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rfc:rfc1444
        Network Working Group                                  J. Case
        Request for Comments: 1444                 SNMP Research, Inc.
                                                         K. McCloghrie
                                                    Hughes LAN Systems
                                                               M. Rose
                                          Dover Beach Consulting, Inc.
                                                         S. Waldbusser
                                            Carnegie Mellon University
                                                            April 1993
                            Conformance Statements
                             for version 2 of the
                 Simple Network Management Protocol (SNMPv2)
        Status of this Memo
        This RFC specifes an IAB standards track protocol for the
        Internet community, and requests discussion and suggestions
        for improvements.  Please refer to the current edition of the
        "IAB Official Protocol Standards" for the standardization
        state and status of this protocol.  Distribution of this memo
        is unlimited.
        Table of Contents
        1 Introduction ..........................................    2
        1.1 A Note on Terminology ...............................    2
        2 Definitions ...........................................    3
        3.1 The OBJECT-GROUP macro ..............................    3
        3.2 The MODULE-COMPLIANCE macro .........................    4
        3.3 The AGENT-CAPABILITIES macro ........................    7
        3 Mapping of the OBJECT-GROUP macro .....................   10
        3.1 Mapping of the OBJECTS clause .......................   10
        3.2 Mapping of the STATUS clause ........................   10
        3.3 Mapping of the DESCRIPTION clause ...................   10
        3.4 Mapping of the REFERENCE clause .....................   11
        3.5 Mapping of the OBJECT-GROUP value ...................   11
        3.6 Usage Example .......................................   12
        4 Mapping of the MODULE-COMPLIANCE macro ................   13
        4.1 Mapping of the STATUS clause ........................   13
        4.2 Mapping of the DESCRIPTION clause ...................   13
        4.3 Mapping of the REFERENCE clause .....................   13
        4.4 Mapping of the MODULE clause ........................   13
        4.4.1 Mapping of the MANDATORY-GROUPS clause ............   14
        4.4.2 Mapping of the GROUP clause .......................   14
        4.4.3 Mapping of the OBJECT clause ......................   14
        Case, McCloghrie, Rose & Waldbusser                  [Page  i]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
        4.4.3.1 Mapping of the SYNTAX clause ....................   15
        4.4.3.2 Mapping of the WRITE-SYNTAX clause ..............   15
        4.4.3.3 Mapping of the MIN-ACCESS clause ................   15
        4.4.3.4 Mapping of the DESCRIPTION clause ...............   16
        4.5 Mapping of the MODULE-COMPLIANCE value ..............   16
        4.6 Usage Example .......................................   17
        5 Mapping of the AGENT-CAPABILITIES macro ...............   19
        5.1 Mapping of the PRODUCT-RELEASE clause ...............   20
        5.2 Mapping of the STATUS clause ........................   20
        5.3 Mapping of the DESCRIPTION clause ...................   20
        5.4 Mapping of the REFERENCE clause .....................   20
        5.5 Mapping of the SUPPORTS clause ......................   20
        5.5.1 Mapping of the INCLUDES clause ....................   21
        5.5.2 Mapping of the VARIATION clause ...................   21
        5.5.2.1 Mapping of the SYNTAX clause ....................   21
        5.5.2.2 Mapping of the WRITE-SYNTAX clause ..............   21
        5.5.2.3 Mapping of the ACCESS clause ....................   22
        5.5.2.4 Mapping of the CREATION-REQUIRES clause .........   22
        5.5.2.5 Mapping of the DEFVAL clause ....................   23
        5.5.2.6 Mapping of the DESCRIPTION clause ...............   23
        5.6 Mapping of the AGENT-CAPABILITIES value .............   23
        5.7 Usage Example .......................................   24
        6 Extending an Information Module .......................   26
        6.1 Conformance Groups ..................................   26
        6.2 Compliance Definitions ..............................   26
        6.3 Capabilities Definitions ............................   26
        7 Acknowledgements ......................................   27
        8 References ............................................   31
        9 Security Considerations ...............................   32
        10 Authors' Addresses ...................................   32
        Case, McCloghrie, Rose & Waldbusser                   [Page 1]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
        1.  Introduction
        A network management system contains: several (potentially
        many) nodes, each with a processing entity, termed an agent,
        which has access to management instrumentation; at least one
        management station; and, a management protocol, used to convey
        management information between the agents and management
        stations.  Operations of the protocol are carried out under an
        administrative framework which defines both authentication and
        authorization policies.
        Network management stations execute management applications
        which monitor and control network elements.  Network elements
        are devices such as hosts, routers, terminal servers, etc.,
        which are monitored and controlled through access to their
        management information.
        Management information is viewed as a collection of managed
        objects, residing in a virtual information store, termed the
        Management Information Base (MIB).  Collections of related
        objects are defined in MIB modules.  These modules are written
        using a subset of OSI's Abstract Syntax Notation One (ASN.1)
        [1], termed the Structure of Management Information (SMI) [2].
        It may be useful to define the acceptable lower-bounds of
        implementation, along with the actual level of implementation
        achieved.  It is the purpose of this document to define the
        notation used for these purposes.
        1.1.  A Note on Terminology
        For the purpose of exposition, the original Internet-standard
        Network Management Framework, as described in RFCs 1155, 1157,
        and 1212, is termed the SNMP version 1 framework (SNMPv1).
        The current framework is termed the SNMP version 2 framework
        (SNMPv2).
