    Network Working Group                                         F. Strauss
    Request for Comments: 3781                               TU Braunschweig
    Category: Experimental                                  J. Schoenwaelder
                                             International University Bremen
                                                                    May 2004

          Next Generation Structure of Management Information (SMIng)
           Mappings to the Simple Network Management Protocol (SNMP)

    Status of this Memo

       This memo defines an Experimental Protocol for the Internet
       community.  It does not specify an Internet standard of any kind.
       Discussion and suggestions for improvement are requested.
       Distribution of this memo is unlimited.

    Copyright Notice

       Copyright (C) The Internet Society (2004).  All Rights Reserved.

    Abstract

       SMIng (Structure of Management Information, Next Generation)
       (RFC3780), is a protocol-independent data definition language for
       management information.  This memo defines an SMIng language
       extension that specifies the mapping of SMIng definitions of
       identities, classes, and their attributes and events to dedicated
       definitions of nodes, scalar objects, tables and columnar objects,
       and notifications, for application to the SNMP management framework.

    Table of Contents

       1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
       2.  SNMP Based Internet Management . . . . . . . . . . . . . . . .  3
           2.1.   Kinds of Nodes. . . . . . . . . . . . . . . . . . . . .  4
           2.2.   Scalar and Columnar Object Instances. . . . . . . . . .  5
           2.3.   Object Identifier Hierarchy . . . . . . . . . . . . . .  7
       3.  SMIng Data Type Mappings . . . . . . . . . . . . . . . . . . .  8
           3.1.   ASN.1 Definitions . . . . . . . . . . . . . . . . . . .  9
       4.  The snmp Extension Statement . . . . . . . . . . . . . . . . . 10
           4.1.   The oid Statement . . . . . . . . . . . . . . . . . . . 10
           4.2.   The node Statement. . . . . . . . . . . . . . . . . . . 10
                  4.2.1. The node's oid Statement . . . . . . . . . . . . 10
                  4.2.2. The node's represents Statement. . . . . . . . . 10
                  4.2.3. The node's status Statement. . . . . . . . . . . 11
                  4.2.4. The node's description Statement . . . . . . . . 11
                  4.2.5. The node's reference Statement . . . . . . . . . 11

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                  4.2.6. Usage Examples . . . . . . . . . . . . . . . . . 11
           4.3.   The scalars Statement . . . . . . . . . . . . . . . . . 11
                  4.3.1. The scalars' oid Statement . . . . . . . . . . . 12
                  4.3.2. The scalars' object Statement  . . . . . . . . . 12
                  4.3.3. The scalars' status Statement  . . . . . . . . . 13
                  4.3.4. The scalars' description Statement . . . . . . . 14
                  4.3.5. The scalars' reference Statement . . . . . . . . 14
                  4.3.6. Usage Example. . . . . . . . . . . . . . . . . . 14
           4.4.   The table Statement . . . . . . . . . . . . . . . . . . 14
                  4.4.1. The table's oid Statement. . . . . . . . . . . . 15
                  4.4.2. Table Indexing Statements. . . . . . . . . . . . 15
                  4.4.3. The table's create Statement . . . . . . . . . . 17
                  4.4.4. The table's object Statement . . . . . . . . . . 17
                  4.4.5. The table's status Statement . . . . . . . . . . 19
                  4.4.6. The table's description Statement  . . . . . . . 19
                  4.4.7. The table's reference Statement  . . . . . . . . 19
                  4.4.8. Usage Example  . . . . . . . . . . . . . . . . . 19
           4.5.   The notification Statement  . . . . . . . . . . . . . . 20
                  4.5.1. The notification's oid Statement . . . . . . . . 20
                  4.5.2. The notification's signals Statement . . . . . . 20
                  4.5.3. The notification's status Statement  . . . . . . 20
                  4.5.4. The notification's description Statement . . . . 21
                  4.5.5. The notification's reference Statement . . . . . 21
                  4.5.6. Usage Example. . . . . . . . . . . . . . . . . . 21
           4.6.   The group Statement . . . . . . . . . . . . . . . . . . 21
                  4.6.1. The group's oid Statement  . . . . . . . . . . . 22
                  4.6.2. The group's members Statement  . . . . . . . . . 22
                  4.6.3. The group's status Statement . . . . . . . . . . 22
                  4.6.4. The group's description Statement  . . . . . . . 22
                  4.6.5. The group's reference Statement  . . . . . . . . 22
                  4.6.6. Usage Example  . . . . . . . . . . . . . . . . . 22
           4.7.   The compliance Statement. . . . . . . . . . . . . . . . 23
                  4.7.1. The compliance's oid Statement . . . . . . . . . 23
                  4.7.2. The compliance's status Statement  . . . . . . . 23
                  4.7.3. The compliance's description Statement . . . . . 23
                  4.7.4. The compliance's reference Statement . . . . . . 23
                  4.7.5. The compliance's mandatory Statement . . . . . . 24
                  4.7.6. The compliance's optional Statement. . . . . . . 24
                  4.7.7. The compliance's refine Statement  . . . . . . . 24
                  4.7.8. Usage Example  . . . . . . . . . . . . . . . . . 26
       5.  NMRG-SMING-SNMP-EXT  . . . . . . . . . . . . . . . . . . . . . 26
       6.  NMRG-SMING-SNMP  . . . . . . . . . . . . . . . . . . . . . . . 33
       7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 46
       8.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 46

