2 == 2
entLPPhysicalIndex.1.8 == 8
entLPPhysicalIndex.1.9 == 9
entLPPhysicalIndex.1.13 == 13
repeater2 uses backplane 2, slot 1-ports 3 & 4, slot 2-port 2
entLPPhysicalIndex.2.3 == 3
entLPPhysicalIndex.2.10 == 10
entLPPhysicalIndex.2.11 == 11
entLPPhysicalIndex.2.14 == 14Okay bestie, so the example below is the entAliasMappingTable flex 💅 Repeater Port Identifiers are shared across both repeaters, so the same port gets the same alias ID in both places 🦋
Physical to Logical to MIB Alias Mappings -- entAliasMappingTable:
Repeater Port Identifier values are shared by both repeaters:
entAliasMappingIdentifier.8.0 == rptrPortGroupIndex.1.1
entAliasMappingIdentifier.9.0 == rptrPortGroupIndex.1.2
entAliasMappingIdentifier.10.0 == rptrPortGroupIndex.1.3
entAliasMappingIdentifier.11.0 == rptrPortGroupIndex.1.4
entAliasMappingIdentifier.13.0 == rptrPortGroupIndex.2.1
entAliasMappingIdentifier.14.0 == rptrPortGroupIndex.2.2
Physical Containment Tree -- entPhysicalContainsTable
chassis has two backplanes and three containers:
entPhysicalChildIndex.1.2 == 2
entPhysicalChildIndex.1.3 == 3
entPhysicalChildIndex.1.4 == 4
entPhysicalChildIndex.1.5 == 5
entPhysicalChildIndex.1.6 == 6
container 1 has a module:
entPhysicalChildIndex.4.7 == 7
container 2 has a module
entPhysicalChildIndex.5.12 == 12
[ed. - in this example, container 3 is empty.]
module 1 has 4 ports:
entPhysicalChildIndex.7.8 == 8
entPhysicalChildIndex.7.9 == 9
entPhysicalChildIndex.7.10 == 10
entPhysicalChildIndex.7.11 == 11
module 2 has 2 ports:
entPhysicalChildIndex.12.13 == 13
entPhysicalChildIndex.12.14 == 14The containment tree is the cutest part ✨ The chassis holds two backplanes and three containers, container 1 holds a module, container 2 holds a module too (and container 3 is empty, which is giving empty shelf 🫶), and then the modules hold their ports. It's like a little family tree of hardware 🌸
5. Intellectual Property 💖
Okay so the IETF doesn't take a position on whether any intellectual property or other rights someone claims apply to the tech in this doc are valid or in scope, and it also doesn't say whether a license is actually available. It hasn't tried to find any of those rights either 🙈 If you want the IETF's rules on rights for standards-track and standards-related docs, check out BCP-11. Any claims of rights that were filed for publication, any licensing assurances, or the results of trying to get a general license for implementers or users can all be requested from the IETF Secretariat 📬
The IETF also invites anyone to tell it about copyrights, patents, patent applications, or other proprietary rights that might cover tech needed to practice this standard. Send that info to the IETF Executive Director 🎀
6. Acknowledgements 🧚
This memo was produced by the IETF's Entity MIB working group. Thank you, legends 👑
7. References 📚
- [RFC1155] Rose, M. and K. McCloghrie, "Structure and Identification of Management Information for TCP/IP-based Internets", STD 16, RFC 1155, May 1990.
- [RFC1157] Case, J., Fedor, M., Schoffstall, M. and J. Davin, "Simple Network Management Protocol", STD 15, RFC 1157, May 1990.
- [RFC1212] Rose, M. and K. McCloghrie, "Concise MIB Definitions", STD 16, RFC 1212, March 1991.
- [RFC1215] Rose, M., "A Convention for Defining Traps for use with the SNMP", RFC 1215, March 1991.
- [RFC1493] Decker, E., Langille, P., Rijsinghani, A. and K. McCloghrie, "Definitions of Managed Objects for Bridges", RFC 1493, July 1993.
- [RFC1516] McMaster, D. and K. McCloghrie, "Definitions of Managed Objects for IEEE 802.3 Repeater Devices", RFC 1516, September 1993.
- [RFC1901] Case, J., McCloghrie, K., Rose, M. and S. Waldbusser, "Introduction to Community-based SNMPv2", RFC 1901, January 1996.
- [RFC1905] Case, J., McCloghrie, K., Rose, M. and S. Waldbusser, "Protocol Operations for Version 2 of the Simple Network Management Protocol (SNMPv2)", RFC 1905, January 1996.
- [RFC1906] Case, J., McCloghrie, K., Rose, M. and S. Waldbusser, "Transport Mappings for Version 2 of the Simple Network Management Protocol (SNMPv2)", RFC 1906, January 1996.
- [RFC2026] Bradner, S., "The Internet Standards Process -- Revision 3", BCP 9, RFC 2026, October 1996.
- [RFC2037] McCloghrie, K. and A. Bierman, "Entity MIB using SMIv2", RFC 2037, October 1996.
- [RFC2108] de Graaf, K., Romascanu, D., McMaster, D. and K. McCloghrie, "Definitions of Managed Objects for IEEE 802.3 Repeater Devices using SMIv2", RFC 2108, February 1997.
- [RFC2233] McCloghrie, K. and F. Kastenholz, "The Interfaces Group MIB Using SMIv2", RFC 2233, November 1997.
