draft-ietf-snmpv2-smi-ds-04.txt   rfc1902.txt 
Internet Draft SMI for SNMPv2 September 1995 Network Working Group SNMPv2 Working Group
Request for Comments: 1902 J. Case
Obsoletes: 1442 SNMP Research, Inc.
Category: Standards Track K. McCloghrie
Cisco Systems, Inc.
M. Rose
Dover Beach Consulting, Inc.
S. Waldbusser
International Network Services
January 1996
Structure of Management Information Structure of Management Information
for Version 2 of the for Version 2 of the
Simple Network Management Protocol (SNMPv2) Simple Network Management Protocol (SNMPv2)
25 September 1995 | Status of this Memo
draft-ietf-snmpv2-smi-ds-04.txt |
Keith McCloghrie
Editor +
Cisco Systems, Inc.
kzm@cisco.com
Status of this Memo -
This document is an Internet-Draft. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its areas, and
its working groups. Note that other groups may also distribute working
documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet- Drafts as reference material
or to cite them other than as ``work in progress.''
To learn the current status of any Internet-Draft, please check the This document specifies an Internet standards track protocol for the
``1id-abstracts.txt'' listing contained in the Internet- Drafts Shadow Internet community, and requests discussion and suggestions for
Directories on ds.internic.net (US East Coast), nic.nordu.net (Europe), improvements. Please refer to the current edition of the "Internet
ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific Rim). Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
1. Introduction 1. Introduction
A management system contains: several (potentially many) nodes, each A management system contains: several (potentially many) nodes, each
with a processing entity, termed an agent, which has access to with a processing entity, termed an agent, which has access to
management instrumentation; at least one management station; and, a management instrumentation; at least one management station; and, a
management protocol, used to convey management information between the management protocol, used to convey management information between
agents and management stations. Operations of the protocol are carried the agents and management stations. Operations of the protocol are
out under an administrative framework which defines authentication, carried out under an administrative framework which defines
authorization, access control, and privacy policies. authentication, authorization, access control, and privacy policies.
Management stations execute management applications which monitor and Management stations execute management applications which monitor and
control managed elements. Managed elements are devices such as hosts, control managed elements. Managed elements are devices such as
routers, terminal servers, etc., which are monitored and controlled via hosts, routers, terminal servers, etc., which are monitored and
access to their management information. controlled via access to their management information.
Management information is viewed as a collection of managed objects, Management information is viewed as a collection of managed objects,
residing in a virtual information store, termed the Management residing in a virtual information store, termed the Management
Information Base (MIB). Collections of related objects are defined in Information Base (MIB). Collections of related objects are defined
MIB modules. These modules are written using an adapted subset of OSI's in MIB modules. These modules are written using an adapted subset of
Abstract Syntax Notation One (ASN.1) [1]. It is the purpose of this OSI's Abstract Syntax Notation One (ASN.1) [1]. It is the purpose of
document, the Structure of Management Information (SMI), to define that this document, the Structure of Management Information (SMI), to
adapted subset, and to assign a set of associated administrative values. define that adapted subset, and to assign a set of associated
administrative values.
The SMI is divided into three parts: module definitions, object The SMI is divided into three parts: module definitions, object
definitions, and, notification definitions. definitions, and, notification definitions.
(1) Module definitions are used when describing information modules. (1) Module definitions are used when describing information modules.
An ASN.1 macro, MODULE-IDENTITY, is used to concisely convey the An ASN.1 macro, MODULE-IDENTITY, is used to concisely convey the
semantics of an information module. semantics of an information module.
(2) Object definitions are used when describing managed objects. An (2) Object definitions are used when describing managed objects. An
ASN.1 macro, OBJECT-TYPE, is used to concisely convey the syntax ASN.1 macro, OBJECT-TYPE, is used to concisely convey the syntax
and semantics of a managed object. and semantics of a managed object.
(3) Notification definitions are used when describing unsolicited (3) Notification definitions are used when describing unsolicited
transmissions of management information. An ASN.1 macro, transmissions of management information. An ASN.1 macro,
NOTIFICATION-TYPE, is used to concisely convey the syntax and NOTIFICATION-TYPE, is used to concisely convey the syntax and
semantics of a notification. semantics of a notification.
1.1. A Note on Terminology 1.1. A Note on Terminology
For the purpose of exposition, the original Internet-standard Network For the purpose of exposition, the original Internet-standard Network
Management Framework, as described in RFCs 1155, 1157, and 1212, is Management Framework, as described in RFCs 1155 (STD 16), 1157 (STD
termed the SNMP version 1 framework (SNMPv1). The current framework is | 15), and 1212 (STD 16), is termed the SNMP version 1 framework
termed the SNMP version 2 framework (SNMPv2), as described in [8]. | (SNMPv1). The current framework is termed the SNMP version 2
framework (SNMPv2).
2. Definitions 2. Definitions
SNMPv2-SMI DEFINITIONS ::= BEGIN SNMPv2-SMI DEFINITIONS ::= BEGIN
-- the path to the root -- the path to the root
org OBJECT IDENTIFIER ::= { iso 3 } org OBJECT IDENTIFIER ::= { iso 3 }
dod OBJECT IDENTIFIER ::= { org 6 } dod OBJECT IDENTIFIER ::= { org 6 }
internet OBJECT IDENTIFIER ::= { dod 1 } internet OBJECT IDENTIFIER ::= { dod 1 }
skipping to change at page 8, line 30 skipping to change at page 5, line 39
timeticks-value timeticks-value
TimeTicks, TimeTicks,
arbitrary-value arbitrary-value
Opaque, Opaque,
big-counter-value big-counter-value
Counter64, Counter64,
unsigned-integer-value -- includes Gauge32 - unsigned-integer-value -- includes Gauge32
Unsigned32 Unsigned32
} }
-- in network-byte order -- in network-byte order
-- (this is a tagged type for historical reasons) -- (this is a tagged type for historical reasons)
IpAddress ::= IpAddress ::=
[APPLICATION 0] [APPLICATION 0]
IMPLICIT OCTET STRING (SIZE (4)) IMPLICIT OCTET STRING (SIZE (4))
-- this wraps -- this wraps
skipping to change at page 10, line 5 skipping to change at page 6, line 34
-- for backward-compatibility only -- for backward-compatibility only
Opaque ::= Opaque ::=
[APPLICATION 4] [APPLICATION 4]
IMPLICIT OCTET STRING IMPLICIT OCTET STRING
-- for counters that wrap in less than one hour with only 32 bits -- for counters that wrap in less than one hour with only 32 bits
Counter64 ::= Counter64 ::=
[APPLICATION 6] [APPLICATION 6]
IMPLICIT INTEGER (0..18446744073709551615) IMPLICIT INTEGER (0..18446744073709551615)
-- definition for objects
OBJECT-TYPE MACRO ::= OBJECT-TYPE MACRO ::=
BEGIN BEGIN
TYPE NOTATION ::= TYPE NOTATION ::=
"SYNTAX" Syntax "SYNTAX" Syntax
UnitsPart UnitsPart
"MAX-ACCESS" Access "MAX-ACCESS" Access
"STATUS" Status "STATUS" Status
"DESCRIPTION" Text "DESCRIPTION" Text
ReferPart ReferPart
skipping to change at page 13, line 4 skipping to change at page 9, line 8
-- definitions of administrative identifiers -- definitions of administrative identifiers
zeroDotZero OBJECT-IDENTITY zeroDotZero OBJECT-IDENTITY
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"A value used for null identifiers." "A value used for null identifiers."
::= { 0 0 } ::= { 0 0 }
END END
3. Information Modules 3. Information Modules
An "information module" is an ASN.1 module defining information relating An "information module" is an ASN.1 module defining information
to network management. relating to network management.
The SMI describes how to use a subset of ASN.1 to define an information The SMI describes how to use a subset of ASN.1 to define an
module. Further, additional restrictions are placed on "standard" information module. Further, additional restrictions are placed on
information modules. It is strongly recommended that "enterprise- "standard" information modules. It is strongly recommended that
specific" information modules also adhere to these restrictions. "enterprise-specific" information modules also adhere to these
restrictions.
Typically, there are three kinds of information modules: Typically, there are three kinds of information modules:
(1) MIB modules, which contain definitions of inter-related managed (1) MIB modules, which contain definitions of inter-related managed
objects, make use of the OBJECT-TYPE and NOTIFICATION-TYPE macros; objects, make use of the OBJECT-TYPE and NOTIFICATION-TYPE macros;
(2) compliance statements for MIB modules, which make use of the (2) compliance statements for MIB modules, which make use of the
MODULE-COMPLIANCE and OBJECT-GROUP macros [2]; and, MODULE-COMPLIANCE and OBJECT-GROUP macros [2]; and,
(3) capability statements for agent implementations which make use of (3) capability statements for agent implementations which make use of
the AGENT-CAPABILITIES macros [2]. the AGENT-CAPABILITIES macros [2].
This classification scheme does not imply a rigid taxonomy. For This classification scheme does not imply a rigid taxonomy. For
example, a "standard" information module will normally include example, a "standard" information module will normally include
definitions of managed objects and a compliance statement. Similarly, definitions of managed objects and a compliance statement.
an "enterprise-specific" information module might include definitions of Similarly, an "enterprise-specific" information module might include
managed objects and a capability statement. Of course, a "standard" definitions of managed objects and a capability statement. Of
information module may not contain capability statements. course, a "standard" information module may not contain capability
statements.
The constructs of ASN.1 allowed in SNMPv2 information modules include: The constructs of ASN.1 allowed in SNMPv2 information modules
the IMPORTS clause, value definitions for OBJECT IDENTIFIERs, type include: the IMPORTS clause, value definitions for OBJECT
definitions for SEQUENCEs (with restrictions), ASN.1 type assignments of IDENTIFIERs, type definitions for SEQUENCEs (with restrictions),
the restricted ASN.1 types allowed in SNMPv2, and instances of ASN.1 ASN.1 type assignments of the restricted ASN.1 types allowed in
macros defined in this document and in other documents [2, 3] of the SNMPv2, and instances of ASN.1 macros defined in this document and in
SNMPv2 framework. Additional ASN.1 macros may not be defined in SNMPv2 other documents [2, 3] of the SNMPv2 framework. Additional ASN.1
information modules. macros may not be defined in SNMPv2 information modules.
The names of all standard information modules must be unique (but The names of all standard information modules must be unique (but
different versions of the same information module should have the same different versions of the same information module should have the
name). Developers of enterprise information modules are encouraged to same name). Developers of enterprise information modules are
choose names for their information modules that will have a low encouraged to choose names for their information modules that will
probability of colliding with standard or other enterprise information have a low probability of colliding with standard or other enterprise
modules. An information module may not use the ASN.1 construct of information modules. An information module may not use the ASN.1
placing an object identifier value between the module name and the construct of placing an object identifier value between the module
"DEFINITIONS" keyword. name and the "DEFINITIONS" keyword.
All information modules start with exactly one invocation of the All information modules start with exactly one invocation of the
MODULE-IDENTITY macro, which provides contact information as well as MODULE-IDENTITY macro, which provides contact information as well as
revision history to distinguish between versions of the same information revision history to distinguish between versions of the same
module. This invocation must appear immediately after any IMPORTs information module. This invocation must appear immediately after
statements. any IMPORTs statements.
3.1. Macro Invocation 3.1. Macro Invocation
Within an information module, each macro invocation appears as: Within an information module, each macro invocation appears as:
<descriptor> <macro> <clauses> ::= <value> <descriptor> <macro> <clauses> ::= <value>
where <descriptor> corresponds to an ASN.1 identifier, <macro> names the where <descriptor> corresponds to an ASN.1 identifier, <macro> names
macro being invoked, and <clauses> and <value> depend on the definition the macro being invoked, and <clauses> and <value> depend on the
of the macro. (Note that this definition of a descriptor applies to all definition of the macro. (Note that this definition of a descriptor
macros defined in this memo and in [2].) applies to all macros defined in this memo and in [2].)
For the purposes of this specification, an ASN.1 identifier consists of For the purposes of this specification, an ASN.1 identifier consists
one or more letters or digits, and its initial character must be a of one or more letters or digits, and its initial character must be a
lower-case letter. (Note that hyphens are not allowed by this lower-case letter. (Note that hyphens are not allowed by this
specification, even though hyphen is allowed by [1]. This restriction specification, even though hyphen is allowed by [1]. This
enables arithmetic expressions in languages which use the minus sign to restriction enables arithmetic expressions in languages which use the
reference these descriptors without ambiguity.) minus sign to reference these descriptors without ambiguity.)
For all descriptors appearing in an information module, the descriptor For all descriptors appearing in an information module, the
shall be unique and mnemonic, and shall not exceed 64 characters in descriptor shall be unique and mnemonic, and shall not exceed 64
length. (However, descriptors longer than 32 characters are not characters in length. (However, descriptors longer than 32
recommended.) This promotes a common language for humans to use when characters are not recommended.) This promotes a common language for
discussing the information module and also facilitates simple table humans to use when discussing the information module and also
mappings for user-interfaces. facilitates simple table mappings for user-interfaces.