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       9.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 47
           9.1.   Normative References. . . . . . . . . . . . . . . . . . 47
           9.2.   Informative References. . . . . . . . . . . . . . . . . 47
       Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 48
       Full Copyright Statement . . . . . . . . . . . . . . . . . . . . . 49

    1.  Introduction

       SMIng (Structure of Management Information, Next Generation)
       [RFC3780] is a protocol-independent data definition language for
       management information.  This memo defines an SMIng language
       extension that specifies the mapping of SMIng definitions of
       identities, classes, and their attributes and events to dedicated
       definitions of nodes, scalar objects, tables and columnar objects,
       and notifications for application in the SNMP management framework.
       Section 2 introduces basics of the SNMP management framework.
       Section 3 defines how SMIng data types are mapped to the data types
       supported by the SNMP protocol.  It introduces some new ASN.1 [ASN1]
       definitions which are used to represent new SMIng base types such as
       floats in the SNMP protocol.

       Section 4 describes the semantics of the SNMP mapping extensions for
       SMIng.  The formal SMIng specification of the extension is provided
       in Section 5.

       Section 6 contains an SMIng module which defines derived types (such
       as RowStatus) that are specific to the SNMP mapping.

       The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
       "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
       document are to be interpreted as described in [RFC2119].

    2.  SNMP-Based Internet Management

       The SNMP network management framework [RFC3410] is based on the
       concept of "managed objects".  Managed objects represent real or
       synthesized variables of systems that are to be managed.  Note that
       in spite of these terms this model is not object-oriented.  For
       naming purposes, the managed objects are organized hierarchically in
       an "object identifier tree", where only leaf nodes may represent
       objects.

       Nodes in the object identifier tree may also identify conceptual
       tables, rows of conceptual tables, notifications, groups of objects
       and/or notifications, compliance statements, modules or other
       information.  Each node is identified by an unique "object
       identifier" value which is a sequence of non-negative numbers, named
       "sub-identifiers", where the left-most sub-identifier refers to the

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       node next to the root of the tree and the right-most sub-identifier
       refers to the node that is identified by the complete object
       identifier value.  Each sub-identifier has a value between 0 and
       2^32-1 (4294967295).

       The SMIng extensions described in this document are used to map SMIng
       data definitions to SNMP compliant managed objects.  This mapping is
       designed to be readable to computer programs, named MIB compilers, as
       well as to human readers.