        Case, McCloghrie, Rose & Waldbusser                   [Page 2]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
        2.  Definitions
        SNMPv2-CONF DEFINITIONS ::= BEGIN
  1. - definitions for conformance groups
        OBJECT-GROUP MACRO ::=
        BEGIN
            TYPE NOTATION ::=
                          ObjectsPart
                          "STATUS" Status
                          "DESCRIPTION" Text
                          ReferPart
            VALUE NOTATION ::=
                          value(VALUE OBJECT IDENTIFIER)
            ObjectsPart ::=
                          "OBJECTS" "{" Objects "}"
            Objects ::=
                          Object
                        | Objects "," Object
            Object ::=
                          value(Name ObjectName)
            Status ::=
                          "current"
                        | "obsolete"
            ReferPart ::=
                          "REFERENCE" Text
                        | empty
  1. - uses the NVT ASCII character set

Text ::= """" string """"

        END
        Case, McCloghrie, Rose & Waldbusser                   [Page 3]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
  1. - definitions for compliance statements
        MODULE-COMPLIANCE MACRO ::=
        BEGIN
            TYPE NOTATION ::=
                          "STATUS" Status
                          "DESCRIPTION" Text
                          ReferPart
                          ModulePart
            VALUE NOTATION ::=
                          value(VALUE OBJECT IDENTIFIER)
            Status ::=
                          "current"
                        | "obsolete"
            ReferPart ::=
                        "REFERENCE" Text
                      | empty
            ModulePart ::=
                          Modules
                        | empty
            Modules ::=
                          Module
                        | Modules Module
            Module ::=
                          -- name of module --
                          "MODULE" ModuleName
                          MandatoryPart
                          CompliancePart
            ModuleName ::=
                          modulereference ModuleIdentifier
                        -- must not be empty unless contained
                        -- in MIB Module
                        | empty
            ModuleIdentifier ::=
                          value(ModuleID OBJECT IDENTIFIER)
                        | empty
            MandatoryPart ::=
                          "MANDATORY-GROUPS" "{" Groups "}"
                        | empty
        Case, McCloghrie, Rose & Waldbusser                   [Page 4]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
            Groups ::=
                          Group
                        | Groups "," Group
            Group ::=
                          value(Group OBJECT IDENTIFIER)
            CompliancePart ::=
                          Compliances
                        | empty
            Compliances ::=
                          Compliance
                        | Compliances Compliance
            Compliance ::=
                          ComplianceGroup
                        | Object
            ComplianceGroup ::=
                          "GROUP" value(Name OBJECT IDENTIFIER)
                          "DESCRIPTION" Text
            Object ::=
                          "OBJECT" value(Name ObjectName)
                          SyntaxPart
                          WriteSyntaxPart
                          AccessPart
                          "DESCRIPTION" Text
  1. - must be a refinement for object's SYNTAX clause

SyntaxPart ::=

                          "SYNTAX" type(SYNTAX)
                        | empty
  1. - must be a refinement for object's SYNTAX clause

WriteSyntaxPart ::=

                          "WRITE-SYNTAX" type(WriteSYNTAX)
                        | empty
            AccessPart ::=
                          "MIN-ACCESS" Access
                        | empty
            Access ::=
                          "not-accessible"
                        | "read-only"
                        | "read-write"
        Case, McCloghrie, Rose & Waldbusser                   [Page 5]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
                        | "read-create"
  1. - uses the NVT ASCII character set

Text ::= """" string """"

        END
        Case, McCloghrie, Rose & Waldbusser                   [Page 6]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
  1. - definitions for capabilities statements
        AGENT-CAPABILITIES MACRO ::=
        BEGIN
            TYPE NOTATION ::=
                          "PRODUCT-RELEASE" Text
                          "STATUS" Status
                          "DESCRIPTION" Text
                          ReferPart
                          ModulePart
            VALUE NOTATION ::=
                          -- agent's sysObjectID [3] or snmpORID [4]
                          value(VALUE OBJECT IDENTIFIER)
            Status ::=
                          "current"
                        | "obsolete"
            ReferPart ::=
                        "REFERENCE" Text
                      | empty
            ModulePart ::=
                          Modules
                        | empty
            Modules ::=
                          Module
                        | Modules Module
            Module ::=
                          -- name of module --
                          "SUPPORTS" ModuleName
                          "INCLUDES" "{" Groups "}"
                          VariationPart
            ModuleName ::=
                          identifier ModuleIdentifier
            ModuleIdentifier ::=
                          value(ModuleID OBJECT IDENTIFIER)
                        | empty
            Groups ::=
                          Group
                        | Groups "," Group
            Group ::=
        Case, McCloghrie, Rose & Waldbusser                   [Page 7]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
                          value(Name OBJECT IDENTIFIER)
            VariationPart ::=
                          Variations
                        | empty
            Variations ::=
                          Variation
                        | Variations Variation
            Variation ::=
                          "VARIATION" value(Name ObjectName)
                          SyntaxPart
                          WriteSyntaxPart
                          AccessPart
                          CreationPart
                          DefValPart
                          "DESCRIPTION" Text
  1. - must be a refinement for object's SYNTAX clause

SyntaxPart ::=

                          "SYNTAX" type(SYNTAX)
                        | empty
  1. - must be a refinement for object's SYNTAX clause

WriteSyntaxPart ::=

                          "WRITE-SYNTAX" type(WriteSYNTAX)
                        | empty
            AccessPart ::=
                          "ACCESS" Access
                        | empty
            Access ::=
                          "not-implemented"
                        | "read-only"
                        | "read-write"
                        | "read-create"
                        -- following is for backward-compatibility only
                        | "write-only"
            CreationPart ::=
                          "CREATION-REQUIRES" "{" Cells "}"
                        | empty
            Cells ::=
        Case, McCloghrie, Rose & Waldbusser                   [Page 8]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
                          Cell
                        | Cells "," Cell
            Cell ::=
                          value(Cell ObjectName)
            DefValPart ::=
                          "DEFVAL" "{" value(Defval ObjectSyntax) "}"
                        | empty
  1. - uses the NVT ASCII character set

Text ::= """" string """"

        END
        END
        Case, McCloghrie, Rose & Waldbusser                   [Page 9]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
        3.  Mapping of the OBJECT-GROUP macro
        For conformance purposes, it is useful to define a collection
        of related managed objects.  The OBJECT-GROUP macro is used to
        define each such collection of related objects.  It should be
        noted that the expansion of the OBJECT-GROUP macro is
        something which conceptually happens during implementation and
        not during run-time.