The set of descriptors defined in all "standard" information modules The set of descriptors defined in all "standard" information modules
shall be unique. shall be unique.
Finally, by convention, if the descriptor refers to an object with a Finally, by convention, if the descriptor refers to an object with a
SYNTAX clause value of either Counter32 or Counter64, then the SYNTAX clause value of either Counter32 or Counter64, then the
descriptor used for the object should denote plurality. descriptor used for the object should denote plurality.
3.1.1. Textual Clauses 3.1.1. Textual Clauses
Some clauses in a macro invocation may take a textual value (e.g., the Some clauses in a macro invocation may take a textual value (e.g.,
DESCRIPTION clause). Note that, in order to conform to the ASN.1 the DESCRIPTION clause). Note that, in order to conform to the ASN.1
syntax, the entire value of these clauses must be enclosed in double syntax, the entire value of these clauses must be enclosed in double
quotation marks, and therefore cannot itself contain double quotation quotation marks, and therefore cannot itself contain double quotation
marks, although the value may be multi-line. marks, although the value may be multi-line.
3.2. IMPORTing Symbols 3.2. IMPORTing Symbols
To reference an external object, the IMPORTS statement must be used to To reference an external object, the IMPORTS statement must be used
identify both the descriptor and the module in which the descriptor is to identify both the descriptor and the module in which the
defined, where the module is identified by its ASN.1 module name. descriptor is defined, where the module is identified by its ASN.1
module name.
Note that when symbols from "enterprise-specific" information modules Note that when symbols from "enterprise-specific" information modules
are referenced (e.g., a descriptor), there is the possibility of are referenced (e.g., a descriptor), there is the possibility of
collision. As such, if different objects with the same descriptor are collision. As such, if different objects with the same descriptor
IMPORTed, then this ambiguity is resolved by prefixing the descriptor are IMPORTed, then this ambiguity is resolved by prefixing the
with the name of the information module and a dot ("."), i.e., descriptor with the name of the information module and a dot ("."),
i.e.,
"module.descriptor" "module.descriptor"
(All descriptors must be unique within any information module.) (All descriptors must be unique within any information module.)
Of course, this notation can be used even when there is no collision Of course, this notation can be used even when there is no collision
when IMPORTing symbols. when IMPORTing symbols.
Finally, the IMPORTS statement may not be used to import an ASN.1 named Finally, the IMPORTS statement may not be used to import an ASN.1
type which corresponds to either the SEQUENCE or SEQUENCE OF type. named type which corresponds to either the SEQUENCE or SEQUENCE OF
type.
3.3. Exporting Symbols 3.3. Exporting Symbols
The ASN.1 EXPORTS statement is not allowed in SNMPv2 information The ASN.1 EXPORTS statement is not allowed in SNMPv2 information
modules. All items defined in an information module are automatically modules. All items defined in an information module are
exported. automatically exported.
3.4. ASN.1 Comments 3.4. ASN.1 Comments
Comments in ASN.1 commence with a pair of adjacent hyphens and end with Comments in ASN.1 commence with a pair of adjacent hyphens and end
the next pair of adjacent hyphens or at the end of the line, whichever with the next pair of adjacent hyphens or at the end of the line,
occurs first. whichever occurs first.
3.5. OBJECT IDENTIFIER values 3.5. OBJECT IDENTIFIER values
An OBJECT IDENTIFIER value is an ordered list of non-negative numbers. An OBJECT IDENTIFIER value is an ordered list of non-negative
For the SNMPv2 framework, each number in the list is referred to as a numbers. For the SNMPv2 framework, each number in the list is
sub-identifier, there are at most 128 sub-identifiers in a value, and referred to as a sub-identifier, there are at most 128 sub-
each sub-identifier has a maximum value of 2^32-1 (4294967295 decimal). identifiers in a value, and each sub-identifier has a maximum value
All OBJECT IDENTIFIER values have at least two sub-identifiers, where of 2^32-1 (4294967295 decimal). All OBJECT IDENTIFIER values have at
the value of the first sub-identifier is one of the following well-known least two sub-identifiers, where the value of the first sub-
names: identifier is one of the following well-known names:
Value Name Value Name
0 ccitt 0 ccitt
1 iso 1 iso
2 joint-iso-ccitt 2 joint-iso-ccitt
4. Naming Hierarchy 4. Naming Hierarchy
The root of the subtree administered by the Internet Assigned Numbers The root of the subtree administered by the Internet Assigned Numbers
Authority (IANA) for the Internet is: Authority (IANA) for the Internet is:
internet OBJECT IDENTIFIER ::= { iso 3 6 1 } internet OBJECT IDENTIFIER ::= { iso 3 6 1 }
That is, the Internet subtree of OBJECT IDENTIFIERs starts with the That is, the Internet subtree of OBJECT IDENTIFIERs starts with the
prefix: prefix:
1.3.6.1. 1.3.6.1.
Several branches underneath this subtree are used for network Several branches underneath this subtree are used for network
management: management:
mgmt OBJECT IDENTIFIER ::= { internet 2 } mgmt OBJECT IDENTIFIER ::= { internet 2 }
experimental OBJECT IDENTIFIER ::= { internet 3 } experimental OBJECT IDENTIFIER ::= { internet 3 }
private OBJECT IDENTIFIER ::= { internet 4 } private OBJECT IDENTIFIER ::= { internet 4 }
enterprises OBJECT IDENTIFIER ::= { private 1 } enterprises OBJECT IDENTIFIER ::= { private 1 }
However, the SMI does not prohibit the definition of objects in other However, the SMI does not prohibit the definition of objects in other
portions of the object tree. portions of the object tree.
The mgmt(2) subtree is used to identify "standard" objects. The mgmt(2) subtree is used to identify "standard" objects.
The experimental(3) subtree is used to identify objects being designed The experimental(3) subtree is used to identify objects being
by working groups of the IETF. If an information module produced by a designed by working groups of the IETF. If an information module
working group becomes a "standard" information module, then at the very produced by a working group becomes a "standard" information module,
beginning of its entry onto the Internet standards track, the objects then at the very beginning of its entry onto the Internet standards
are moved under the mgmt(2) subtree. track, the objects are moved under the mgmt(2) subtree.
The private(4) subtree is used to identify objects defined unilaterally. The private(4) subtree is used to identify objects defined
The enterprises(1) subtree beneath private is used, among other things, unilaterally. The enterprises(1) subtree beneath private is used,
to permit providers of networking subsystems to register models of their among other things, to permit providers of networking subsystems to
products. register models of their products.
5. Mapping of the MODULE-IDENTITY macro 5. Mapping of the MODULE-IDENTITY macro
The MODULE-IDENTITY macro is used to provide contact and revision The MODULE-IDENTITY macro is used to provide contact and revision
history for each information module. It must appear exactly once in history for each information module. It must appear exactly once in
every information module. It should be noted that the expansion of the every information module. It should be noted that the expansion of
MODULE-IDENTITY macro is something which conceptually happens during the MODULE-IDENTITY macro is something which conceptually happens
implementation and not during run-time. during implementation and not during run-time.
Note that reference in an IMPORTS clause or in clauses of SNMPv2 macros Note that reference in an IMPORTS clause or in clauses of SNMPv2
to an information module is NOT through the use of the 'descriptor' of a macros to an information module is NOT through the use of the
MODULE-IDENTITY macro; rather, an information module is referenced 'descriptor' of a MODULE-IDENTITY macro; rather, an information
through specifying its module name. module is referenced through specifying its module name.
5.1. Mapping of the LAST-UPDATED clause 5.1. Mapping of the LAST-UPDATED clause
The LAST-UPDATED clause, which must be present, contains the date and The LAST-UPDATED clause, which must be present, contains the date and
time that this information module was last edited. The date and time time that this information module was last edited. The date and time
are represented in UTC Time format (see Appendix B). are represented in UTC Time format (see Appendix B).
5.2. Mapping of the ORGANIZATION clause 5.2. Mapping of the ORGANIZATION clause
The ORGANIZATION clause, which must be present, contains a textual The ORGANIZATION clause, which must be present, contains a textual
description of the organization under whose auspices this information description of the organization under whose auspices this information
module was developed. module was developed.
5.3. Mapping of the CONTACT-INFO clause 5.3. Mapping of the CONTACT-INFO clause
The CONTACT-INFO clause, which must be present, contains the name, The CONTACT-INFO clause, which must be present, contains the name,
postal address, telephone number, and electronic mail address of the postal address, telephone number, and electronic mail address of the
person to whom technical queries concerning this information module person to whom technical queries concerning this information module
should be sent. should be sent.
5.4. Mapping of the DESCRIPTION clause 5.4. Mapping of the DESCRIPTION clause
The DESCRIPTION clause, which must be present, contains a high-level The DESCRIPTION clause, which must be present, contains a high-level
textual description of the contents of this information module. textual description of the contents of this information module.
5.5. Mapping of the REVISION clause 5.5. Mapping of the REVISION clause
The REVISION clause, which need not be present, is repeatedly used to The REVISION clause, which need not be present, is repeatedly used to
describe the revisions (including the initial version) made to this describe the revisions (including the initial version) made to this
information module, in reverse chronological order (i.e., most recent information module, in reverse chronological order (i.e., most recent
first). Each instance of this clause contains the date and time of the first). Each instance of this clause contains the date and time of
revision. The date and time are represented in UTC Time format (see the revision. The date and time are represented in UTC Time format
Appendix B). (see Appendix B).
5.5.1. Mapping of the DESCRIPTION sub-clause 5.5.1. Mapping of the DESCRIPTION sub-clause
The DESCRIPTION clause, which must be present for each REVISION clause, The DESCRIPTION clause, which must be present for each REVISION
contains a high-level textual description of the revision identified in clause, contains a high-level textual description of the revision
that REVISION clause. identified in that REVISION clause.
5.6. Mapping of the MODULE-IDENTITY value 5.6. Mapping of the MODULE-IDENTITY value
The value of an invocation of the MODULE-IDENTITY macro is an OBJECT The value of an invocation of the MODULE-IDENTITY macro is an OBJECT
IDENTIFIER. As such, this value may be authoritatively used when IDENTIFIER. As such, this value may be authoritatively used when
specifying an OBJECT IDENTIFIER value to refer to the information module specifying an OBJECT IDENTIFIER value to refer to the information
containing the invocation. module containing the invocation.
5.7. Usage Example 5.7. Usage Example
Consider how a skeletal MIB module might be constructed: e.g., Consider how a skeletal MIB module might be constructed: e.g.,
FIZBIN-MIB DEFINITIONS ::= BEGIN FIZBIN-MIB DEFINITIONS ::= BEGIN
IMPORTS IMPORTS
MODULE-IDENTITY, OBJECT-TYPE, experimental MODULE-IDENTITY, OBJECT-TYPE, experimental
FROM SNMPv2-SMI; FROM SNMPv2-SMI;
fizbin MODULE-IDENTITY fizbin MODULE-IDENTITY
LAST-UPDATED "9505241811Z" LAST-UPDATED "9505241811Z"
ORGANIZATION "IETF SNMPv2 Working Group" ORGANIZATION "IETF SNMPv2 Working Group"
skipping to change at page 21, line 6 skipping to change at page 15, line 6
"The latest version of this MIB module." "The latest version of this MIB module."
REVISION "9210070433Z" REVISION "9210070433Z"
DESCRIPTION DESCRIPTION
"The initial version of this MIB module." "The initial version of this MIB module."
-- contact IANA for actual number -- contact IANA for actual number
::= { experimental xx } ::= { experimental xx }
END END
6. Mapping of the OBJECT-IDENTITY macro 6. Mapping of the OBJECT-IDENTITY macro
The OBJECT-IDENTITY macro is used to define information about an OBJECT The OBJECT-IDENTITY macro is used to define information about an
IDENTIFIER assignment. All administrative OBJECT IDENTIFIER assignments OBJECT IDENTIFIER assignment. All administrative OBJECT IDENTIFIER
which define a type identification value (see AutonomousType, a textual assignments which define a type identification value (see
convention defined in [3]) should be defined via the OBJECT-IDENTITY AutonomousType, a textual convention defined in [3]) should be
macro. It should be noted that the expansion of the OBJECT-IDENTITY defined via the OBJECT-IDENTITY macro. It should be noted that the
macro is something which conceptually happens during implementation and expansion of the OBJECT-IDENTITY macro is something which
not during run-time. conceptually happens during implementation and not during run-time.
6.1. Mapping of the STATUS clause 6.1. Mapping of the STATUS clause
The STATUS clause, which must be present, indicates whether this The STATUS clause, which must be present, indicates whether this
definition is current or historic. definition is current or historic.