    2.1.  Kinds of Nodes

       Each node in the object identifier tree is of a certain kind and may
       represent management information or not:

       o  Simple nodes, that do not represent management information, but
          may be used for grouping nodes in a subtree.  Those nodes are
          defined by the `node' statement.  This statement can also be used
          to map an SMIng `identity' to a node.

       o  Nodes representing the identity of a module to allow references to
          a module in other objects of type `ObjectIdentifier'.  Those nodes
          are defined by the `snmp' statement,

       o  Scalar objects, which have exactly one object instance and no
          child nodes.  See Section 2.2 for scalar objects' instances.  A
          set of scalar objects is mapped from one or more SMIng classes
          using the `scalars' statement.  The statement block of the
          `scalars' statement contains one `implements' statement for each
          class.  The associated statement blocks in turn contain `object'
          statements that specify the mapping of attributes to scalar
          objects.  Scalar objects MUST not have any child node.

       o  Tables, which represent the root node of a collection of
          information structured in table rows.  Table nodes are defined by
          the `table' statement.  A table object identifier SHOULD not have
          any other child node than the implicitly defined row node (see
          below).

       o  Rows, which belong to a table (that is, row's object identifier
          consists of the table's full object identifier plus a single `1'
          sub-identifier) and represent a sequence of one or more columnar
          objects.  A row node is implicitly defined for each table node.

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       o  Columnar objects, which belong to a row (that is, the columnar
          objects' object identifier consists of the row's full object
          identifier plus a single column-identifying sub-identifier) and
          have zero or more object instances and no child nodes.  They are
          defined as follows: The classes that are implemented by a `table'
          statement are identified by `implements' statements.  The
          statement block of each `implements' statement contains `object'
          statements that specify the mapping of attributes to columnar
          objects of this table.  Columnar objects MUST not have any child
          node.

       o  Notifications, which represent information that is sent by agents
          within unsolicited transmissions.  The `notification' statement is
          used to map an SMIng event to a notification.  A notification's
          object identifier SHOULD not have any child node.

       o  Groups of objects and notifications, which may be used for
          compliance statements.  They are defined using the `group'
          statement.

       o  Compliance statements which define requirements for MIB module
          implementations.  They are defined using the `compliance'
          statement.

    2.2.  Scalar and Columnar Object Instances

       Instances of managed objects are identified by appending an
       instance-identifier to the object's object identifier.  Scalar
       objects and columnar objects use different ways to construct the
       instance-identifier.

       Scalar objects have exactly one object instance.  It is identified by
       appending a single `0' sub-identifier to the object identifier of the
       scalar object.

       Within tables, different instances of the same columnar object are
       identified by appending a sequence of one or more sub-identifiers to
       the object identifier of the columnar object which consists of the
       values of object instances that unambiguously distinguish a table
       row.  These indexing objects can be columnar objects of the same
       and/or another table, but MUST NOT be scalar objects.  Multiple
       applications of the same object in a single table indexing
       specification are strongly discouraged.

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       The base types of the indexing objects indicate how to form the
       instance-identifier:

       o  integer-valued or enumeration-valued: a single sub-identifier
          taking the integer value (this works only for non-negative
          integers and integers of a size of up to 32 bits),

       o  string-valued, fixed-length strings (or variable-length with
          compact encoding): `n' sub-identifiers, where `n' is the length of
          the string (each octet of the string is encoded in a separate
          sub-identifier),

       o  string-valued, variable-length strings or bits-valued: `n+1' sub-
          identifiers, where `n' is the length of the string or bits
          encoding (the first sub-identifier is `n' itself, following this,
          each octet of the string or bits is encoded in a separate sub-
          identifier),

       o  object identifier-valued (with compact encoding): `n' sub-
          identifiers, where `n' is the number of sub-identifiers in the
          value (each sub-identifier of the value is copied into a separate
          sub-identifier),

       o  object identifier-valued: `n+1' sub-identifiers, where `n' is the
          number of sub-identifiers in the value (the first sub-identifier
          is `n' itself, following this, each sub-identifier in the value is
          copied),

       Note that compact encoding can only be applied to an object having a
       variable-length syntax (e.g., variable-length strings, bits objects
       or object identifier-valued objects).  Further, compact encoding can
       only be associated with the last object in a list of indexing
       objects.  Finally, compact encoding MUST NOT be used on a variable-
       length string object if that string might have a value of zero-
       length.