        To "implement" an object, a SNMPv2 entity acting in an agent
        role must return a reasonably accurate value for management
        protocol retrieval operations; similarly, if the object is
        writable, then in response to a management protocol set
        operation, a SNMPv2 entity must accordingly be able to
        reasonably influence the underlying managed entity.  If a
        SNMPv2 entity acting in an agent role can not implement an
        object, the management protocol provides for the SNMPv2 entity
        to return an exception or error, e.g, noSuchObject [6].  Under
        no circumstances shall a SNMPv2 entity return a value for
        objects which it does not implement -- it must always return
        the appropriate exception or error, as described in the
        protocol specification [6].
        3.1.  Mapping of the OBJECTS clause
        The OBJECTS clause which must be present, is used to name each
        object contained in the conformance group.  Each of the named
        objects must be defined in the same information module as the
        OBJECT-GROUP macro appears, and must have a MAX-ACCESS clause
        value of "read-only", "read-write", or "read-create".
        3.2.  Mapping of the STATUS clause
        The STATUS clause, which must be present, indicates whether
        this definition is current or historic.
        The values "current", and "obsolete" are self-explanatory.
        3.3.  Mapping of the DESCRIPTION clause
        The DESCRIPTION clause, which must be present, contains a
        textual definition of that group, along with a description of
        Case, McCloghrie, Rose & Waldbusser                  [Page 10]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
        any relations to other groups.  Note that generic compliance
        requirements should not be stated in this clause.  However,
        implementation relationships between this group and other
        groups may be defined in this clause.
        3.4.  Mapping of the REFERENCE clause
        The REFERENCE clause, which need not be present, contains a
        textual cross-reference to a group  defined in some other
        information module.  This is useful when de-osifying a MIB
        module produced by some other organization.
        3.5.  Mapping of the OBJECT-GROUP value
        The value of an invocation of the OBJECT-GROUP macro is the
        name of the group, which is an OBJECT IDENTIFIER, an
        administratively assigned name.
        Case, McCloghrie, Rose & Waldbusser                  [Page 11]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
        3.6.  Usage Example
        Consider how the system group from MIB-II [3] might be
        described:
        systemGroup OBJECT-GROUP
            OBJECTS     { sysDescr, sysObjectID, sysUpTime,
                          sysContact, sysName, sysLocation,
                          sysServices }
            STATUS  current
            DESCRIPTION
                    "The system group defines objects which are common
                    to all managed systems."
            ::= { mibIIGroups 1 }
        According to this invocation, the conformance group named
             { mibIIGroups 1 }
        contains 7 objects.
        Case, McCloghrie, Rose & Waldbusser                  [Page 12]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
        4.  Mapping of the MODULE-COMPLIANCE macro
        The MODULE-COMPLIANCE macro is used to convey a minimum set of
        requirements with respect to implementation of one or more MIB
        modules.  It should be noted that the expansion of the
        MODULE-COMPLIANCE macro is something which conceptually
        happens during implementation and not during run-time.
        A requirement on all "standard" MIB modules is that a
        corresponding MODULE-COMPLIANCE specification is also defined,
        either in the same information module or in a companion
        information module.
        4.1.  Mapping of the STATUS clause
        The STATUS clause, which must be present, indicates whether
        this definition is current or historic.
        The values "current", and "obsolete" are self-explanatory.
        The "deprecated" value indicates that that object is obsolete,
        but that an implementor may wish to support that object to
        foster interoperability with older implementations.
        4.2.  Mapping of the DESCRIPTION clause
        The DESCRIPTION clause, which must be present, contains a
        textual definition of this compliance statement and should
        embody any information which would otherwise be communicated
        in any ASN.1 commentary annotations associated with the
        statement.
        4.3.  Mapping of the REFERENCE clause
        The REFERENCE clause, which need not be present, contains a
        textual cross-reference to a compliance statement defined in
        some other information module.
        4.4.  Mapping of the MODULE clause
        The MODULE clause, which must be present, is repeatedly used
        to name each MIB module for which compliance requirements are
        Case, McCloghrie, Rose & Waldbusser                  [Page 13]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
        being specified.  Each MIB module is named by its module name,
        and optionally, by its associated OBJECT IDENTIFIER as well.
        The module name can be omitted when the MODULE-COMPLIANCE
        invocation occurs inside a MIB module, to refer to the
        encompassing MIB module.
        4.4.1.  Mapping of the MANDATORY-GROUPS clause
        The MANDATORY-GROUPS clause, which need not be present, names
        the one or more groups within the correspondent MIB module
        which are unconditionally mandatory for implementation.  If a
        SNMPv2 entity acting in an agent role claims compliance to the
        MIB module, then it must implement each and every object
        within each conformance group listed.  That is, if a SNMPv2
        entity returns a noSuchObject exception in response to a
        management protocol get operation [5] for any object within
        any mandatory conformance group for every MIB view, then that
        SNMPv2 entity is not a conformant implementation of the MIB
        module.