The values "current", and "obsolete" are self-explanatory. The The values "current", and "obsolete" are self-explanatory. The
"deprecated" value indicates that the definition is obsolete, but that "deprecated" value indicates that the definition is obsolete, but
an implementor may wish to support it to foster interoperability with that an implementor may wish to support it to foster interoperability
older implementations. with older implementations.
6.2. Mapping of the DESCRIPTION clause 6.2. Mapping of the DESCRIPTION clause
The DESCRIPTION clause, which must be present, contains a textual The DESCRIPTION clause, which must be present, contains a textual
description of the object assignment. description of the object assignment.
6.3. Mapping of the REFERENCE clause 6.3. Mapping of the REFERENCE clause
The REFERENCE clause, which need not be present, contains a textual The REFERENCE clause, which need not be present, contains a textual
cross-reference to an object assignment defined in some other cross-reference to an object assignment defined in some other
information module. information module.
6.4. Mapping of the OBJECT-IDENTITY value 6.4. Mapping of the OBJECT-IDENTITY value
The value of an invocation of the OBJECT-IDENTITY macro is an OBJECT The value of an invocation of the OBJECT-IDENTITY macro is an OBJECT
IDENTIFIER. IDENTIFIER.
6.5. Usage Example 6.5. Usage Example
Consider how an OBJECT IDENTIFIER assignment might be made: e.g., Consider how an OBJECT IDENTIFIER assignment might be made: e.g.,
fizbin69 OBJECT-IDENTITY fizbin69 OBJECT-IDENTITY
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"The authoritative identity of the Fizbin 69 chipset." "The authoritative identity of the Fizbin 69 chipset."
::= { fizbinChipSets 1 } ::= { fizbinChipSets 1 }
7. Mapping of the OBJECT-TYPE macro 7. Mapping of the OBJECT-TYPE macro
The OBJECT-TYPE macro is used to define a type of managed object. It The OBJECT-TYPE macro is used to define a type of managed object. It
should be noted that the expansion of the OBJECT-TYPE macro is something should be noted that the expansion of the OBJECT-TYPE macro is
which conceptually happens during implementation and not during run- something which conceptually happens during implementation and not
time. during run-time.
For leaf objects which are not columnar objects (i.e., not contained For leaf objects which are not columnar objects (i.e., not contained
within a conceptual table), instances of the object are identified by within a conceptual table), instances of the object are identified by
appending a sub-identifier of zero to the name of that object. appending a sub-identifier of zero to the name of that object.
Otherwise, the INDEX clause of the conceptual row object superior to a Otherwise, the INDEX clause of the conceptual row object superior to
columnar object defines instance identification information. a columnar object defines instance identification information.
7.1. Mapping of the SYNTAX clause 7.1. Mapping of the SYNTAX clause
The SYNTAX clause, which must be present, defines the abstract data The SYNTAX clause, which must be present, defines the abstract data
structure corresponding to that object. The data structure must be one structure corresponding to that object. The data structure must be
of the following: a base type, the BITS construct, or a textual one of the following: a base type, the BITS construct, or a textual
convention. (SEQUENCE OF and SEQUENCE are also possible for conceptual convention. (SEQUENCE OF and SEQUENCE are also possible for
tables, see section 7.1.12). The base types are those defined in the conceptual tables, see section 7.1.12). The base types are those
ObjectSyntax CHOICE. A textual convention is a newly-defined type defined in the ObjectSyntax CHOICE. A textual convention is a
defined as a sub-type of a base type [3]. newly-defined type defined as a sub-type of a base type [3].
A extended subset of the full capabilities of ASN.1 sub-typing is A extended subset of the full capabilities of ASN.1 sub-typing is
allowed, as appropriate to the underingly ASN.1 type. Any such allowed, as appropriate to the underingly ASN.1 type. Any such
restriction on size, range, enumerations or repertoire specified in this restriction on size, range, enumerations or repertoire specified in
clause represents the maximal level of support which makes "protocol this clause represents the maximal level of support which makes
sense". Restrictions on sub-typing are specified in detail in Section 9 "protocol sense". Restrictions on sub-typing are specified in detail
and Appendix C of this memo. in Section 9 and Appendix C of this memo.
The semantics of ObjectSyntax are now described. The semantics of ObjectSyntax are now described.
7.1.1. Integer32 and INTEGER 7.1.1. Integer32 and INTEGER
The Integer32 type represents integer-valued information between -2^31 The Integer32 type represents integer-valued information between
and 2^31-1 inclusive (-2147483648 to 2147483647 decimal). This type is -2^31 and 2^31-1 inclusive (-2147483648 to 2147483647 decimal). This
indistinguishable from the INTEGER type. Both the INTEGER and Integer32 type is indistinguishable from the INTEGER type. Both the INTEGER
types may be sub-typed to be more constrained than the Integer32 type. and Integer32 types may be sub-typed to be more constrained than the
Integer32 type.
The INTEGER type may also be used to represent integer-valued The INTEGER type may also be used to represent integer-valued
information as named-number enumerations. In this case, only those information as named-number enumerations. In this case, only those
named-numbers so enumerated may be present as a value. Note that named-numbers so enumerated may be present as a value. Note that
although it is recommended that enumerated values start at 1 and be although it is recommended that enumerated values start at 1 and be
numbered contiguously, any valid value for Integer32 is allowed for an numbered contiguously, any valid value for Integer32 is allowed for
enumerated value and, further, enumerated values needn't be contiguously an enumerated value and, further, enumerated values needn't be
assigned. contiguously assigned.
Finally, a label for a named-number enumeration must consist of one or Finally, a label for a named-number enumeration must consist of one
more letters or digits (no hyphens), up to a maximum of 64 characters, or more letters or digits (no hyphens), up to a maximum of 64
and the initial character must be a lower-case letter. (However, labels characters, and the initial character must be a lower-case letter.
longer than 32 characters are not recommended.) (However, labels longer than 32 characters are not recommended.)
7.1.2. OCTET STRING 7.1.2. OCTET STRING
The OCTET STRING type represents arbitrary binary or textual data. The OCTET STRING type represents arbitrary binary or textual data.
Although there is no SMI-specified size limitation for this type, MIB Although there is no SMI-specified size limitation for this type, MIB
designers should realize that there may be implementation and designers should realize that there may be implementation and
interoperability limitations for sizes in excess of 255 octets. interoperability limitations for sizes in excess of 255 octets.
7.1.3. OBJECT IDENTIFIER 7.1.3. OBJECT IDENTIFIER
The OBJECT IDENTIFIER type represents administratively assigned names. The OBJECT IDENTIFIER type represents administratively assigned
Any instance of this type may have at most 128 sub-identifiers. names. Any instance of this type may have at most 128 sub-
Further, each sub-identifier must not exceed the value 2^32-1 identifiers. Further, each sub-identifier must not exceed the value
(4294967295 decimal). 2^32-1 (4294967295 decimal).
7.1.4. The BITS construct 7.1.4. The BITS construct
The BITS construct represents an enumeration of named bits. This The BITS construct represents an enumeration of named bits. This
collection is assigned non-negative, contiguous values, starting at collection is assigned non-negative, contiguous values, starting at
zero. Only those named-bits so enumerated may be present in a value. zero. Only those named-bits so enumerated may be present in a value.
(Thus, enumerations must be assigned to consecutive bits; however, see (Thus, enumerations must be assigned to consecutive bits; however,
Section 9 for refinements of an object with this syntax.) see Section 9 for refinements of an object with this syntax.)
Although there is no SMI-specified limitation on the number of Although there is no SMI-specified limitation on the number of
enumerations (and therefore on the length of a value), MIB designers enumerations (and therefore on the length of a value), MIB designers
should realize that there may be implementation and interoperability should realize that there may be implementation and interoperability
limitations for sizes in excess of 128 bits. limitations for sizes in excess of 128 bits.
Finally, a label for a named-number enumeration must consist of one
or more letters or digits (no hyphens), up to a maximum of 64
characters, and the initial character must be a lower-case letter.
(However, labels longer than 32 characters are not recommended.)
Finally, a label for a named-number enumeration must consist of one or
more letters or digits (no hyphens), up to a maximum of 64 characters,
and the initial character must be a lower-case letter. (However, labels
longer than 32 characters are not recommended.)
7.1.5. IpAddress 7.1.5. IpAddress
The IpAddress type represents a 32-bit internet address. It is The IpAddress type represents a 32-bit internet address. It is
represented as an OCTET STRING of length 4, in network byte-order. represented as an OCTET STRING of length 4, in network byte-order.
Note that the IpAddress type is a tagged type for historical reasons. Note that the IpAddress type is a tagged type for historical reasons.
Network addresses should be represented using an invocation of the Network addresses should be represented using an invocation of the
TEXTUAL-CONVENTION macro [3]. TEXTUAL-CONVENTION macro [3].
7.1.6. Counter32 7.1.6. Counter32
The Counter32 type represents a non-negative integer which monotonically The Counter32 type represents a non-negative integer which
increases until it reaches a maximum value of 2^32-1 (4294967295 monotonically increases until it reaches a maximum value of 2^32-1
decimal), when it wraps around and starts increasing again from zero. (4294967295 decimal), when it wraps around and starts increasing
again from zero.
Counters have no defined "initial" value, and thus, a single value of a Counters have no defined "initial" value, and thus, a single value of
Counter has (in general) no information content. Discontinuities in the a Counter has (in general) no information content. Discontinuities
monotonically increasing value normally occur at re-initialization of in the monotonically increasing value normally occur at re-
the management system, and at other times as specified in the initialization of the management system, and at other times as
description of an object-type using this ASN.1 type. If such other specified in the description of an object-type using this ASN.1 type.
times can occur, for example, the creation of an object instance at If such other times can occur, for example, the creation of an object
times other than re-initialization, then a corresponding object should instance at times other than re-initialization, then a corresponding
be defined with a SYNTAX clause value of TimeStamp (a textual convention object should be defined with a SYNTAX clause value of TimeStamp (a
defined in [3]) indicating the time of the last discontinuity. textual convention defined in [3]) indicating the time of the last
discontinuity.
The value of the MAX-ACCESS clause for objects with a SYNTAX clause The value of the MAX-ACCESS clause for objects with a SYNTAX clause
value of Counter32 is either "read-only" or "accessible-for-notify". value of Counter32 is either "read-only" or "accessible-for-notify".
A DEFVAL clause is not allowed for objects with a SYNTAX clause value of A DEFVAL clause is not allowed for objects with a SYNTAX clause value
Counter32. of Counter32.
7.1.7. Gauge32 7.1.7. Gauge32
The Gauge32 type represents a non-negative integer, which may increase The Gauge32 type represents a non-negative integer, which may
or decrease, but shall never exceed a maximum value. The maximum value increase or decrease, but shall never exceed a maximum value. The
can not be greater than 2^32-1 (4294967295 decimal). The value of a maximum value can not be greater than 2^32-1 (4294967295 decimal).
Gauge has its maximum value whenever the information being modeled is The value of a Gauge has its maximum value whenever the information
greater or equal to that maximum value; if the information being modeled being modeled is greater or equal to that maximum value; if the
subsequently decreases below the maximum value, the Gauge also information being modeled subsequently decreases below the maximum
decreases. value, the Gauge also decreases.
7.1.8. TimeTicks 7.1.8. TimeTicks
The TimeTicks type represents a non-negative integer which represents The TimeTicks type represents a non-negative integer which represents
the time, modulo 2^32 (4294967296 decimal), in hundredths of a second the time, modulo 2^32 (4294967296 decimal), in hundredths of a second
between two epochs. When objects are defined which use this ASN.1 type, between two epochs. When objects are defined which use this ASN.1
the description of the object identifies both of the reference epochs. type, the description of the object identifies both of the reference
epochs.
For example, [3] defines the TimeStamp textual convention which is based For example, [3] defines the TimeStamp textual convention which is
on the TimeTicks type. With a TimeStamp, the first reference epoch is based on the TimeTicks type. With a TimeStamp, the first reference
defined as the time when sysUpTime [5] was zero, and the second epoch is defined as the time when sysUpTime [5] was zero, and the
reference epoch is defined as the current value of sysUpTime. second reference epoch is defined as the current value of sysUpTime.
The TimeTicks type may not be sub-typed. The TimeTicks type may not be sub-typed.
7.1.9. Opaque 7.1.9. Opaque
The Opaque type is provided solely for backward-compatibility, and shall The Opaque type is provided solely for backward-compatibility, and
not be used for newly-defined object types. shall not be used for newly-defined object types.
The Opaque type supports the capability to pass arbitrary ASN.1 syntax. The Opaque type supports the capability to pass arbitrary ASN.1
A value is encoded using the ASN.1 Basic Encoding Rules [4] into a syntax. A value is encoded using the ASN.1 Basic Encoding Rules [4]
string of octets. This, in turn, is encoded as an OCTET STRING, in into a string of octets. This, in turn, is encoded as an OCTET
effect "double-wrapping" the original ASN.1 value. STRING, in effect "double-wrapping" the original ASN.1 value.