       Instances identified by use of integer-valued or enumeration-valued
       objects are RECOMMENDED to be numbered starting from one (i.e., not
       from zero).  Integer objects that allow negative values, Unsigned64
       objects, Integer64 objects and floating point objects MUST NOT be
       used for table indexing.

       Objects which are both specified for indexing in a row and also
       columnar objects of the same row are termed auxiliary objects.
       Auxiliary objects SHOULD be non-accessible, except in the following
       circumstances:

       o  within a module originally written to conform to SMIv1, or

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       o  a row must contain at least one columnar object which is not an
          auxiliary object.  In the event that all of a row's columnar
          objects are also specified to be indexing objects then one of them
          MUST be accessible.

    2.3.  Object Identifier Hierarchy

       The layers of the object identifier tree near the root are well
       defined and organized by standardization bodies.  The first level
       next to the root has three nodes:

          0: ccitt

          1: iso

          2: joint-iso-ccitt

       Note that the renaming of the Commite Consultatif International de
       Telegraphique et Telephonique (CCITT) to International
       Telecommunications Union (ITU) had no consequence on the names used
       in the object identifier tree.

       The root of the subtree administered by the Internet Assigned Numbers
       Authority (IANA) for the Internet is `1.3.6.1' which is assigned with
       the identifier `internet'.  That is, the Internet subtree of object
       identifiers starts with the prefix `1.3.6.1.'.

       Several branches underneath this subtree are used for network
       management:

       The `mgmt' (internet.2) subtree is used to identify "standard"
       definitions.  An information module produced by an IETF working group
       becomes a "standard" information module when the document is first
       approved by the IESG and enters the Internet standards track.

       The `experimental' (internet.3) subtree is used to identify
       experimental definitions being designed by working groups of the IETF
       or IRTF.  If an information module produced by a working group
       becomes a "standard" module, then at the very beginning of its entry
       onto the Internet standards track, the definitions are moved under
       the mgmt subtree.

       The `private' (internet.4) subtree is used to identify definitions
       defined unilaterally.  The `enterprises' (private.1) subtree beneath
       private is used, among other things, to permit providers of
       networking subsystems to register information modules of their
       products.

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       These and some other nodes are defined in the SMIng module NMRG-
       SMING-SNMP-EXT (Section 5).

    3.  SMIng Data Type Mappings

       SMIng [RFC3780] supports the following set of base types:
       OctetString, Pointer, Integer32, Integer64, Unsigned32, Unsigned64,
       Float32, Float64, Float128, Enumeration, Bits, and ObjectIdentifier.

       The SMIng core module NMRG-SMING ([RFC3780], Appendix A) defines
       additional derived types, among them Counter32 (derived from
       Unsigned32), Counter64 (derived from Unsigned64), TimeTicks32 and
       TimeTicks64 (derived from Unsigned32 and Unsigned64), IpAddress
       (derived from OctetString), and Opaque (derived from OctetString).

       The version 2 of the protocol operations for SNMP document [RFC3416]
       defines the following 9 data types which are distinguished by the
       protocol: INTEGER, OCTET STRING, OBJECT IDENTIFIER, IpAddress,
       Counter32, TimeTicks, Opaque, Counter64, and Unsigned32.

       The SMIng base types and their derived types are mapped to SNMP data
       types according to the following table:

             SMIng Data Type    SNMP Data Type         Comment
             ---------------    -------------------    -------
             OctetString        OCTET STRING           (1)
             Pointer            OBJECT IDENTIFIER
             Integer32          INTEGER
             Integer64          Opaque (Integer64)     (2)
             Unsigned32         Unsigned32             (3)
             Unsigned64         Opaque (Unsigned64)    (2) (4)
             Float32            Opaque (Float32)       (2)
             Float64            Opaque (Float64)       (2)
             Float128           Opaque (Float128)      (2)
             Enumeration        INTEGER
             Bits               OCTET STRING
             ObjectIdentifier   OBJECT IDENTIFIER

             Counter32          Counter32
             Counter64          Counter64
             TimeTicks32        TimeTicks
             TimeTicks64        Opaque (Unsigned64)    (2)
             IpAddress          IpAddress
             Opaque             Opaque

          (1) This mapping includes all types derived from the OctetString
              type except those types derived from the IpAddress and Opaque
              SMIng types defined in the module NMRG-SMING.