        4.4.2.  Mapping of the GROUP clause
        The GROUP clause which need not be present, is repeatedly used
        to name each MIB group which is conditionally mandatory or
        unconditionally optional for compliance to the MIB module.  A
        MIB group named in a GROUP clause must be absent from the
        correspondent MANDATORY-GROUPS clause.
        Conditionally mandatory groups include those which are
        mandatory only if a particular protocol is implemented, or
        only if another group is implemented.  A GROUP clause's
        DESCRIPTION specifies the conditions under which the group is
        conditionally mandatory.
        A MIB group which is named in neither a MANDATORY-GROUPS
        clause nor a GROUP clause, is unconditionally optional for
        compliance to the MIB module.
        4.4.3.  Mapping of the OBJECT clause
        The OBJECT clause which need not be present, is repeatedly
        used to name each MIB object for which compliance has a
        Case, McCloghrie, Rose & Waldbusser                  [Page 14]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
        refined requirement with respect to the MIB module definition.
        The MIB object must be present in one of the conformance
        groups named in the correspondent MANDATORY-GROUPS clause or
        GROUP clauses.
        4.4.3.1.  Mapping of the SYNTAX clause
        The SYNTAX clause, which need not be present, is used to
        provide a refined SYNTAX for the object named in the
        correspondent OBJECT clause.  Note that if this clause and a
        WRITE-SYNTAX clause are both present, then this clause only
        applies when instances of the object named in the
        correspondent OBJECT clause are read.
        Consult Section 10 of [2] for more information on refined
        syntax.
        4.4.3.2.  Mapping of the WRITE-SYNTAX clause
        The WRITE-SYNTAX clause, which need not be present, is used to
        provide a refined SYNTAX for the object named in the
        correspondent OBJECT clause when instances of that object are
        written.
        Consult Section 10 of [2] for more information on refined
        syntax.
        4.4.3.3.  Mapping of the MIN-ACCESS clause
        The MIN-ACCESS clause, which need not be present, is used to
        define the minimal level of access for the object named in the
        correspondent OBJECT clause.  If this clause is absent, the
        minimal level of access is the same as the maximal level
        specified in the correspondent invocation of the OBJECT-TYPE
        macro.  If present, this clause must not specify a greater
        level of access than is specified in the correspondent
        invocation of the OBJECT-TYPE macro.
        The level of access for certain types of objects is fixed
        according to their syntax definition.  These types are:
        conceptual tables and rows, auxiliary objects, and objects
        with the syntax of Counter32, Counter64, or certain types of
        Case, McCloghrie, Rose & Waldbusser                  [Page 15]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
        textual conventions (e.g., RowStatus [6]).  A MIN-ACCESS
        clause should not be present for such objects.
        An implementation is compliant if the level of access it
        provides is greater or equal to the minimal level in the
        MODULE-COMPLIANCE macro and less or equal to the maximal level
        in the OBJECT-TYPE macro.
        4.4.3.4.  Mapping of the DESCRIPTION clause
        The DESCRIPTION clause must be present for each use of the
        GROUP or OBJECT clause.  For an OBJECT clause, it contains a
        textual description of the refined compliance requirement.
        For a GROUP clause, it contains a textual description of the
        conditions under which the group is conditionally mandatory or
        unconditionally optional.
        4.5.  Mapping of the MODULE-COMPLIANCE value
        The value of an invocation of the MODULE-COMPLIANCE macro is
        an OBJECT IDENTIFIER.  As such, this value may be
        authoritatively used when referring to the compliance
        statement embodied by that invocation of the macro.
        Case, McCloghrie, Rose & Waldbusser                  [Page 16]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
        4.6.  Usage Example
        Consider how a compliance statement might be included at the
        end of the MIB-II document [3], assuming that conformance
        groups were defined therein:
        mibIICompliances
                       OBJECT IDENTIFIER ::= { mibIIConformance 1 }
        mibIIGroups    OBJECT IDENTIFIER ::= { mibIIConformance 2 }
        mibIICompliance MODULE-COMPLIANCE
            STATUS  current
            DESCRIPTION
                    "The compliance statement for SNMPv2 entities
                    residing on systems which implement the Internet
                    suite of protocols."
            MODULE  -- compliance to the containing MIB module
                MANDATORY-GROUPS   { systemGroup, snmpGroup }
                GROUP       interfacesGroup
                DESCRIPTION
                    "The interfaces group is mandatory for systems
                    with network interfaces."
                GROUP       ipGroup
                DESCRIPTION
                    "The ip group is mandatory for systems which
                    implement IP."
                GROUP       icmpGroup
                DESCRIPTION
                    "The icmp group is mandatory for systems which
                    implement ICMP."
                GROUP       tcpGroup
                DESCRIPTION
                    "The tcp group is mandatory for systems which
                    implement TCP."
                    OBJECT      tcpConnState
                    MIN-ACCESS  read-only
                    DESCRIPTION
                        "A compliant system need not allow
                         write-access to this object."
                GROUP       udpGroup
        Case, McCloghrie, Rose & Waldbusser                  [Page 17]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
                DESCRIPTION
                    "The udp group is mandatory for systems which
                    implement UDP."
                GROUP       egpGroup
                DESCRIPTION
                    "The egp group is mandatory for systems which
                    implement EGP."