Note that a conforming implementation need only be able to accept and Note that a conforming implementation need only be able to accept and
recognize opaquely-encoded data. It need not be able to unwrap the data recognize opaquely-encoded data. It need not be able to unwrap the
and then interpret its contents. data and then interpret its contents.
A requirement on "standard" MIB modules is that no object may have a A requirement on "standard" MIB modules is that no object may have a
SYNTAX clause value of Opaque. SYNTAX clause value of Opaque.
7.1.10. Counter64 7.1.10. Counter64
The Counter64 type represents a non-negative integer which monotonically The Counter64 type represents a non-negative integer which
increases until it reaches a maximum value of 2^64-1 monotonically increases until it reaches a maximum value of 2^64-1
(18446744073709551615 decimal), when it wraps around and starts (18446744073709551615 decimal), when it wraps around and starts
increasing again from zero. increasing again from zero.
Counters have no defined "initial" value, and thus, a single value of a Counters have no defined "initial" value, and thus, a single value of
Counter has (in general) no information content. Discontinuities in the a Counter has (in general) no information content. Discontinuities
monotonically increasing value normally occur at re-initialization of in the monotonically increasing value normally occur at re-
the management system, and at other times as specified in the initialization of the management system, and at other times as
description of an object-type using this ASN.1 type. If such other specified in the description of an object-type using this ASN.1 type.
times can occur, for example, the creation of an object instance at If such other times can occur, for example, the creation of an object
times other than re-initialization, then a corresponding object should instance at times other than re-initialization, then a corresponding
be defined with a SYNTAX clause value of TimeStamp (a textual convention object should be defined with a SYNTAX clause value of TimeStamp (a
defined in [3]) indicating the time of the last discontinuity. textual convention defined in [3]) indicating the time of the last
discontinuity.
The value of the MAX-ACCESS clause for objects with a SYNTAX clause The value of the MAX-ACCESS clause for objects with a SYNTAX clause
value of Counter64 is either "read-only" or "accessible-for-notify". value of Counter64 is either "read-only" or "accessible-for-notify".
A requirement on "standard" MIB modules is that the Counter64 type may A requirement on "standard" MIB modules is that the Counter64 type
be used only if the information being modeled would wrap in less than may be used only if the information being modeled would wrap in less
one hour if the Counter32 type was used instead. than one hour if the Counter32 type was used instead.
A DEFVAL clause is not allowed for objects with a SYNTAX clause value of A DEFVAL clause is not allowed for objects with a SYNTAX clause value
Counter64. of Counter64.
7.1.11. Unsigned32 7.1.11. Unsigned32
The Unsigned32 type represents integer-valued information between 0 and The Unsigned32 type represents integer-valued information between 0
2^32-1 inclusive (0 to 4294967295 decimal). and 2^32-1 inclusive (0 to 4294967295 decimal).
7.1.12. Conceptual Tables 7.1.12. Conceptual Tables
Management operations apply exclusively to scalar objects. However, it Management operations apply exclusively to scalar objects. However,
is sometimes convenient for developers of management applications to it is sometimes convenient for developers of management applications
impose an imaginary, tabular structure on an ordered collection of to impose an imaginary, tabular structure on an ordered collection of
objects within the MIB. Each such conceptual table contains zero or objects within the MIB. Each such conceptual table contains zero or
more rows, and each row may contain one or more scalar objects, termed more rows, and each row may contain one or more scalar objects,
columnar objects. This conceptualization is formalized by using the termed columnar objects. This conceptualization is formalized by
OBJECT-TYPE macro to define both an object which corresponds to a table using the OBJECT-TYPE macro to define both an object which
and an object which corresponds to a row in that table. A conceptual corresponds to a table and an object which corresponds to a row in
table has SYNTAX of the form: that table. A conceptual table has SYNTAX of the form:
SEQUENCE OF <EntryType> SEQUENCE OF <EntryType>
where <EntryType> refers to the SEQUENCE type of its subordinate where <EntryType> refers to the SEQUENCE type of its subordinate
conceptual row. A conceptual row has SYNTAX of the form: conceptual row. A conceptual row has SYNTAX of the form:
<EntryType> <EntryType>
where <EntryType> is a SEQUENCE type defined as follows: where <EntryType> is a SEQUENCE type defined as follows:
<EntryType> ::= SEQUENCE { <type1>, ... , <typeN> } <EntryType> ::= SEQUENCE { <type1>, ... , <typeN> }
where there is one <type> for each subordinate object, and each <type> where there is one <type> for each subordinate object, and each
is of the form: <type> is of the form:
<descriptor> <syntax> <descriptor> <syntax>
where <descriptor> is the descriptor naming a subordinate object, and where <descriptor> is the descriptor naming a subordinate object, and
<syntax> has the value of that subordinate object's SYNTAX clause, <syntax> has the value of that subordinate object's SYNTAX clause,
normally omitting the sub-typing information. Further, these ASN.1 normally omitting the sub-typing information. Further, these ASN.1
types are always present (the DEFAULT and OPTIONAL clauses are types are always present (the DEFAULT and OPTIONAL clauses are
disallowed in the SEQUENCE definition). The MAX-ACCESS clause for disallowed in the SEQUENCE definition). The MAX-ACCESS clause for
conceptual tables and rows is "not-accessible". conceptual tables and rows is "not-accessible".
7.1.12.1. Creation and Deletion of Conceptual Rows 7.1.12.1. Creation and Deletion of Conceptual Rows
For newly-defined conceptual rows which allow the creation of new object For newly-defined conceptual rows which allow the creation of new
instances and/or the deletion of existing object instances, there should object instances and/or the deletion of existing object instances,
be one columnar object with a SYNTAX clause value of RowStatus (a there should be one columnar object with a SYNTAX clause value of
textual convention defined in [3]) and a MAX-ACCESS clause value of RowStatus (a textual convention defined in [3]) and a MAX-ACCESS
read-create. By convention, this is termed the status column for the clause value of read-create. By convention, this is termed the
conceptual row. status column for the conceptual row.
7.2. Mapping of the UNITS clause 7.2. Mapping of the UNITS clause
This UNITS clause, which need not be present, contains a textual This UNITS clause, which need not be present, contains a textual
definition of the units associated with that object. definition of the units associated with that object.
7.3. Mapping of the MAX-ACCESS clause 7.3. Mapping of the MAX-ACCESS clause
The MAX-ACCESS clause, which must be present, defines whether it makes The MAX-ACCESS clause, which must be present, defines whether it
"protocol sense" to read, write and/or create an instance of the object, makes "protocol sense" to read, write and/or create an instance of
or to include its value in a notification. This is the maximal level of the object, or to include its value in a notification. This is the
access for the object. (This maximal level of access is independent of maximal level of access for the object. (This maximal level of
any administrative authorization policy.) access is independent of any administrative authorization policy.)
The value "read-write" indicates that read and write access make The value "read-write" indicates that read and write access make
"protocol sense", but create does not. The value "read-create" "protocol sense", but create does not. The value "read-create"
indicates that read, write and create access make "protocol sense". The indicates that read, write and create access make "protocol sense".
value "not-accessible" indicates an auxiliary object (see Section 7.7). The value "not-accessible" indicates an auxiliary object (see Section
The value "accessible-for-notify" indicates an object which is 7.7). The value "accessible-for-notify" indicates an object which is
accessible only via a notification (e.g., snmpTrapOID [5]). accessible only via a notification (e.g., snmpTrapOID [5]).
These values are ordered, from least to greatest: "not-accessible", These values are ordered, from least to greatest: "not-accessible",
"accessible-for-notify", "read-only", "read-write", "read-create". "accessible-for-notify", "read-only", "read-write", "read-create".
If any columnar object in a conceptual row has "read-create" as its If any columnar object in a conceptual row has "read-create" as its
maximal level of access, then no other columnar object of the same maximal level of access, then no other columnar object of the same
conceptual row may have a maximal access of "read-write". (Note that conceptual row may have a maximal access of "read-write". (Note that
"read-create" is a superset of "read-write".) "read-create" is a superset of "read-write".)
7.4. Mapping of the STATUS clause 7.4. Mapping of the STATUS clause
The STATUS clause, which must be present, indicates whether this The STATUS clause, which must be present, indicates whether this
definition is current or historic. definition is current or historic.
The values "current", and "obsolete" are self-explanatory. The The values "current", and "obsolete" are self-explanatory. The
"deprecated" value indicates that the definition is obsolete, but that "deprecated" value indicates that the definition is obsolete, but
an implementor may wish to support that object to foster that an implementor may wish to support that object to foster
interoperability with older implementations. interoperability with older implementations.
7.5. Mapping of the DESCRIPTION clause 7.5. Mapping of the DESCRIPTION clause
The DESCRIPTION clause, which must be present, contains a textual The DESCRIPTION clause, which must be present, contains a textual
definition of that object which provides all semantic definitions definition of that object which provides all semantic definitions
necessary for implementation, and should embody any information which necessary for implementation, and should embody any information which
would otherwise be communicated in any ASN.1 commentary annotations would otherwise be communicated in any ASN.1 commentary annotations
associated with the object. associated with the object.
7.6. Mapping of the REFERENCE clause 7.6. Mapping of the REFERENCE clause
The REFERENCE clause, which need not be present, contains a textual The REFERENCE clause, which need not be present, contains a textual
cross-reference to an object defined in some other information module. cross-reference to an object defined in some other information
This is useful when de-osifying a MIB module produced by some other module. This is useful when de-osifying a MIB module produced by
organization. some other organization.
7.7. Mapping of the INDEX clause 7.7. Mapping of the INDEX clause
The INDEX clause, which must be present if that object corresponds to a The INDEX clause, which must be present if that object corresponds to
conceptual row (unless an AUGMENTS clause is present instead), and must a conceptual row (unless an AUGMENTS clause is present instead), and
be absent otherwise, defines instance identification information for the must be absent otherwise, defines instance identification information
columnar objects subordinate to that object. for the columnar objects subordinate to that object.
The instance identification information in an INDEX clause must specify The instance identification information in an INDEX clause must
object(s) such that value(s) of those object(s) will unambiguously specify object(s) such that value(s) of those object(s) will
distinguish a conceptual row. The syntax of those objects indicate how unambiguously distinguish a conceptual row. The syntax of those
to form the instance-identifier: objects indicate how to form the instance-identifier:
(1) integer-valued: a single sub-identifier taking the integer value (1) integer-valued: a single sub-identifier taking the integer value
(this works only for non-negative integers); (this works only for non-negative integers);
(2) string-valued, fixed-length strings (or variable-length preceded by (2) string-valued, fixed-length strings (or variable-length preceded by
the IMPLIED keyword): `n' sub-identifiers, where `n' is the length the IMPLIED keyword): `n' sub-identifiers, where `n' is the length
of the string (each octet of the string is encoded in a separate of the string (each octet of the string is encoded in a separate
sub-identifier); sub-identifier);
(3) string-valued, variable-length strings (not preceded by the IMPLIED (3) string-valued, variable-length strings (not preceded by the IMPLIED
keyword): `n+1' sub-identifiers, where `n' is the length of the keyword): `n+1' sub-identifiers, where `n' is the length of the
string (the first sub-identifier is `n' itself, following this, string (the first sub-identifier is `n' itself, following this,
each octet of the string is encoded in a separate sub-identifier); each octet of the string is encoded in a separate sub-identifier);
(4) object identifier-valued (when preceded by the IMPLIED keyword): (4) object identifier-valued (when preceded by the IMPLIED keyword):
`n' sub-identifiers, where `n' is the number of sub-identifiers in `n' sub-identifiers, where `n' is the number of sub-identifiers in
the value (each sub-identifier of the value is copied into a the value (each sub-identifier of the value is copied into a
separate sub-identifier); separate sub-identifier);
(5) object identifier-valued (when not preceded by the IMPLIED (5) object identifier-valued (when not preceded by the IMPLIED
keyword): `n+1' sub-identifiers, where `n' is the number of sub- keyword): `n+1' sub-identifiers, where `n' is the number of sub-
identifiers in the value (the first sub-identifier is `n' itself, identifiers in the value (the first sub-identifier is `n' itself,
following this, each sub-identifier in the value is copied); following this, each sub-identifier in the value is copied);
(6) IpAddress-valued: 4 sub-identifiers, in the familiar a.b.c.d (6) IpAddress-valued: 4 sub-identifiers, in the familiar a.b.c.d
notation. notation.
Note that the IMPLIED keyword can only be present for an object having a Note that the IMPLIED keyword can only be present for an object
variable-length syntax (e.g., variable-length strings or object having a variable-length syntax (e.g., variable-length strings or
identifier-valued objects), Further, the IMPLIED keyword can only be object identifier-valued objects), Further, the IMPLIED keyword can
associated with the last object in the INDEX clause. Finally, the only be associated with the last object in the INDEX clause.