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          (2) This type is encoded according to the ASN.1 type with the same
              name defined in Section 3.1.  The resulting BER encoded value
              is then wrapped in an Opaque value.

          (3) This mapping includes all types derived from the Unsigned32
              type except those types derived from the Counter32 and
              TimeTicks32 SMIng types defined in the module NMRG-SMING.

          (4) This mapping includes all types derived from the Unsigned64
              type except those types derived from the Counter64 SMIng type
              defined in the module NMRG-SMING.

    3.1.  ASN.1 Definitions

       The ASN.1 [ASN1] type definitions below introduce data types which
       are used to map the new SMIng base types into the set of ASN.1 types
       supported by the second version of SNMP protocol operations
       [RFC3416].

       NMRG-SMING-SNMP-MAPPING DEFINITIONS ::= BEGIN

       Integer64 ::=
           [APPLICATION 10]
               IMPLICIT INTEGER (-9223372036854775808..9223372036854775807)

       Unsigned64
           [APPLICATION 11]
               IMPLICIT INTEGER (0..18446744073709551615)

       Float32
           [APPLICATION 12]
               IMPLICIT OCTET STRING (SIZE (4))

       Float64
           [APPLICATION 13]
               IMPLICIT OCTET STRING (SIZE (8))

       Float128
           [APPLICATION 14]
               IMPLICIT OCTET STRING (SIZE (16))

       END

       The definitions of Integer64 and Unsigned64 are consistent with the
       same definitions in the SPPI [RFC3159].  The floating point types
       Float32, Float64 and Float128 support single, double and quadruple

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       IEEE floating point values.  The encoding of the values follows the
       "IEEE Standard for Binary Floating-Point Arithmetic" as defined in
       ANSI/IEEE Standard 754-1985 [IEEE754].

    4.  The snmp Extension Statement

       The `snmp' statement is the main statement of the SNMP mapping
       specification.  It gets one or two arguments: an optional lower-case
       identifier that specifies a node that represents the module's
       identity, and a mandatory statement block that contains all details
       of the SNMP mapping.  All information of an SNMP mapping are mapped
       to an SNMP conformant module of the same name as the containing SMIng
       module.  A single SMIng module must not contain more than one `snmp'
       statement.

    4.1.  The oid Statement

       The snmp's `oid' statement, which must be present, if the snmp
       statement contains a module identifier and must be absent otherwise,
       gets one argument which specifies the object identifier value that is
       assigned to this module's identity node.

    4.2.  The node Statement

       The `node' statement is used to name and describe a node in the
       object identifier tree, without associating any class or attribute
       information with this node.  This may be useful to group definitions
       in a subtree of related management information, or to uniquely define
       an SMIng `identity' to be referenced in attributes of type Pointer.
       The `node' statement gets two arguments: a lower-case node identifier
       and a statement block that holds detailed node information in an
       obligatory order.

       See the `nodeStatement' rule of the grammar (Section 5) for the
       formal syntax of the `node' statement.

    4.2.1.  The node's oid Statement

       The node's `oid' statement, which must be present, gets one argument
       which specifies the object identifier value that is assigned to this
       node.

    4.2.2.  The node's represents Statement

       The node's `represents' statement, which need not be present, makes
       this node represent an SMIng identity, so that objects of type
       Pointer can reference that identity.  The statement gets one argument
       which specifies the identity name.

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    4.2.3 The node's status Statement

       The node's `status' statement, which must be present, gets one
       argument which is used to specify whether this node definition is
       current or historic.  The value `current' means that the definition
       is current and valid.  The value `obsolete' means the definition is
       obsolete and should not be implemented and/or can be removed if
       previously implemented.  While the value `deprecated' also indicates
       an obsolete definition, it permits new/continued implementation in
       order to foster interoperability with older/existing implementations.

    4.2.4.  The node's description Statement

       The node's `description' statement, which need not be present, gets
       one argument which is used to specify a high-level textual
       description of this node.