        ::= { mibIICompliances 1 }
        According to this invocation, to claim alignment with the
        compliance statement named
             { mibIICompliances 1 }
        a system must implement RFC1213's systemGroup and snmpGroup
        conformance groups.  If the system implements any network
        interfaces, then RFC1213's interfacesGroup conformance group
        must be implemented.  Further, if the system implements any of
        the IP, ICMP, TCP, UDP, or EGP protocols, then the
        correspondent conformance group in RFC1213 must be
        implemented, if compliance is to be claimed.  Finally,
        although RFC1213 specifies that it makes "protocol sense" for
        the tcpConnState object to be writable, this specification
        allows the system to permit only read-only access and still
        claim compliance.
        Case, McCloghrie, Rose & Waldbusser                  [Page 18]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
        5.  Mapping of the AGENT-CAPABILITIES macro
        The AGENT-CAPABILITIES macro is used to convey the
        capabilities present in a SNMPv2 entity acting in an agent
        role.  It should be noted that the expansion of the AGENT-
        CAPABILITIES macro is something which conceptually happens
        during implementation and not during run-time.
        When a MIB module is written, it is divided into units of
        conformance termed groups.  If a SNMPv2 entity acting in an
        agent role claims to implement a group, then it must implement
        each and every object within that group.  Of course, for
        whatever reason, a SNMPv2 entity might implement only a subset
        of the groups within a MIB module.  In addition, the
        definition of some MIB objects leave some aspects of the
        definition to the discretion of an implementor.
        Practical experience has demonstrated a need for concisely
        describing the capabilities of an agent with respect to one or
        more MIB modules.  The AGENT-CAPABILITIES macro allows an
        agent implementor to describe the precise level of support
        which an agent claims in regards to a MIB group, and to bind
        that description to the value of sysObjectID [3] associated
        with the agent, or to the value of an instance of the snmpORID
        object in the snmpORTable [4].  In particular, some objects
        may have restricted or augmented syntax or access-levels.
        If the AGENT-CAPABILITIES invocation is given to a
        management-station implementor, then that implementor can
        build management applications which optimize themselves when
        communicating with a particular agent.  For example, the
        management-station can maintain a database of these
        invocations.  When a management-station interacts with an
        agent, it retrieves the agent's sysObjectID [3].  Based on
        this, it consults the database.  If an entry is found, then
        the management application can optimize its behavior
        accordingly.
        Note that this binding to sysObjectID may not always suffice
        to define all MIB objects to which an agent can provide
        access.  In particular, this situation occurs where the agent
        dynamically learns of the objects it supports.  In these
        cases, the snmpORID column of snmpORTable [4] contains
        information which should be used in addition to sysObjectID.
        Case, McCloghrie, Rose & Waldbusser                  [Page 19]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
        Note that the AGENT-CAPABILITIES macro specifies refinements
        or variations with respect to OBJECT-TYPE macros in MIB
        modules, NOT with respect to MODULE-COMPLIANCE macros in
        compliance statements.
        5.1.  Mapping of the PRODUCT-RELEASE clause
        The PRODUCT-RELEASE clause, which must be present, contains a
        textual description of the product release which includes this
        agent.
        5.2.  Mapping of the STATUS clause
        The STATUS clause, which must be present, indicates whether
        this definition is current or historic.
        The values "current", and "obsolete" are self-explanatory.
        The "deprecated" value indicates that that object is obsolete,
        but that an implementor may wish to support that object to
        foster interoperability with older implementations.
        5.3.  Mapping of the DESCRIPTION clause
        The DESCRIPTION clause, which must be present, contains a
        textual description of this agent.
        5.4.  Mapping of the REFERENCE clause
        The REFERENCE clause, which need not be present, contains a
        textual cross-reference to a capability statement defined in
        some other information module.
        5.5.  Mapping of the SUPPORTS clause
        The SUPPORTS clause, which need not be present, is repeatedly
        used to name each MIB module for which the agent claims a
        complete or partial implementation.  Each MIB module is named
        by its module name, and optionally, by its associated OBJECT
        IDENTIFIER as well.
        Case, McCloghrie, Rose & Waldbusser                  [Page 20]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
        5.5.1.  Mapping of the INCLUDES clause
        The INCLUDES clause, which must be present for each use of the
        SUPPORTS clause, is used to name each MIB group associated
        with the SUPPORT clause, which the agent claims to implement.
        5.5.2.  Mapping of the VARIATION clause
        The VARIATION clause, which need not be present, is repeatedly
        used to name each MIB object which the agent implements in
        some variant or refined fashion with respect to the
        correspondent invocation of the OBJECT-TYPE macro.
        Note that the variation concept is meant for generic
        implementation restrictions, e.g., if the variation for an
        object depends on the values of other objects, then this
        should be noted in the appropriate DESCRIPTION clause.
        5.5.2.1.  Mapping of the SYNTAX clause
        The SYNTAX clause, which need not be present, is used to
        provide a refined SYNTAX for the object named in the
        correspondent VARIATION clause.  Note that if this clause and
        a WRITE-SYNTAX clause are both present, then this clause only
        applies when instances of the object named in the
        correspondent VARIATION clause are read.
        Consult Section 10 of [2] for more information on refined
        syntax.
        5.5.2.2.  Mapping of the WRITE-SYNTAX clause
        The WRITE-SYNTAX clause, which need not be present, is used to
        provide a refined SYNTAX for the object named in the
        correspondent VARIATION clause when instances of that object
        are written.
        Consult Section 10 of [2] for more information on refined
        syntax.