IMPLIED keyword may not be used on a variable-length string object if Finally, the IMPLIED keyword may not be used on a variable-length
that string might have a value of zero-length. string object if that string might have a value of zero-length.
Instances identified by use of integer-valued objects should be numbered Instances identified by use of integer-valued objects should be
starting from one (i.e., not from zero). The use of zero as a value for numbered starting from one (i.e., not from zero). The use of zero as
an integer-valued index object should be avoided, except in special a value for an integer-valued index object should be avoided, except
cases. in special cases.
Objects which are both specified in the INDEX clause of a conceptual row Objects which are both specified in the INDEX clause of a conceptual
and also columnar objects of the same conceptual row are termed row and also columnar objects of the same conceptual row are termed
auxiliary objects. The MAX-ACCESS clause for auxiliary objects is auxiliary objects. The MAX-ACCESS clause for auxiliary objects is
"not-accessible", except in the following circumstances: "not-accessible", except in the following circumstances:
(1) within a MIB module originally written to conform to the SNMPv1 (1) within a MIB module originally written to conform to the SNMPv1
framework, and later converted to conform to the SNMPv2 framework; framework, and later converted to conform to the SNMPv2 framework;
or or
(2) a conceptual row must contain at least one columnar object which is (2) a conceptual row must contain at least one columnar object which is
not an auxiliary object. In the event that all of a conceptual not an auxiliary object. In the event that all of a conceptual
row's columnar objects are also specified in its INDEX clause, then row's columnar objects are also specified in its INDEX clause, then
one of them must be accessible, i.e., have a MAX-ACCESS clause of one of them must be accessible, i.e., have a MAX-ACCESS clause of
"read-only". (Note that this situation does not arise for a "read-only". (Note that this situation does not arise for a
conceptual row allowing create access, since such a row will have a conceptual row allowing create access, since such a row will have a
status column which will not be an auxiliary object.) status column which will not be an auxiliary object.)
Note that objects specified in a conceptual row's INDEX clause need not Note that objects specified in a conceptual row's INDEX clause need
be columnar objects of that conceptual row. In this situation, the not be columnar objects of that conceptual row. In this situation,
DESCRIPTION clause of the conceptual row must include a textual the DESCRIPTION clause of the conceptual row must include a textual
explanation of how the objects which are included in the INDEX clause explanation of how the objects which are included in the INDEX clause
but not columnar objects of that conceptual row, are used in uniquely but not columnar objects of that conceptual row, are used in uniquely
identifying instances of the conceptual row's columnar objects. identifying instances of the conceptual row's columnar objects.
7.8. Mapping of the AUGMENTS clause 7.8. Mapping of the AUGMENTS clause
The AUGMENTS clause, which must not be present unless the object The AUGMENTS clause, which must not be present unless the object
corresponds to a conceptual row, is an alternative to the INDEX clause. corresponds to a conceptual row, is an alternative to the INDEX
Every object corresponding to a conceptual row has either an INDEX clause. Every object corresponding to a conceptual row has either an
clause or an AUGMENTS clause. INDEX clause or an AUGMENTS clause.
If an object corresponding to a conceptual row has an INDEX clause, that If an object corresponding to a conceptual row has an INDEX clause,
row is termed a base conceptual row; alternatively, if the object has an that row is termed a base conceptual row; alternatively, if the
AUGMENTS clause, the row is said to be a conceptual row augmentation, object has an AUGMENTS clause, the row is said to be a conceptual row
where the AUGMENTS clause names the object corresponding to the base augmentation, where the AUGMENTS clause names the object
conceptual row which is augmented by this conceptual row augmentation. corresponding to the base conceptual row which is augmented by this
(Thus, a conceptual row augmentation cannot itself be augmented.) conceptual row augmentation. (Thus, a conceptual row augmentation
Instances of subordinate columnar objects of a conceptual row cannot itself be augmented.) Instances of subordinate columnar
augmentation are identified according to the INDEX clause of the base objects of a conceptual row augmentation are identified according to
conceptual row corresponding to the object named in the AUGMENTS clause. the INDEX clause of the base conceptual row corresponding to the
Further, instances of subordinate columnar objects of a conceptual row object named in the AUGMENTS clause. Further, instances of
augmentation exist according to the same semantics as instances of subordinate columnar objects of a conceptual row augmentation exist
subordinate columnar objects of the base conceptual row being augmented. according to the same semantics as instances of subordinate columnar
As such, note that creation of a base conceptual row implies the objects of the base conceptual row being augmented. As such, note
correspondent creation of any conceptual row augmentations. that creation of a base conceptual row implies the correspondent
creation of any conceptual row augmentations.
For example, a MIB designer might wish to define additional columns in For example, a MIB designer might wish to define additional columns
an "enterprise-specific" MIB which logically extend a conceptual row in in an "enterprise-specific" MIB which logically extend a conceptual
a "standard" MIB. The "standard" MIB definition of the conceptual row row in a "standard" MIB. The "standard" MIB definition of the
would include the INDEX clause and the "enterprise-specific" MIB would conceptual row would include the INDEX clause and the "enterprise-
contain the definition of a conceptual row using the AUGMENTS clause. specific" MIB would contain the definition of a conceptual row using
On the other hand, it would be incorrect to use the AUGMENTS clause for the AUGMENTS clause. On the other hand, it would be incorrect to use
the relationship between RFC 1573's ifTable and the many media-specific the AUGMENTS clause for the relationship between RFC 1573's ifTable
MIBs which extend it for specific media (e.g., the dot3Table in RFC and the many media-specific MIBs which extend it for specific media
1650), since not all interfaces are of the same media. (e.g., the dot3Table in RFC 1650), since not all interfaces are of
the same media.
Note that a base conceptual row may be augmented by multiple conceptual Note that a base conceptual row may be augmented by multiple
row augmentations. conceptual row augmentations.
7.8.1. Relation between INDEX and AUGMENTS clauses 7.8.1. Relation between INDEX and AUGMENTS clauses
When defining instance identification information for a conceptual When defining instance identification information for a conceptual
table: table:
(1) If there is a one-to-one correspondence between the conceptual rows (1) If there is a one-to-one correspondence between the conceptual rows
of this table and an existing table, then the AUGMENTS clause of this table and an existing table, then the AUGMENTS clause
should be used. should be used.
(2) Otherwise, if there is a sparse relationship between the conceptual (2) Otherwise, if there is a sparse relationship between the conceptual
rows of this table and an existing table, then an INDEX clause rows of this table and an existing table, then an INDEX clause
should be used which is identical to that in the existing table. should be used which is identical to that in the existing table.
For example, the relationship between RFC 1573's ifTable and a For example, the relationship between RFC 1573's ifTable and a
media-specific MIB which extends the ifTable for a specific media media-specific MIB which extends the ifTable for a specific media
(e.g., the dot3Table in RFC 1650), is a sparse relationship. (e.g., the dot3Table in RFC 1650), is a sparse relationship.
(3) Otherwise, if no existing objects have the required syntax and (3) Otherwise, if no existing objects have the required syntax and
semantics, then auxiliary objects should be defined within the semantics, then auxiliary objects should be defined within the
conceptual row for the new table, and those objects should be used conceptual row for the new table, and those objects should be used
within the INDEX clause for the conceptual row. within the INDEX clause for the conceptual row.
7.9. Mapping of the DEFVAL clause 7.9. Mapping of the DEFVAL clause
The DEFVAL clause, which need not be present, defines an acceptable The DEFVAL clause, which need not be present, defines an acceptable
default value which may be used at the discretion of a SNMPv2 entity default value which may be used at the discretion of a SNMPv2 entity
acting in an agent role when an object instance is created. acting in an agent role when an object instance is created.
During conceptual row creation, if an instance of a columnar object is During conceptual row creation, if an instance of a columnar object
not present as one of the operands in the correspondent management is not present as one of the operands in the correspondent management
protocol set operation, then the value of the DEFVAL clause, if present, protocol set operation, then the value of the DEFVAL clause, if
indicates an acceptable default value that a SNMPv2 entity acting in an present, indicates an acceptable default value that a SNMPv2 entity
agent role might use. acting in an agent role might use.
The value of the DEFVAL clause must, of course, correspond to the SYNTAX The value of the DEFVAL clause must, of course, correspond to the
clause for the object. If the value is an OBJECT IDENTIFIER, then it SYNTAX clause for the object. If the value is an OBJECT IDENTIFIER,
must be expressed as a single ASN.1 identifier, and not as a collection then it must be expressed as a single ASN.1 identifier, and not as a
of sub-identifiers. collection of sub-identifiers.
Note that if an operand to the management protocol set operation is an Note that if an operand to the management protocol set operation is
instance of a read-only object, then the error `notWritable' [6] will be an instance of a read-only object, then the error `notWritable' [6]
returned. As such, the DEFVAL clause can be used to provide an will be returned. As such, the DEFVAL clause can be used to provide
acceptable default value that a SNMPv2 entity acting in an agent role an acceptable default value that a SNMPv2 entity acting in an agent
might use. role might use.
By way of example, consider the following possible DEFVAL clauses: By way of example, consider the following possible DEFVAL clauses:
ObjectSyntax DEFVAL clause ObjectSyntax DEFVAL clause
---------------- ------------ ---------------- ------------
Integer32 DEFVAL { 1 } Integer32 DEFVAL { 1 }
-- same for Gauge32, TimeTicks, Unsigned32 -- same for Gauge32, TimeTicks, Unsigned32
INTEGER DEFVAL { valid } -- enumerated value INTEGER DEFVAL { valid } -- enumerated value
OCTET STRING DEFVAL { 'ffffffffffff'H } OCTET STRING DEFVAL { 'ffffffffffff'H }
OBJECT IDENTIFIER DEFVAL { sysDescr } OBJECT IDENTIFIER DEFVAL { sysDescr }
BITS DEFVAL { { primary, secondary } } BITS DEFVAL { { primary, secondary } }
-- enumerated values that are set -- enumerated values that are set
IpAddress DEFVAL { 'c0210415'H } -- 192.33.4.21 IpAddress DEFVAL { 'c0210415'H } -- 192.33.4.21
Object types with SYNTAX of Counter32 and Counter64 may not have DEFVAL Object types with SYNTAX of Counter32 and Counter64 may not have
clauses, since they do not have defined initial values. However, it is DEFVAL clauses, since they do not have defined initial values.
recommended that they be initialized to zero. However, it is recommended that they be initialized to zero.
7.10. Mapping of the OBJECT-TYPE value 7.10. Mapping of the OBJECT-TYPE value
The value of an invocation of the OBJECT-TYPE macro is the name of the The value of an invocation of the OBJECT-TYPE macro is the name of
object, which is an OBJECT IDENTIFIER, an administratively assigned the object, which is an OBJECT IDENTIFIER, an administratively
name. assigned name.
When an OBJECT IDENTIFIER is assigned to an object: When an OBJECT IDENTIFIER is assigned to an object:
(1) If the object corresponds to a conceptual table, then only a single (1) If the object corresponds to a conceptual table, then only a single
assignment, that for a conceptual row, is present immediately assignment, that for a conceptual row, is present immediately
beneath that object. The administratively assigned name for the beneath that object. The administratively assigned name for the
conceptual row object is derived by appending a sub-identifier of conceptual row object is derived by appending a sub-identifier of
"1" to the administratively assigned name for the conceptual table. "1" to the administratively assigned name for the conceptual table.
(2) If the object corresponds to a conceptual row, then at least one (2) If the object corresponds to a conceptual row, then at least one
assignment, one for each column in the conceptual row, is present assignment, one for each column in the conceptual row, is present
beneath that object. The administratively assigned name for each beneath that object. The administratively assigned name for each
column is derived by appending a unique, positive sub-identifier to column is derived by appending a unique, positive sub-identifier to
the administratively assigned name for the conceptual row. the administratively assigned name for the conceptual row.
(3) Otherwise, no other OBJECT IDENTIFIERs which are subordinate to the (3) Otherwise, no other OBJECT IDENTIFIERs which are subordinate to the
object may be assigned. object may be assigned.
Note that the final sub-identifier of any administratively assigned name Note that the final sub-identifier of any administratively assigned
for an object shall be positive. A zero-valued final sub-identifier is name for an object shall be positive. A zero-valued final sub-
reserved for future use. identifier is reserved for future use.
Further note that although conceptual tables and rows are given Further note that although conceptual tables and rows are given
administratively assigned names, these conceptual objects may not be administratively assigned names, these conceptual objects may not be
manipulated in aggregate form by the management protocol. manipulated in aggregate form by the management protocol.
7.11. Usage Example 7.11. Usage Example
Consider how one might define a conceptual table and its subordinates. Consider how one might define a conceptual table and its
(This example uses the RowStatus textual convention defined in [3].) subordinates. (This example uses the RowStatus textual convention
defined in [3].)
evalSlot OBJECT-TYPE evalSlot OBJECT-TYPE
SYNTAX INTEGER SYNTAX INTEGER
MAX-ACCESS read-only MAX-ACCESS read-only
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"The index number of the first unassigned entry in the "The index number of the first unassigned entry in the
evaluation table. evaluation table.