       It is RECOMMENDED to include all semantics and purposes of this node.

    4.2.5.  The node's reference Statement

       The node's `reference' statement, which need not be present, gets one
       argument which is used to specify a textual cross-reference to some
       other document, either another module which defines related
       definitions, or some other document which provides additional
       information relevant to this node.

    4.2.6.  Usage Examples

       node iso                            { oid 1;     status current; };
       node   org                          { oid iso.3; status current; };
       node     dod                        { oid org.6; status current; };
       node       internet                 { oid dod.1; status current; };

       node   zeroDotZero {
           oid         0.0;
           represents  NMRG-SMING::null;
           status      current;
           description "A null value used for pointers.";
       };

    4.3.  The scalars Statement

       The `scalars' statement is used to define the mapping of one or more
       classes to a group of SNMP scalar managed objects organized under a
       common parent node.  The `scalars' statement gets two arguments: a

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       lower-case scalar group identifier and a statement block that holds
       detailed mapping information of this scalar group in an obligatory
       order.

       See the `scalarsStatement' rule of the grammar (Section 5) for the
       formal syntax of the `scalars' statement.

    4.3.1.  The scalars' oid Statement

       The scalars' `oid' statement, which must be present, gets one
       argument which specifies the object identifier value that is assigned
       to the common parent node of this scalar group.

    4.3.2.  The scalars' object Statement

       The scalars' `object' statement, which must be present at least once,
       makes this scalar group contain a given scalar object.  It gets two
       arguments: the name of the scalar object to be defined and a
       statement block that holds additional detailed information in an
       obligatory order.

    4.3.2.1.  The object's implements Statement

       The `implements' statement, which must be present, is used to specify
       a single leaf attribute of a class that is implemented by this scalar
       object.  The type of this attribute must be a simple type, i.e., not
       a class.

    4.3.2.2.  The object's subid Statement

       The `subid' statement, which need not be present, is used to specify
       the sub-identifier that identifies the scalar object within this
       scalar group, i.e., the object identifier of the scalar object is the
       concatenation of the values of this scalar group's oid statement and
       of this subid statement.

       If this statement is omitted, the sub-identifier is the one of the
       previous object statement within this scalar group plus 1.  If the
       containing object statement is the first one within the containing
       scalar group and the subid statement is omitted, the sub-identifier
       is 1.

    4.3.2.3.  The object's status Statement

       The object's `status' statement, which need not be present, gets one
       argument which is used to specify whether this scalar object
       definition is current or historic.  The value `current' means that

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       the definition is current and valid.  The value `obsolete' means the
       definition is obsolete and should not be implemented and/or can be
       removed if previously implemented.  While the value `deprecated' also
       indicates an obsolete definition, it permits new/continued
       implementation in order to foster interoperability with
       older/existing implementations.

       Scalar objects SHOULD NOT be defined as `current' if the implemented
       attribute definition is `deprecated' or `obsolete'.  Similarly, they
       SHOULD NOT be defined as `deprecated' if the implemented attribute is
       `obsolete'.  Nevertheless, subsequent revisions of used class
       definitions cannot be avoided, but SHOULD be taken into account in
       subsequent revisions of the local module.

       Note that it is RECOMMENDED to omit the status statement which means
       that the status is inherited from the containing scalars statement.
       However, if the status of a scalar object varies from the containing
       scalar group, it has to be expressed explicitly, e.g., if the
       implemented attribute has been deprecated or obsoleted.

    4.3.2.4.  The object's description Statement

       The object's `description' statement, which need not be present, gets
       one argument which is used to specify a high-level textual
       description of this scalar object.

       Note that in contrast to other definitions this description statement
       is not mandatory and it is RECOMMENDED to omit it, if the object is
       fully described by the description of the implemented attribute.

    4.3.2.5.  The object's reference Statement

       The object's `reference' statement, which need not be present, gets
       one argument which is used to specify a textual cross-reference to
       some other document, either another module which defines related
       definitions, or some other document which provides additional
       information relevant to this scalar object.

