rfc1904.txt

著名的RFC文档,其中有一些文档是已经翻译成中文的的.


RFC 1904           Conformance Statements for SNMPv2        January 1996


   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.

5.1.  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   "deprecated" value indicates that the specification is obsolete, but
   that an implementor may wish to support that object to foster
   interoperability with older implementations.

5.2.  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.

5.3.  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.

5.4.  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 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.

5.4.1.  Mapping of the MANDATORY-GROUPS clause

   The MANDATORY-GROUPS clause, which need not be present, names the one
   or more object or notification 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 and notification
   within each conformance group listed.  That is, if a SNMPv2 entity
   returns a noSuchObject exception in response to a management protocol
   get operation [4] for any object within any mandatory conformance
   group for every MIB view, or if the SNMPv2 entity cannot generate
   each notification listed in any conformance group under the



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   appropriate circumstances, then that SNMPv2 entity is not a
   conformant implementation of the MIB module.

5.4.2.  Mapping of the GROUP clause

   The GROUP clause, which need not be present, is repeatedly used to
   name each object and notification group which is conditionally
   mandatory or unconditionally optional for compliance to the MIB
   module.  A 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 group which is named in neither a MANDATORY-GROUPS clause nor a
   GROUP clause, is unconditionally optional for compliance to the MIB
   module.

5.4.3.  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 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.

   By definition, each object specified in an OBJECT clause follows a
   MODULE clause which names the information module in which that object
   is defined.  Therefore, the use of an IMPORTS statement, to specify
   from where such objects are imported, is redundant and is not
   required in an information module.

5.4.3.1.  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 9 of [2] for more information on refined syntax.








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5.4.3.2.  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 9 of [2] for more information on refined syntax.

5.4.3.3.  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 include: conceptual tables
   and rows, auxiliary objects, and objects with the syntax of
   Counter32, Counter64 (and possibly, certain types of textual
   conventions).  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.

5.4.4.  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.

5.5.  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.







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5.6.  Usage Example

   The compliance statement contained in the (hypothetical) XYZv2-MIB
   might be:

xyzMIBCompliance MODULE-COMPLIANCE
    STATUS  current
    DESCRIPTION
            "The compliance statement for XYZv2 entities which implement
            the XYZv2 MIB."
    MODULE  -- compliance to the containing MIB module
        MANDATORY-GROUPS { xyzSystemGroup,
                           xyzStatsGroup, xyzTrapGroup,
                           xyzSetGroup,
                           xyzBasicNotificationsGroup }

        GROUP   xyzV1Group
        DESCRIPTION
            "The xyzV1 group is mandatory only for those
             XYZv2 entities which also implement XYZv1."
::= { xyzMIBCompliances 1 }

   According to this invocation, to claim alignment with the compliance
   statement named

     { xyzMIBCompliances 1 }

   a system must implement the XYZv2-MIB's xyzSystemGroup,
   xyzStatsGroup, xyzTrapGroup, and xyzSetGroup object conformance
   groups, as well as the xyzBasicNotificationsGroup notifications
   group.  Furthermore, if the XYZv2 entity also implements XYZv1, then
   it must also support the XYZv1Group group, if compliance is to be
   claimed.

6.  Mapping of the AGENT-CAPABILITIES macro

   The AGENT-CAPABILITIES macro is used to convey a set of 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



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   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 an instance
   of sysORID [3].  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 from the agent the values of all instances of sysORID [3].
   Based on this, it consults the database to locate each entry matching
   one of the retrieved values of sysORID.  Using the located entries,
   the management application can now optimize its behavior accordingly.

   Note that the AGENT-CAPABILITIES macro specifies refinements or
   variations with respect to OBJECT-TYPE and NOTIFICATION-TYPE macros
   in MIB modules, NOT with respect to MODULE-COMPLIANCE macros in
   compliance statements.

6.1.  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 set of
   capabilities.

6.2.  Mapping of the STATUS clause

   The STATUS clause, which must be present, indicates whether this
   definition is current ("current") or historic ("obsolete").

6.3.  Mapping of the DESCRIPTION clause

   The DESCRIPTION clause, which must be present, contains a textual
   description of this set of capabilities.

6.4.  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.





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6.5.  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.

6.5.1.  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
   SUPPORTS clause, which the agent claims to implement.

6.5.2.  Mapping of the VARIATION clause

   The VARIATION clause, which need not be present, is repeatedly used
   to name each object or notification which the agent implements in
   some variant or refined fashion with respect to the correspondent
   invocation of the OBJECT-TYPE or NOTIFICATION-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.

   By definition, each object specified in a VARIATION clause follows a
   SUPPORTS clause which names the information module in which that
   object is defined.  Therefore, the use of an IMPORTS statement, to
   specify from where such objects are imported, is redundant and is not
   required in an information module.

6.5.2.1.  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 9 of [2] for more information on refined syntax.

6.5.2.2.  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 9 of [2] for more information on refined syntax.



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