A management station should create new entries in the A management station should create new entries in the
evaluation table using this algorithm: first, issue a evaluation table using this algorithm: first, issue a
management protocol retrieval operation to determine the management protocol retrieval operation to determine the
value of evalSlot; and, second, issue a management protocol value of evalSlot; and, second, issue a management protocol
set operation to create an instance of the evalStatus object set operation to create an instance of the evalStatus object
setting its value to createAndGo(4) or createAndWait(5). If setting its value to createAndGo(4) or createAndWait(5). If
this latter operation succeeds, then the management station this latter operation succeeds, then the management station
may continue modifying the instances corresponding to the may continue modifying the instances corresponding to the
newly created conceptual row, without fear of collision with newly created conceptual row, without fear of collision with
other management stations." other management stations."
::= { eval 1 } ::= { eval 1 }
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STATUS current STATUS current
DESCRIPTION DESCRIPTION
"The status column used for creating, modifying, and "The status column used for creating, modifying, and
deleting instances of the columnar objects in the evaluation deleting instances of the columnar objects in the evaluation
table." table."
DEFVAL { active } DEFVAL { active }
::= { evalEntry 4 } ::= { evalEntry 4 }
8. Mapping of the NOTIFICATION-TYPE macro 8. Mapping of the NOTIFICATION-TYPE macro
The NOTIFICATION-TYPE macro is used to define the information contained The NOTIFICATION-TYPE macro is used to define the information
within an unsolicited transmission of management information (i.e., contained within an unsolicited transmission of management
within either a SNMPv2-Trap-PDU or InformRequest-PDU). It should be information (i.e., within either a SNMPv2-Trap-PDU or InformRequest-
noted that the expansion of the NOTIFICATION-TYPE macro is something PDU). It should be noted that the expansion of the NOTIFICATION-TYPE
which conceptually happens during implementation and not during run- macro is something which conceptually happens during implementation
time. and not during run-time.
8.1. Mapping of the OBJECTS clause 8.1. Mapping of the OBJECTS clause
The OBJECTS clause, which need not be present, defines the ordered The OBJECTS clause, which need not be present, defines the ordered
sequence of MIB object types which are contained within every instance sequence of MIB object types which are contained within every
of the notification. An object type specified in this clause may not instance of the notification. An object type specified in this
have an MAX-ACCESS clause of "not-accessible". clause may not have an MAX-ACCESS clause of "not-accessible".
8.2. Mapping of the STATUS clause 8.2. Mapping of the STATUS clause
The STATUS clause, which must be present, indicates whether this The STATUS clause, which must be present, indicates whether this
definition is current or historic. definition is current or historic.
The values "current", and "obsolete" are self-explanatory. The The values "current", and "obsolete" are self-explanatory. The
"deprecated" value indicates that the definition is obsolete, but that "deprecated" value indicates that the definition is obsolete, but
an implementor may wish to support the notification to foster that an implementor may wish to support the notification to foster
interoperability with older implementations. interoperability with older implementations.
8.3. Mapping of the DESCRIPTION clause 8.3. Mapping of the DESCRIPTION clause
The DESCRIPTION clause, which must be present, contains a textual The DESCRIPTION clause, which must be present, contains a textual
definition of the notification which provides all semantic definitions definition of the notification which provides all semantic
necessary for implementation, and should embody any information which definitions necessary for implementation, and should embody any
would otherwise be communicated in any ASN.1 commentary annotations information which would otherwise be communicated in any ASN.1
associated with the notification. In particular, the DESCRIPTION clause commentary annotations associated with the notification. In
should document which instances of the objects mentioned in the OBJECTS particular, the DESCRIPTION clause should document which instances of
clause should be contained within notifications of this type. the objects mentioned in the OBJECTS clause should be contained
within notifications of this type.
8.4. Mapping of the REFERENCE clause 8.4. Mapping of the REFERENCE clause
The REFERENCE clause, which need not be present, contains a textual The REFERENCE clause, which need not be present, contains a textual
cross-reference to a notification defined in some other information cross-reference to a notification defined in some other information
module. This is useful when de-osifying a MIB module produced by some module. This is useful when de-osifying a MIB module produced by
other organization. some other organization.
8.5. Mapping of the NOTIFICATION-TYPE value 8.5. Mapping of the NOTIFICATION-TYPE value
The value of an invocation of the NOTIFICATION-TYPE macro is the name of The value of an invocation of the NOTIFICATION-TYPE macro is the name
the notification, which is an OBJECT IDENTIFIER, an administratively of the notification, which is an OBJECT IDENTIFIER, an
assigned name. In order to achieve compatibility with the procedures administratively assigned name. In order to achieve compatibility
employed by proxy agents (see Section 3.1.2 of [7]), the next to last with the procedures employed by proxy agents (see Section 3.1.2 of
sub-identifier in the name of any newly-defined notification must have [7]), the next to last sub-identifier in the name of any newly-
the value zero. defined notification must have the value zero.
Sections 4.2.6 and 4.2.7 of [6] describe how the NOTIFICATION-TYPE macro Sections 4.2.6 and 4.2.7 of [6] describe how the NOTIFICATION-TYPE
is used to generate a SNMPv2-Trap-PDU or InformRequest-PDU, macro is used to generate a SNMPv2-Trap-PDU or InformRequest-PDU,
respectively. respectively.
8.6. Usage Example 8.6. Usage Example
Consider how a linkUp trap might be described: Consider how a linkUp trap might be described:
linkUp NOTIFICATION-TYPE linkUp NOTIFICATION-TYPE
OBJECTS { ifIndex } OBJECTS { ifIndex }
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"A linkUp trap signifies that the SNMPv2 entity, acting in "A linkUp trap signifies that the SNMPv2 entity, acting in
an agent role, recognizes that one of the communication an agent role, recognizes that one of the communication
links represented in its configuration has come up." links represented in its configuration has come up."
::= { snmpTraps 4 } ::= { snmpTraps 4 }
According to this invocation, the trap authoritatively identified as According to this invocation, the trap authoritatively identified as
{ snmpTraps 4 } { snmpTraps 4 }
is used to report a link coming up. is used to report a link coming up.
9. Refined Syntax 9. Refined Syntax
Some macros have clauses which allows syntax to be refined, Some macros have clauses which allows syntax to be refined,
specifically: the SYNTAX clause of the OBJECT-TYPE macro, and the specifically: the SYNTAX clause of the OBJECT-TYPE macro, and the
SYNTAX/WRITE-SYNTAX clauses of the MODULE-COMPLIANCE and AGENT- SYNTAX/WRITE-SYNTAX clauses of the MODULE-COMPLIANCE and AGENT-
CAPABILITIES macros [2]. However, not all refinements of syntax are CAPABILITIES macros [2]. However, not all refinements of syntax are
appropriate. In particular, the object's primitive or application type appropriate. In particular, the object's primitive or application
must not be changed. type must not be changed.
Further, the following restrictions apply: Further, the following restrictions apply:
Restrictions to Refinement on Restrictions to Refinement on
object syntax range enumeration size repertoire object syntax range enumeration size repertoire
----------------- ----- ----------- ---- ---------- ----------------- ----- ----------- ---- ----------
INTEGER (1) (2) - - INTEGER (1) (2) - -
Integer32 (1) - - - Integer32 (1) - - -
Unsigned32 (1) - - - Unsigned32 (1) - - -
OCTET STRING - - (3) (4) OCTET STRING - - (3) (4)
OBJECT IDENTIFIER - - - - OBJECT IDENTIFIER - - - -
BITS - (2) - - BITS - (2) - -
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more named-values (note that for BITS, a refinement may cause the more named-values (note that for BITS, a refinement may cause the
enumerations to no longer be contiguous); enumerations to no longer be contiguous);
(3) the size in characters of the value may be refined by raising the (3) the size in characters of the value may be refined by raising the
lower-bounds, by reducing the upper-bounds, and/or by reducing the lower-bounds, by reducing the upper-bounds, and/or by reducing the
alternative size choices; or, alternative size choices; or,
(4) the repertoire of characters in the value may be reduced by further (4) the repertoire of characters in the value may be reduced by further
sub-typing. sub-typing.
Otherwise no refinements are possible. Further details on sub-typing Otherwise no refinements are possible. Further details on sub-typing
are provided in Appendix C. are provided in Appendix C.
10. Extending an Information Module 10. Extending an Information Module
As experience is gained with a published information module, it may be As experience is gained with a published information module, it may
desirable to revise that information module. be desirable to revise that information module.
To begin, the invocation of the MODULE-IDENTITY macro should be updated To begin, the invocation of the MODULE-IDENTITY macro should be
to include information about the revision. Usually, this consists of updated to include information about the revision. Usually, this
updating the LAST-UPDATED clause and adding a pair of REVISION and consists of updating the LAST-UPDATED clause and adding a pair of
DESCRIPTION clauses. However, other existing clauses in the invocation REVISION and DESCRIPTION clauses. However, other existing clauses in
may be updated. the invocation may be updated.
Note that the module's label (e.g., "FIZBIN-MIB" from the example in Note that the module's label (e.g., "FIZBIN-MIB" from the example in
Section 5.8), is not changed when the information module is revised. Section 5.8), is not changed when the information module is revised.
10.1. Object Assignments 10.1. Object Assignments
If any non-editorial change is made to any clause of a object If any non-editorial change is made to any clause of a object
assignment, then the OBJECT IDENTIFIER value associated with that object assignment, then the OBJECT IDENTIFIER value associated with that
assignment must also be changed, along with its associated descriptor. object assignment must also be changed, along with its associated
descriptor.
10.2. Object Definitions 10.2. Object Definitions
An object definition may be revised in any of the following ways: An object definition may be revised in any of the following ways:
(1) A SYNTAX clause containing an enumerated INTEGER may have new (1) A SYNTAX clause containing an enumerated INTEGER may have new
enumerations added or existing labels changed. enumerations added or existing labels changed.
(2) A STATUS clause value of "current" may be revised as "deprecated" (2) A STATUS clause value of "current" may be revised as "deprecated"
or "obsolete". Similarly, a STATUS clause value of "deprecated" or "obsolete". Similarly, a STATUS clause value of "deprecated"
may be revised as "obsolete". may be revised as "obsolete".
(3) A DEFVAL clause may be added or updated. (3) A DEFVAL clause may be added or updated.
(4) A REFERENCE clause may be added or updated. (4) A REFERENCE clause may be added or updated.
(5) A UNITS clause may be added. (5) A UNITS clause may be added.
(6) A conceptual row may be augmented by adding new columnar objects at (6) A conceptual row may be augmented by adding new columnar objects at
the end of the row. the end of the row.
(7) Entirely new objects may be defined, named with previously (7) Entirely new objects may be defined, named with previously
unassigned OBJECT IDENTIFIER values. unassigned OBJECT IDENTIFIER values.
Otherwise, if the semantics of any previously defined object are changed Otherwise, if the semantics of any previously defined object are
(i.e., if a non-editorial change is made to any clause other those changed (i.e., if a non-editorial change is made to any clause other
specifically allowed above), then the OBJECT IDENTIFIER value associated those specifically allowed above), then the OBJECT IDENTIFIER value
with that object must also be changed. associated with that object must also be changed.
Note that changing the descriptor associated with an existing object is Note that changing the descriptor associated with an existing object
considered a semantic change, as these strings may be used in an IMPORTS is considered a semantic change, as these strings may be used in an
statement. IMPORTS statement.
Finally, note that if an object has the value of its STATUS clause Finally, note that if an object has the value of its STATUS clause
changed, then the value of its DESCRIPTION clause should be updated changed, then the value of its DESCRIPTION clause should be updated
accordingly. accordingly.
10.3. Notification Definitions 10.3. Notification Definitions
A notification definition may be revised in any of the following ways: A notification definition may be revised in any of the following
ways:
(1) A REFERENCE clause may be added or updated. (1) A REFERENCE clause may be added or updated.
Otherwise, if the semantics of any previously defined notification are Otherwise, if the semantics of any previously defined notification
changed (i.e., if a non-editorial change is made to any clause other are changed (i.e., if a non-editorial change is made to any clause
those specifically allowed above), then the OBJECT IDENTIFIER value other those specifically allowed above), then the OBJECT IDENTIFIER
associated with that notification must also be changed. value associated with that notification must also be changed.
Note that changing the descriptor associated with an existing Note that changing the descriptor associated with an existing
notification is considered a semantic change, as these strings may be notification is considered a semantic change, as these strings may be
used in an IMPORTS statement. used in an IMPORTS statement.
Finally, note that if an object has the value of its STATUS clause Finally, note that if an object has the value of its STATUS clause
changed, then the value of its DESCRIPTION clause should be updated changed, then the value of its DESCRIPTION clause should be updated
accordingly. accordingly.