        Case, McCloghrie, Rose & Waldbusser                  [Page 21]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
        5.5.2.3.  Mapping of the ACCESS clause
        The ACCESS clause, which need not be present, is used to
        indicate the agent provides less than the maximal level of
        access to the object named in the correspondent VARIATION
        clause.
        The value "not-implemented" indicates the agent does not
        implement the object, and in the ordering of possible values
        is equivalent to "not-accessible".
        The value "write-only" is provided solely for backward
        compatibility, and shall not be used for newly-defined object
        types.  In the ordering of possible values, "write-only" is
        less than "not-accessible".
        5.5.2.4.  Mapping of the CREATION-REQUIRES clause
        The CREATION-REQUIRES clause, which need not be present, is
        used to name the columnar objects of a conceptual row to which
        values must be explicitly assigned, by a management protocol
        set operation, before the agent will allow the instance of the
        status column of that row to be set to `active'.  (Consult the
        definition of RowStatus [6].)
        If the conceptual row does not have a status column (i.e., the
        objects corresponding to the conceptual table were defined
        using the mechanisms in [7,8]), then the CREATION-REQUIRES
        clause, which need not be present, is used to name the
        columnar objects of a conceptual row to which values must be
        explicitly assigned, by a management protocol set operation,
        before the agent will create new instances of objects in that
        row.
        This clause must not present unless the object named in the
        correspondent VARIATION clause is a conceptual row, i.e., has
        a syntax which resolves to a SEQUENCE containing columnar
        objects.  The objects named in the value of this clause
        usually will refer to columnar objects in that row.  However,
        objects unrelated to the conceptual row may also be specified.
        All objects which are named in the CREATION-REQUIRES clause
        for a conceptual row, and which are columnar objects of that
        row, must have an access level of "read-create".
        Case, McCloghrie, Rose & Waldbusser                  [Page 22]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
        5.5.2.5.  Mapping of the DEFVAL clause
        The DEFVAL clause, which need not be present, is used to
        provide a refined DEFVAL value for the object named in the
        correspondent VARIATION clause.  The semantics of this value
        are identical to those of the OBJECT-TYPE macro's DEFVAL
        clause.
        5.5.2.6.  Mapping of the DESCRIPTION clause
        The DESCRIPTION clause, which must be present for each use of
        the VARIATION clause, contains a textual description of the
        variant or refined implementation.
        5.6.  Mapping of the AGENT-CAPABILITIES value
        The value of an invocation of the AGENT-CAPABILITIES macro is
        an OBJECT IDENTIFIER, which names the value of sysObjectID [3]
        or snmpORID [4] for which this capabilities statement is
        valid.
        Case, McCloghrie, Rose & Waldbusser                  [Page 23]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
        5.7.  Usage Example
        Consider how a capabilities statement for an agent might be
        described:
        exampleAgent AGENT-CAPABILITIES
            PRODUCT-RELEASE      "ACME Agent release 1.1 for 4BSD"
            STATUS               current
            DESCRIPTION          "ACME agent for 4BSD"
            SUPPORTS             RFC1213-MIB
                INCLUDES         { systemGroup, interfacesGroup,
                                   atGroup, ipGroup, icmpGroup,
                                   tcpGroup, udpGroup, snmpGroup }
                VARIATION        ifAdminStatus
                    SYNTAX       INTEGER { up(1), down(2) }
                    DESCRIPTION  "Unable to set test mode on 4BSD"
                VARIATION        ifOperStatus
                    SYNTAX       INTEGER { up(1), down(2) }
                    DESCRIPTION  "Information limited on 4BSD"
                VARIATION        atEntry
                    CREATION-REQUIRES { atPhysAddress }
                    DESCRIPTION  "Address mappings on 4BSD require
                                 both protocol and media addresses"
                VARIATION        ipDefaultTTL
                    SYNTAX       INTEGER (255..255)
                    DESCRIPTION  "Hard-wired on 4BSD"
                VARIATION        ipInAddrErrors
                    ACCESS       not-implemented
                    DESCRIPTION  "Information not available on 4BSD"
                VARIATION        ipRouteType
                    SYNTAX       INTEGER { direct(3), indirect(4) }
                    WRITE-SYNTAX INTEGER { invalid(2), direct(3),
                                           indirect(4) }
                    DESCRIPTION  "Information limited on 4BSD"
                VARIATION        tcpConnState
                    ACCESS       read-only
                    DESCRIPTION  "Unable to set this on 4BSD"
        Case, McCloghrie, Rose & Waldbusser                  [Page 24]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
            SUPPORTS             EVAL-MIB
                INCLUDES         { functionsGroup, expressionsGroup }
                VARIATION        exprEntry
                    CREATION-REQUIRES { evalString }
                    DESCRIPTION "Conceptual row creation supported"
            ::= { acmeAgents 1 }
        According to this invocation, an agent with a sysObjectID (or
        snmpORID) value of
             { acmeAgents 1 }
        supports two MIB modules.
        From MIB-II, all conformance groups except the egpGroup
        conformance group are supported.  However, the object
        ipInAddrErrors is not implemented, whilst the objects
             ifAdminStatus
             ifOperStatus
             ipDefaultTTL
             ipRouteType
        have a restricted syntax, and the object
             tcpConnState
        is available only for reading.  Note that in the case of the
        object ipRouteType the set of values which may be read is
        different than the set of values which may be written.
        Finally, when creating a new instance in the atTable, the
        set-request must create an instance of atPhysAddress.
        From the EVAL-MIB, all the objects contained in the
        functionsGroup and expressionsGroup conformance groups are
        supported, without variation.  In addition, creation of new
        instances in the expr table is supported.