- [RFC2570] Case, J., Mundy, R., Partain, D. and B. Stewart, "Introduction to Version 3 of the Internet-standard Network Management Framework", RFC 2570, April 1999.
- [RFC2571] Harrington, D., Presuhn, R. and B. Wijnen, "An Architecture for Describing SNMP Management Frameworks", RFC 2571, April 1999.
- [RFC2572] Case, J., Harrington D., Presuhn R. and B. Wijnen, "Message Processing and Dispatching for the Simple Network Management Protocol (SNMP)", RFC 2572, April 1999.
- [RFC2573] Levi, D., Meyer, P. and B. Stewart, "SNMPv3 Applications", RFC 2573, April 1999.
- [RFC2574] Blumenthal, U. and B. Wijnen, "User-based Security Model (USM) for version 3 of the Simple Network Management Protocol (SNMPv3)", RFC 2574, April 1999.
- [RFC2575] Wijnen, B., Presuhn, R. and K. McCloghrie, "View-based Access Control Model (VACM) for the Simple Network Management Protocol (SNMP)", RFC 2575, April 1999.
- [RFC2578] McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose, M. and S. Waldbusser, "Structure of Management Information Version 2 (SMIv2)", STD 58, RFC 2578, April 1999.
- [RFC2579] McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose, M. and S. Waldbusser, "Textual Conventions for SMIv2", STD 58, RFC 2579, April 1999.
- [RFC2580] McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose, M. and S. Waldbusser, "Conformance Statements for SMIv2", STD 58, RFC 2580, April 1999.
8. Security Considerations 🔥
Okay this section is SERIOUS, so please read it 😭 This MIB defines a bunch of management objects that have a MAX-ACCESS clause of read-write and/or read-create. Those objects might be sensitive or vulnerable in some network environments. Supporting SET operations in a non-secure environment without proper protection can seriously mess with network operations 💀
There are also a bunch of managed objects in this MIB that may hold sensitive info:
entPhysicalDescr
entPhysicalVendorType
entPhysicalHardwareRev
entPhysicalFirmwareRev
entPhysicalSoftwareRev
entPhysicalSerialNum
entPhysicalMfgName
entPhysicalModelNameThese objects expose info about the physical entities inside a managed system, and that can be used to identify the vendor, model, and version info of each system component. Main character villain energy 🦹
entPhysicalAssetIDThis object can let asset identifiers for various system components get exposed, in case this MIB object actually gets configured by an NMS application 🎀
entLogicalDescr
entLogicalTypeThese objects expose the type of logical entities in the managed system.
entLogicalCommunityThis object exposes community names tied to particular logical entities in the system.
entLogicalTAddress
entLogicalTDomainThese objects expose network addresses that can be used to talk to an SNMP agent on behalf of particular logical entities in the system.
entLogicalContextEngineID
entLogicalContextNameThese objects identify the authoritative SNMP engine that holds information on behalf of particular logical entities in the system.
It is thus important to control even GET access to these objects, and possibly to even encrypt the values of these objects when sending them over the network via SNMP. Not all versions of SNMP provide features for such a secure environment. ⚠️
SNMPv1 by itself is not a secure environment 🙅♀️ Even if the network itself is secure (for example by using IPSec), there is still no control over who on that secure network is allowed to access and GET/SET (read/change/create/delete) the objects in this MIB. Not safe, periodt.
The implementers are recommended to consider the security features provided by the SNMPv3 framework 🛡️ Specifically, the User-based Security Model RFC 2574 [RFC2574] and the View-based Access Control Model RFC 2575 [RFC2575] are recommended.
Last but not least, it is then a customer/user responsibility to make sure the SNMP entity giving access to an instance of this MIB is properly configured. Access should only go to those principals (users) who have legitimate rights to GET or SET (change/create/delete) these objects 🫶
12. Authors' Addresses 🦋
Keith McCloghrie
Cisco Systems, Inc.
170 West Tasman Drive
San Jose, CA 95134 USA
Phone: +1 408-526-5260
EMail: kzm@cisco.com
Andy Bierman
Cisco Systems, Inc.
170 West Tasman Drive
San Jose, CA 95134 USA
Phone: +1 408-527-3711
EMail: abierman@cisco.com9. Full Copyright Statement 🌈
Copyright (C) The Internet Society (1999). All Rights Reserved.
This document and translations of it can be copied and handed out to others. Derivative works that comment on or explain it, or help with implementing it, can be made, copied, published, and distributed, in whole or in part, with no restrictions at all. The only condition is that the above copyright notice and this paragraph are included on all copies and derivative works. However, this document itself may not be modified in any way (like removing the copyright notice or the references to the Internet Society or other Internet organizations). The exceptions are when it's needed for developing Internet standards, in which case the copyright procedures in the Internet Standards process must be followed, or when it's translated into languages other than English.
These limited permissions are perpetual and won't be revoked by the Internet Society or its successors or assigns 💜
This document and the information in it are provided on an "AS IS" basis, and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Acknowledgement 🍓
Funding for the RFC Editor function is currently provided by the Internet Society. Thank you for reading, and that's the whole spec, bestie 💅✨
📦 where this page comes from
- ietf: rfc2737 1999-12
- 💖 girlified by claude-haiku-5-5 on : a language model's rewrite of the original, under its terms