11. Appendix A: de-OSIfying a MIB module 11. Appendix A: de-OSIfying a MIB module
There has been an increasing amount of work recently on taking MIBs There has been an increasing amount of work recently on taking MIBs
defined by other organizations (e.g., the IEEE) and de-osifying them for defined by other organizations (e.g., the IEEE) and de-osifying them
use with the Internet-standard network management framework. The steps for use with the Internet-standard network management framework. The
to achieve this are straight-forward, though tedious. Of course, it is steps to achieve this are straight-forward, though tedious. Of
helpful to already be experienced in writing MIB modules for use with course, it is helpful to already be experienced in writing MIB
the Internet-standard network management framework. modules for use with the Internet-standard network management
framework.
The first step is to construct a skeletal MIB module, as shown earlier The first step is to construct a skeletal MIB module, as shown
in Section 5.8. The next step is to categorize the objects into groups. earlier in Section 5.8. The next step is to categorize the objects
Optional objects are not permitted. Thus, when a MIB module is created, into groups. Optional objects are not permitted. Thus, when a MIB
optional objects must be placed in a additional groups, which, if module is created, optional objects must be placed in a additional
implemented, all objects in the group must be implemented. For the groups, which, if implemented, all objects in the group must be
first pass, it is wisest to simply ignore any optional objects in the implemented. For the first pass, it is wisest to simply ignore any
original MIB: experience shows it is better to define a core MIB module optional objects in the original MIB: experience shows it is better
first, containing only essential objects; later, if experience demands, to define a core MIB module first, containing only essential objects;
other objects can be added. later, if experience demands, other objects can be added.
11.1. Managed Object Mapping 11.1. Managed Object Mapping
Next for each managed object class, determine whether there can exist Next for each managed object class, determine whether there can exist
multiple instances of that managed object class. If not, then for each multiple instances of that managed object class. If not, then for
of its attributes, use the OBJECT-TYPE macro to make an equivalent each of its attributes, use the OBJECT-TYPE macro to make an
definition. equivalent definition.
Otherwise, if multiple instances of the managed object class can exist, Otherwise, if multiple instances of the managed object class can
then define a conceptual table having conceptual rows each containing a exist, then define a conceptual table having conceptual rows each
columnar object for each of the managed object class's attributes. If containing a columnar object for each of the managed object class's
the managed object class is contained within the containment tree of attributes. If the managed object class is contained within the
another managed object class, then the assignment of an object is containment tree of another managed object class, then the assignment
normally required for each of the "distinguished attributes" of the of an object is normally required for each of the "distinguished
containing managed object class. If they do not already exist within attributes" of the containing managed object class. If they do not
the MIB module, then they can be added via the definition of additional already exist within the MIB module, then they can be added via the
columnar objects in the conceptual row corresponding to the contained definition of additional columnar objects in the conceptual row
managed object class. corresponding to the contained managed object class.
In defining a conceptual row, it is useful to consider the optimization In defining a conceptual row, it is useful to consider the
of network management operations which will act upon its columnar optimization of network management operations which will act upon its
objects. In particular, it is wisest to avoid defining more columnar columnar objects. In particular, it is wisest to avoid defining more
objects within a conceptual row, than can fit in a single PDU. As a columnar objects within a conceptual row, than can fit in a single
rule of thumb, a conceptual row should contain no more than PDU. As a rule of thumb, a conceptual row should contain no more
approximately 20 objects. Similarly, or as a way to abide by the "20 than approximately 20 objects. Similarly, or as a way to abide by
object guideline", columnar objects should be grouped into tables the "20 object guideline", columnar objects should be grouped into
according to the expected grouping of network management operations upon tables according to the expected grouping of network management
them. As such, the content of conceptual rows should reflect typical operations upon them. As such, the content of conceptual rows should
access scenarios, e.g., they should be organized along functional lines reflect typical access scenarios, e.g., they should be organized
such as one row for statistics and another row for parameters, or along along functional lines such as one row for statistics and another row
usage lines such as commonly-needed objects versus rarely-needed for parameters, or along usage lines such as commonly-needed objects
objects. versus rarely-needed objects.
On the other hand, the definition of conceptual rows where the number of On the other hand, the definition of conceptual rows where the number
columnar objects used as indexes outnumbers the number used to hold of columnar objects used as indexes outnumbers the number used to
information, should also be avoided. In particular, the splitting of a hold information, should also be avoided. In particular, the
managed object class's attributes into many conceptual tables should not splitting of a managed object class's attributes into many conceptual
be used as a way to obtain the same degree of flexibility/complexity as tables should not be used as a way to obtain the same degree of
is often found in MIBs with a myriad of optionals. flexibility/complexity as is often found in MIBs with a myriad of
optionals.
11.1.1. Mapping to the SYNTAX clause 11.1.1. Mapping to the SYNTAX clause
When mapping to the SYNTAX clause of the OBJECT-TYPE macro: When mapping to the SYNTAX clause of the OBJECT-TYPE macro:
(1) An object with BOOLEAN syntax becomes a TruthValue [3]. (1) An object with BOOLEAN syntax becomes a TruthValue [3].
(2) An object with INTEGER syntax becomes an Integer32. (2) An object with INTEGER syntax becomes an Integer32.
(3) An object with ENUMERATED syntax becomes an INTEGER with (3) An object with ENUMERATED syntax becomes an INTEGER with
enumerations, taking any of the values given which can be enumerations, taking any of the values given which can be
represented with an Integer32. represented with an Integer32.
(4) An object with BIT STRING syntax having enumerations becomes a BITS (4) An object with BIT STRING syntax having enumerations becomes a BITS
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(7) A non-tabular object with a complex syntax, such as REAL or (7) A non-tabular object with a complex syntax, such as REAL or
EXTERNAL, must be decomposed, usually into an OCTET STRING (if EXTERNAL, must be decomposed, usually into an OCTET STRING (if
sensible). As a rule, any object with a complicated syntax should sensible). As a rule, any object with a complicated syntax should
be avoided. be avoided.
(8) Tabular objects must be decomposed into rows of columnar objects. (8) Tabular objects must be decomposed into rows of columnar objects.
11.1.2. Mapping to the UNITS clause 11.1.2. Mapping to the UNITS clause
If the description of this managed object defines a unit-basis, then If the description of this managed object defines a unit-basis, then
mapping to this clause is straight-forward. mapping to this clause is straight-forward.
11.1.3. Mapping to the MAX-ACCESS clause 11.1.3. Mapping to the MAX-ACCESS clause
This is straight-forward. This is straight-forward.
11.1.4. Mapping to the STATUS clause 11.1.4. Mapping to the STATUS clause
This is straight-forward. This is straight-forward.
11.1.5. Mapping to the DESCRIPTION clause 11.1.5. Mapping to the DESCRIPTION clause
This is straight-forward: simply copy the text, making sure that any This is straight-forward: simply copy the text, making sure that any
embedded double quotation marks are sanitized (i.e., replaced with embedded double quotation marks are sanitized (i.e., replaced with
single-quotes or removed). single-quotes or removed).
11.1.6. Mapping to the REFERENCE clause 11.1.6. Mapping to the REFERENCE clause
This is straight-forward: simply include a textual reference to the This is straight-forward: simply include a textual reference to the
object being mapped, the document which defines the object, and perhaps object being mapped, the document which defines the object, and
a page number in the document. perhaps a page number in the document.
11.1.7. Mapping to the INDEX clause 11.1.7. Mapping to the INDEX clause
If necessary, decide how instance-identifiers for columnar objects are If necessary, decide how instance-identifiers for columnar objects
to be formed and define this clause accordingly. are to be formed and define this clause accordingly.
11.1.8. Mapping to the DEFVAL clause 11.1.8. Mapping to the DEFVAL clause
Decide if a meaningful default value can be assigned to the object being Decide if a meaningful default value can be assigned to the object
mapped, and if so, define the DEFVAL clause accordingly. being mapped, and if so, define the DEFVAL clause accordingly.
11.2. Action Mapping 11.2. Action Mapping
Actions are modeled as read-write objects, in which writing a particular Actions are modeled as read-write objects, in which writing a
value results in a state change. (Usually, as a part of this state particular value results in a state change. (Usually, as a part of
change, some action might take place.) this state change, some action might take place.)
11.2.1. Mapping to the SYNTAX clause 11.2.1. Mapping to the SYNTAX clause
Usually the Integer32 syntax is used with a distinguished value provided Usually the Integer32 syntax is used with a distinguished value
for each action that the object provides access to. In addition, there provided for each action that the object provides access to. In
is usually one other distinguished value, which is the one returned when addition, there is usually one other distinguished value, which is
the object is read. the one returned when the object is read.
11.2.2. Mapping to the MAX-ACCESS clause 11.2.2. Mapping to the MAX-ACCESS clause
Always use read-write or read-create. Always use read-write or read-create.
11.2.3. Mapping to the STATUS clause 11.2.3. Mapping to the STATUS clause
This is straight-forward. This is straight-forward.
11.2.4. Mapping to the DESCRIPTION clause 11.2.4. Mapping to the DESCRIPTION clause
This is straight-forward: simply copy the text, making sure that any This is straight-forward: simply copy the text, making sure that any
embedded double quotation marks are sanitized (i.e., replaced with embedded double quotation marks are sanitized (i.e., replaced with
single-quotes or removed). single-quotes or removed).
11.2.5. Mapping to the REFERENCE clause 11.2.5. Mapping to the REFERENCE clause
This is straight-forward: simply include a textual reference to the This is straight-forward: simply include a textual reference to the
action being mapped, the document which defines the action, and perhaps action being mapped, the document which defines the action, and
a page number in the document. perhaps a page number in the document.
11.3. Event Mapping 11.3. Event Mapping
Events are modeled as SNMPv2 notifications using NOTIFICATION-TYPE Events are modeled as SNMPv2 notifications using NOTIFICATION-TYPE
macro. However, recall that SNMPv2 emphasizes trap-directed polling. macro. However, recall that SNMPv2 emphasizes trap-directed polling.
As such, few, and usually no, notifications, need be defined for any MIB As such, few, and usually no, notifications, need be defined for any
module. MIB module.
11.3.1. Mapping to the STATUS clause 11.3.1. Mapping to the STATUS clause
This is straight-forward. This is straight-forward.
11.3.2. Mapping to the DESCRIPTION clause 11.3.2. Mapping to the DESCRIPTION clause
This is straight-forward: simply copy the text, making sure that any This is straight-forward: simply copy the text, making sure that any
embedded double quotation marks are sanitized (i.e., replaced with embedded double quotation marks are sanitized (i.e., replaced with
single-quotes or removed). single-quotes or removed).
11.3.3. Mapping to the REFERENCE clause 11.3.3. Mapping to the REFERENCE clause
This is straight-forward: simply include a textual reference to the This is straight-forward: simply include a textual reference to the
notification being mapped, the document which defines the notification, notification being mapped, the document which defines the
and perhaps a page number in the document. notification, and perhaps a page number in the document.
12. Appendix B: UTC Time Format 12. Appendix B: UTC Time Format
Several clauses defined in this document use the UTC Time format: Several clauses defined in this document use the UTC Time format:
YYMMDDHHMMZ YYMMDDHHMMZ
where: YY - last two digits of year where: YY - last two digits of year
MM - month (01 through 12) MM - month (01 through 12)
DD - day of month (01 through 31) DD - day of month (01 through 31)
HH - hours (00 through 23) HH - hours (00 through 23)
MM - minutes (00 through 59) MM - minutes (00 through 59)
Z - the character "Z" denotes Greenwich Mean Time (GMT). Z - the character "Z" denotes Greenwich Mean Time (GMT).
For example, "9502192015Z" represents 8:15pm GMT on 19 February 1995. For example, "9502192015Z" represents 8:15pm GMT on 19 February 1995.
13. Appendix C: Detailed Sub-typing Rules 13. Appendix C: Detailed Sub-typing Rules
13.1. Syntax Rules 13.1. Syntax Rules
The syntax rules for sub-typing are given below. Note that while this The syntax rules for sub-typing are given below. Note that while
syntax is based on ASN.1, it includes some extensions beyond what is this syntax is based on ASN.1, it includes some extensions beyond
allowed in ASN.1, and a number of ASN.1 constructs are not allowed by what is allowed in ASN.1, and a number of ASN.1 constructs are not
this syntax. allowed by this syntax.