        Case, McCloghrie, Rose & Waldbusser                  [Page 25]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
        6.  Extending an Information Module
        As experience is gained with a published information module,
        it may be desirable to revise that information module.
        Section 10 of [2] defines the rules for extending an
        information module.  The remainder of this section defines how
        conformance groups, compliance statements, and capabilities
        statements may be extended.
        6.1.  Conformance Groups
        If any non-editorial change is made to any clause of an object
        group then the OBJECT IDENTIFIER value associated with that
        object group must also be changed, along with its associated
        descriptor.
        6.2.  Compliance Definitions
        If any non-editorial change is made to any clause of a
        compliance definition, then the OBJECT IDENTIFIER value
        associated with that compliance definition must also be
        changed, along with its associated descriptor.
        6.3.  Capabilities Definitions
        If any non-editorial change is made to any clause of a
        capabilities definition, then the OBJECT IDENTIFIER value
        associated with that capabilities definition must also be
        changed, along with its associated descriptor.
        Case, McCloghrie, Rose & Waldbusser                  [Page 26]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
        7.  Acknowledgements
        The section on compliance statements is based, in part, on a
        conversation with James R. Davin in December, 1990.
        The section on capabilities statements is based, in part, on
        RFC 1303.
        Finally, the comments of the SNMP version 2 working group are
        gratefully acknowledged:
             Beth Adams, Network Management Forum
             Steve Alexander, INTERACTIVE Systems Corporation
             David Arneson, Cabletron Systems
             Toshiya Asaba
             Fred Baker, ACC
             Jim Barnes, Xylogics, Inc.
             Brian Bataille
             Andy Bierman, SynOptics Communications, Inc.
             Uri Blumenthal, IBM Corporation
             Fred Bohle, Interlink
             Jack Brown
             Theodore Brunner, Bellcore
             Stephen F. Bush, GE Information Services
             Jeffrey D. Case, University of Tennessee, Knoxville
             John Chang, IBM Corporation
             Szusin Chen, Sun Microsystems
             Robert Ching
             Chris Chiotasso, Ungermann-Bass
             Bobby A. Clay, NASA/Boeing
             John Cooke, Chipcom
             Tracy Cox, Bellcore
             Juan Cruz, Datability, Inc.
             David Cullerot, Cabletron Systems
             Cathy Cunningham, Microcom
             James R. (Chuck) Davin, Bellcore
             Michael Davis, Clearpoint
             Mike Davison, FiberCom
             Cynthia DellaTorre, MITRE
             Taso N. Devetzis, Bellcore
             Manual Diaz, DAVID Systems, Inc.
             Jon Dreyer, Sun Microsystems
             David Engel, Optical Data Systems
             Mike Erlinger, Lexcel
             Roger Fajman, NIH
        Case, McCloghrie, Rose & Waldbusser                  [Page 27]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
             Daniel Fauvarque, Sun Microsystems
             Karen Frisa, CMU
             Shari Galitzer, MITRE
             Shawn Gallagher, Digital Equipment Corporation
             Richard Graveman, Bellcore
             Maria Greene, Xyplex, Inc.
             Michel Guittet, Apple
             Robert Gutierrez, NASA
             Bill Hagerty, Cabletron Systems
             Gary W. Haney, Martin Marietta Energy Systems
             Patrick Hanil, Nokia Telecommunications
             Matt Hecht, SNMP Research, Inc.
             Edward A. Heiner, Jr., Synernetics Inc.
             Susan E. Hicks, Martin Marietta Energy Systems
             Geral Holzhauer, Apple
             John Hopprich, DAVID Systems, Inc.
             Jeff Hughes, Hewlett-Packard
             Robin Iddon, Axon Networks, Inc.
             David Itusak
             Kevin M. Jackson, Concord Communications, Inc.
             Ole J. Jacobsen, Interop Company
             Ronald Jacoby, Silicon Graphics, Inc.
             Satish Joshi, SynOptics Communications, Inc.
             Frank Kastenholz, FTP Software
             Mark Kepke, Hewlett-Packard
             Ken Key, SNMP Research, Inc.
             Zbiginew Kielczewski, Eicon
             Jongyeoi Kim
             Andrew Knutsen, The Santa Cruz Operation
             Michael L. Kornegay, VisiSoft
             Deirdre C. Kostik, Bellcore
             Cheryl Krupczak, Georgia Tech
             Mark S. Lewis, Telebit
             David Lin
             David Lindemulder, AT&T/NCR
             Ben Lisowski, Sprint
             David Liu, Bell-Northern Research
             John Lunny, The Wollongong Group
             Robert C. Lushbaugh Martin, Marietta Energy Systems
             Michael Luufer, BBN
             Carl Madison, Star-Tek, Inc.
             Keith McCloghrie, Hughes LAN Systems
             Evan McGinnis, 3Com Corporation
             Bill McKenzie, IBM Corporation
             Donna McMaster, SynOptics Communications, Inc.
        Case, McCloghrie, Rose & Waldbusser                  [Page 28]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
             John Medicke, IBM Corporation
             Doug Miller, Telebit
             Dave Minnich, FiberCom
             Mohammad Mirhakkak, MITRE
             Rohit Mital, Protools
             George Mouradian, AT&T Bell Labs
             Patrick Mullaney, Cabletron Systems
             Dan Myers, 3Com Corporation
             Rina Nathaniel, Rad Network Devices Ltd.
             Hien V. Nguyen, Sprint
             Mo Nikain
             Tom Nisbet
             William B. Norton, MERIT
             Steve Onishi, Wellfleet Communications, Inc.