<integerSubType> <integerSubType>
::= <empty> ::= <empty>
| "(" <range> ["|" <range>]... ")" | "(" <range> ["|" <range>]... ")"
<octetStringSubType> <octetStringSubType>
::= <empty> ::= <empty>
| "(" "SIZE" "(" <range> ["|" <range>]... ")" ")" | "(" "SIZE" "(" <range> ["|" <range>]... ")" ")"
<range> <range>
skipping to change at page 50, line 29 skipping to change at page 38, line 38
Integer32 (150..100) -- first greater than second Integer32 (150..100) -- first greater than second
Integer32 (0..100 | 50..500) -- ranges overlap Integer32 (0..100 | 50..500) -- ranges overlap
Integer32 (0 | 2 | 0 ) -- value duplicated Integer32 (0 | 2 | 0 ) -- value duplicated
Integer32 (MIN..-1 | 1..MAX) -- MIN and MAX not allowed Integer32 (MIN..-1 | 1..MAX) -- MIN and MAX not allowed
Integer32 ((SIZE (0..34)) -- must not use SIZE Integer32 ((SIZE (0..34)) -- must not use SIZE
OCTET STRING (0..100) -- must use SIZE OCTET STRING (0..100) -- must use SIZE
OCTET STRING (SIZE(-10..100)) -- negative SIZE OCTET STRING (SIZE(-10..100)) -- negative SIZE
13.3. Rules for Textual Conventions 13.3. Rules for Textual Conventions
Sub-typing of Textual Conventions (see [3]) is allowed but must be Sub-typing of Textual Conventions (see [3]) is allowed but must be
valid. In particular, each range specified for the textual convention valid. In particular, each range specified for the textual
must be a subset of a range specified for the base type. For example, convention must be a subset of a range specified for the base type.
For example,
Tc1 ::= INTEGER (1..10 | 11..20) Tc1 ::= INTEGER (1..10 | 11..20)
Tc2 ::= Tc1 (2..10 | 12..15) -- is valid Tc2 ::= Tc1 (2..10 | 12..15) -- is valid
Tc3 ::= Tc1 (4..8) -- is valid Tc3 ::= Tc1 (4..8) -- is valid
Tc4 ::= Tc1 (8..12) -- is invalid Tc4 ::= Tc1 (8..12) -- is invalid
14. Acknowledgements 14. Security Considerations
This document is the result of significant work by the four major Security issues are not discussed in this memo.
contributors:
Jeffrey Case (SNMP Research, case@snmp.com) 15. Editor's Address
Keith McCloghrie (Cisco Systems, kzm@cisco.com)
Marshall Rose (Dover Beach Consulting, mrose@dbc.mtview.ca.us)
Steven Waldbusser (International Network Services, stevew@uni.ins.com)
In addition, the contributions of the SNMPv2 Working Group are Keith McCloghrie
acknowledged. In particular, a special thanks is extended for the Cisco Systems, Inc.
contributions of: 170 West Tasman Drive
San Jose, CA 95134-1706
US
Phone: +1 408 526 5260
EMail: kzm@cisco.com
16. Acknowledgements
This document is the result of significant work by the four major
contributors:
Jeffrey D. Case (SNMP Research, case@snmp.com)
Keith McCloghrie (Cisco Systems, kzm@cisco.com)
Marshall T. Rose (Dover Beach Consulting, mrose@dbc.mtview.ca.us)
Steven Waldbusser (International Network Services, stevew@uni.ins.com)
In addition, the contributions of the SNMPv2 Working Group are
acknowledged. In particular, a special thanks is extended for the
contributions of:
Alexander I. Alten (Novell) Alexander I. Alten (Novell)
Dave Arneson (Cabletron) Dave Arneson (Cabletron)
Uri Blumenthal (IBM) Uri Blumenthal (IBM)
Doug Book (Chipcom) Doug Book (Chipcom)
Kim Curran (Bell-Northern Research) Kim Curran (Bell-Northern Research)
Jim Galvin (Trusted Information Systems) Jim Galvin (Trusted Information Systems)
Maria Greene (Ascom Timeplex) Maria Greene (Ascom Timeplex)
Iain Hanson (Digital) Iain Hanson (Digital)
Dave Harrington (Cabletron) Dave Harrington (Cabletron)
skipping to change at page 52, line 5 skipping to change at page 40, line 9
Dave Perkins (Peer Networks) Dave Perkins (Peer Networks)
Randy Presuhn (Peer Networks) Randy Presuhn (Peer Networks)
Aleksey Romanov (Quality Quorum) Aleksey Romanov (Quality Quorum)
Shawn Routhier (Epilogue) Shawn Routhier (Epilogue)
Jon Saperia (BGS Systems) Jon Saperia (BGS Systems)
Bob Stewart (Cisco Systems, bstewart@cisco.com), chair Bob Stewart (Cisco Systems, bstewart@cisco.com), chair
Kaj Tesink (Bellcore) Kaj Tesink (Bellcore)
Glenn Waters (Bell-Northern Research) Glenn Waters (Bell-Northern Research)
Bert Wijnen (IBM) Bert Wijnen (IBM)
15. References 17. References
[1] Information processing systems - Open Systems Interconnection - [1] Information processing systems - Open Systems Interconnection -
Specification of Abstract Syntax Notation One (ASN.1), Specification of Abstract Syntax Notation One (ASN.1),
International Organization for Standardization. International International Organization for Standardization. International
Standard 8824, (December, 1987). Standard 8824, (December, 1987).
[2] McCloghrie, K., Editor, | [2] SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M., and
"Conformance Statements for Version 2 of the Simple Network S. Waldbusser, "Conformance Statements for Version 2 of the Simple
Management Protocol (SNMPv2)", Internet Draft, Cisco Systems, | Network Management Protocol (SNMPv2)", RFC 1904, January 1996.
September 1995. |
[3] McCloghrie, K., Editor, | [3] SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M., and
"Textual Conventions for Version 2 of the Simple Network Management S. Waldbusser, "Textual Conventions for Version 2 of the Simple
Protocol (SNMPv2)", Internet Draft, Cisco Systems, September 1995. | Network Management Protocol (SNMPv2)", RFC 1903, January 1996.
[4] Information processing systems - Open Systems Interconnection - [4] Information processing systems - Open Systems Interconnection -
Specification of Basic Encoding Rules for Abstract Syntax Notation Specification of Basic Encoding Rules for Abstract Syntax Notation
One (ASN.1), International Organization for Standardization. One (ASN.1), International Organization for Standardization.
International Standard 8825, (December, 1987). International Standard 8825, (December, 1987).
[5] McCloghrie, K., Editor, | [5] SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M., and
"Management Information Base for Version 2 of the Simple Network S. Waldbusser, "Management Information Base for Version 2 of the
Management Protocol (SNMPv2)", Internet Draft, Cisco Systems, | Simple Network Management Protocol (SNMPv2)", RFC 1907,
September 1995. | January 1996.
[6] McCloghrie, K., Editor, |
"Protocol Operations for Version 2 of the Simple Network Management
Protocol (SNMPv2)", Internet Draft, Cisco Systems, September 1995. |
[7] McCloghrie, K., Editor, |
"Coexistence between Version 1 and Version 2 of the Internet-
standard Network Management Framework", Internet Draft, Cisco |
Systems, September 1995. |
[8] McCloghrie, K., Editor, "Introduction to Version 2 of the |
Internet-standard Network Management Framework", Internet Draft, |
Cisco Systems, September 1995. |
16. Security Considerations
Security issues are not discussed in this memo.
17. Editor's Address
Keith McCloghrie -
Cisco Systems, Inc.
170 West Tasman Drive
San Jose, CA 95134-1706
US
Phone: +1 408 526 5260
Email: kzm@cisco.com
Table of Contents - [6] SNMPv2 Working Group, 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.
1 Introduction .................................................... 2 [7] SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M., and
1.1 A Note on Terminology ......................................... 2 S. Waldbusser, "Coexistence between Version 1 and Version 2 of the
2 Definitions ..................................................... 4 Internet-standard Network Management Framework", RFC 1908,
3.1 The MODULE-IDENTITY macro ..................................... 5 January 1996.
3.2 Object Names and Syntaxes ..................................... 7
3.3 The OBJECT-TYPE macro ......................................... 10
3.5 The NOTIFICATION-TYPE macro ................................... 12
3.6 Administrative Identifiers .................................... 12
3 Information Modules ............................................. 13
3.1 Macro Invocation .............................................. 14
3.1.1 Textual Clauses ............................................. 14
3.2 IMPORTing Symbols ............................................. 15
3.3 Exporting Symbols ............................................. 15
3.4 ASN.1 Comments ................................................ 15
3.5 OBJECT IDENTIFIER values ...................................... 15
4 Naming Hierarchy ................................................ 17
5 Mapping of the MODULE-IDENTITY macro ............................ 18
5.1 Mapping of the LAST-UPDATED clause ............................ 18
5.2 Mapping of the ORGANIZATION clause ............................ 18
5.3 Mapping of the CONTACT-INFO clause ............................ 18
5.4 Mapping of the DESCRIPTION clause ............................. 18
5.5 Mapping of the REVISION clause ................................ 19
5.5.1 Mapping of the DESCRIPTION sub-clause ....................... 19
5.6 Mapping of the MODULE-IDENTITY value .......................... 19
5.7 Usage Example ................................................. 20
6 Mapping of the OBJECT-IDENTITY macro ............................ 21
6.1 Mapping of the STATUS clause .................................. 21
6.2 Mapping of the DESCRIPTION clause ............................. 21
6.3 Mapping of the REFERENCE clause ............................... 21
6.4 Mapping of the OBJECT-IDENTITY value .......................... 21
6.5 Usage Example ................................................. 22
7 Mapping of the OBJECT-TYPE macro ................................ 23
7.1 Mapping of the SYNTAX clause .................................. 23
7.1.1 Integer32 and INTEGER ....................................... 23
7.1.2 OCTET STRING ................................................ 24
7.1.3 OBJECT IDENTIFIER ........................................... 24
7.1.4 The BITS construct .......................................... 24
7.1.5 IpAddress ................................................... 25
7.1.6 Counter32 ................................................... 25
7.1.7 Gauge32 ..................................................... 25
7.1.8 TimeTicks ................................................... 26
7.1.9 Opaque ...................................................... 26
7.1.10 Counter64 .................................................. 26
7.1.11 Unsigned32 ................................................. 27
7.1.12 Conceptual Tables .......................................... 27
7.1.12.1 Creation and Deletion of Conceptual Rows ................. 28
7.2 Mapping of the UNITS clause ................................... 28
7.3 Mapping of the MAX-ACCESS clause .............................. 28
7.4 Mapping of the STATUS clause .................................. 29
7.5 Mapping of the DESCRIPTION clause ............................. 29
7.6 Mapping of the REFERENCE clause ............................... 29
7.7 Mapping of the INDEX clause ................................... 29
7.8 Mapping of the AUGMENTS clause ................................ 31
7.8.1 Relation between INDEX and AUGMENTS clauses ................. 32
7.9 Mapping of the DEFVAL clause .................................. 32
7.10 Mapping of the OBJECT-TYPE value ............................. 33
7.11 Usage Example ................................................ 35
8 Mapping of the NOTIFICATION-TYPE macro .......................... 37
8.1 Mapping of the OBJECTS clause ................................. 37
8.2 Mapping of the STATUS clause .................................. 37
8.3 Mapping of the DESCRIPTION clause ............................. 37
8.4 Mapping of the REFERENCE clause ............................... 37
8.5 Mapping of the NOTIFICATION-TYPE value ........................ 38
8.6 Usage Example ................................................. 39
9 Refined Syntax .................................................. 40
10 Extending an Information Module ................................ 41
10.1 Object Assignments ........................................... 41
10.2 Object Definitions ........................................... 41
10.3 Notification Definitions ..................................... 42
11 Appendix A: de-OSIfying a MIB module ........................... 43
11.1 Managed Object Mapping ....................................... 43
11.1.1 Mapping to the SYNTAX clause ............................... 44
11.1.2 Mapping to the UNITS clause ................................ 45
11.1.3 Mapping to the MAX-ACCESS clause ........................... 45
11.1.4 Mapping to the STATUS clause ............................... 45
11.1.5 Mapping to the DESCRIPTION clause .......................... 45
11.1.6 Mapping to the REFERENCE clause ............................ 45
11.1.7 Mapping to the INDEX clause ................................ 45
11.1.8 Mapping to the DEFVAL clause ............................... 45
11.2 Action Mapping ............................................... 46
11.2.1 Mapping to the SYNTAX clause ............................... 46
11.2.2 Mapping to the MAX-ACCESS clause ........................... 46
11.2.3 Mapping to the STATUS clause ............................... 46
11.2.4 Mapping to the DESCRIPTION clause .......................... 46
11.2.5 Mapping to the REFERENCE clause ............................ 46
11.3 Event Mapping ................................................ 46
11.3.1 Mapping to the STATUS clause ............................... 47
11.3.2 Mapping to the DESCRIPTION clause .......................... 47
11.3.3 Mapping to the REFERENCE clause ............................ 47
12 Appendix B: UTC Time Format .................................... 48
13 Appendix C: Detailed Sub-typing Rules .......................... 49
13.1 Syntax Rules ................................................. 49
13.2 Examples ..................................................... 50
13.3 Rules for Textual Conventions ................................ 50
14 Acknowledgements ............................................... 51
15 References ..................................................... 52
16 Security Considerations ........................................ 53
17 Editor's Address ............................................... 53
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