             David T. Perkins, SynOptics Communications, Inc.
             Carl Powell, BBN
             Ilan Raab, SynOptics Communications, Inc.
             Richard Ramons, AT&T
             Venkat D. Rangan, Metric Network Systems, Inc.
             Louise Reingold, Sprint
             Sam Roberts, Farallon Computing, Inc.
             Kary Robertson, Concord Communications, Inc.
             Dan Romascanu, Lannet Data Communications Ltd.
             Marshall T. Rose, Dover Beach Consulting, Inc.
             Shawn A. Routhier, Epilogue Technology Corporation
             Chris Rozman
             Asaf Rubissa, Fibronics
             Jon Saperia, Digital Equipment Corporation
             Michael Sapich
             Mike Scanlon, Interlan
             Sam Schaen, MITRE
             John Seligson, Ultra Network Technologies
             Paul A. Serice, Corporation for Open Systems
             Chris Shaw, Banyan Systems
             Timon Sloane
             Robert Snyder, Cisco Systems
             Joo Young Song
             Roy Spitier, Sprint
             Einar Stefferud, Network Management Associates
             John Stephens, Cayman Systems, Inc.
             Robert L. Stewart, Xyplex, Inc. (chair)
             Kaj Tesink, Bellcore
             Dean Throop, Data General
             Ahmet Tuncay, France Telecom-CNET
             Maurice Turcotte, Racal Datacom
        Case, McCloghrie, Rose & Waldbusser                  [Page 29]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
             Warren Vik, INTERACTIVE Systems Corporation
             Yannis Viniotis
             Steven L. Waldbusser, Carnegie Mellon Universitty
             Timothy M. Walden, ACC
             Alice Wang, Sun Microsystems
             James Watt, Newbridge
             Luanne Waul, Timeplex
             Donald E. Westlake III, Digital Equipment Corporation
             Gerry White
             Bert Wijnen, IBM Corporation
             Peter Wilson, 3Com Corporation
             Steven Wong, Digital Equipment Corporation
             Randy Worzella, IBM Corporation
             Daniel Woycke, MITRE
             Honda Wu
             Jeff Yarnell, Protools
             Chris Young, Cabletron
             Kiho Yum, 3Com Corporation
        Case, McCloghrie, Rose & Waldbusser                  [Page 30]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
        8.  References
        [1]  Information processing systems - Open Systems
             Interconnection - Specification of Abstract Syntax
             Notation One (ASN.1), International Organization for
             Standardization.  International Standard 8824, (December,
             1987).
        [2]  Case, J., McCloghrie, K., Rose, M., and Waldbusser, S.,
             "Structure of Management Information for version 2 of the
             Simple Network Management Protocol (SNMPv2)", RFC 1442,
             SNMP Research, Inc., Hughes LAN Systems, Dover Beach
             Consulting, Inc., Carnegie Mellon University, April 1993.
        [3]  McCloghrie, K., and Rose, M., "Management Information
             Base for Network Management of TCP/IP-based internets:
             MIB-II", STD 17, RFC 1213, March 1991.
        [4]  Case, J., McCloghrie, K., Rose, M., and Waldbusser, S.,
             "Management Information Base for version 2 of the Simple
             Network Management Protocol (SNMPv2)", RFC 1450, SNMP
             Research, Inc., Hughes LAN Systems, Dover Beach
             Consulting, Inc., Carnegie Mellon University, April 1993.
        [5]  Case, J., McCloghrie, K., Rose, M., and Waldbusser, S.,
             "Protocol Operations for version 2 of the Simple Network
             Management Protocol (SNMPv2)", RFC 1448, SNMP Research,
             Inc., Hughes LAN Systems, Dover Beach Consulting, Inc.,
             Carnegie Mellon University, April 1993.
        [6]  Case, J., McCloghrie, K., Rose, M., and Waldbusser, S.,
             "Textual Conventions for version 2 of the the Simple
             Network Management Protocol (SNMPv2)", RFC 1443, SNMP
             Research, Inc., Hughes LAN Systems, Dover Beach
             Consulting, Inc., Carnegie Mellon University, April 1993.
        [7]  Rose, M., and McCloghrie, K., "Structure and
             Identification of Management Information for TCP/IP-based
             internets", STD 16, RFC 1155, May 1990.
        [8]  Rose, M., and McCloghrie, K., "Concise MIB Definitions",
             STD 16, RFC 1212, March 1991.
        Case, McCloghrie, Rose & Waldbusser                  [Page 31]
        RFC 1444      Conformance Statements for SNMPv2     April 1993
        9.  Security Considerations
        Security issues are not discussed in this memo.
        10.  Authors' Addresses
             Jeffrey D. Case
             SNMP Research, Inc.
             3001 Kimberlin Heights Rd.
             Knoxville, TN  37920-9716
             US
             Phone: +1 615 573 1434
             Email: case@snmp.com
             Keith McCloghrie
             Hughes LAN Systems
             1225 Charleston Road
             Mountain View, CA  94043
             US
             Phone: +1 415 966 7934
             Email: kzm@hls.com
             Marshall T. Rose
             Dover Beach Consulting, Inc.
             420 Whisman Court
             Mountain View, CA  94043-2186
             US
             Phone: +1 415 968 1052
             Email: mrose@dbc.mtview.ca.us
             Steven Waldbusser
             Carnegie Mellon University
             4910 Forbes Ave
             Pittsburgh, PA  15213
             US
             Phone: +1 412 268 6628
             Email: waldbusser@cmu.edu
        Case, McCloghrie, Rose & Waldbusser                  [Page 32]
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