       It is RECOMMENDED to omit this statement, if the object's references
       are fully described by the implemented attribute.

    4.3.3.  The scalars' status Statement

       The scalars' `status' statement, which must be present, gets one
       argument which is used to specify whether this scalar group
       definition is current or historic.  The value `current' means that
       the definition is current and valid.  The value `obsolete' means the
       definition is obsolete and should not be implemented and/or can be

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       removed if previously implemented.  While the value `deprecated' also
       indicates an obsolete definition, it permits new/continued
       implementation in order to foster interoperability with
       older/existing implementations.

    4.3.4.  The scalars' description Statement

       The scalars' `description' statement, which must be present, gets one
       argument which is used to specify a high-level textual description of
       this scalar group.

       It is RECOMMENDED to include all semantic definitions necessary for
       the implementation of this scalar group.

    4.3.5.  The scalars' reference Statement

       The scalars' `reference' statement, which need not be present, gets
       one argument which is used to specify a textual cross-reference to
       some other document, either another module which defines related
       definitions, or some other document which provides additional
       information relevant to this scalars statement.

    4.3.6.  Usage Example

       scalars ip {
         oid             mib-2.4;
         object ipForwarding { implements Ip.forwarding; };
         object ipDefaultTTL { implements Ip.defaultTTL; };
         // ...
         status          current;
         description
                 "This scalar group implements the Ip class.";
       };

    4.4.  The table Statement

       The `table' statement is used to define the mapping of one or more
       classes to a single SNMP table of columnar managed objects.  The
       `table' statement gets two arguments: a lower-case table identifier
       and a statement block that holds detailed mapping information of this
       table in an obligatory order.

       See the `tableStatement' rule of the grammar (Section 5) for the
       formal syntax of the `table' statement.

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    4.4.1.  The table's oid Statement

       The table's `oid' statement, which must be present, gets one argument
       which specifies the object identifier value that is assigned to this
       table's node.

    4.4.2.  Table Indexing Statements

       SNMP table mappings offers five methods to supply table indexing
       information: ordinary tables, table augmentations, sparse table
       augmentations, table expansions, and reordered tables use different
       statements to denote their indexing information.  Each table
       definition must contain exactly one of the following indexing
       statements.

    4.4.2.1.  The table's index Statement for Table Indexing

       The table's `index' statement, which is used to supply table indexing
       information of base tables, gets one argument that specifies a
       comma-separated list of objects, that are used for table indexing,
       enclosed in parenthesis.

       The elements of the `unique' statement of the implemented class(es)
       and their order should be regarded as a hint for the index elements
       of the table.

       In case of modules that should be compatible on the SNMP protocol
       level to SMIv2 versions of the module, an optional `implied' keyword
       may be added in front of the list to indicate a compact encoding of
       the last object in the list.  See Section 2.2 for details.

    4.4.2.2.  The table's augments Statement for Table Indexing

       The table's `augments' statement, which is used to supply table
       indexing information of tables that augment a base table, gets one
       argument that specifies the identifier of the table to be augmented.
       Note that a table augmentation cannot itself be augmented.  Anyhow, a
       base table may be augmented by multiple table augmentations.

       A table augmentation makes instances of subordinate columnar objects
       identified according to the index specification of the base table
       corresponding to the table named in the `augments' statement.
       Further, instances of subordinate columnar objects of a table
       augmentation exist according to the same semantics as instances of
       subordinate columnar objects of the base table being augmented.  As
       such, note that creation of a base table row implies the

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       correspondent creation of any table row augmentations.  Table
       augmentations MUST NOT be used in table row creation and deletion
       operations.

    4.4.2.3.  The table's extends Statement for Table Indexing

       The table's `extends' statement, which is used to supply table
       indexing information of tables that sparsely augment a base table,
       gets one argument that specifies the identifier of the table to be
       sparsely augmented.  Note that a sparse table augmentation cannot
       itself be augmented.  Anyhow, a base table may be augmented by
       multiple table augmentations, sparsely or not.

       A sparse table augmentation makes instances of subordinate columnar
       objects identified, if present, according to the index specification
       of the base table corresponding to the table named in the `extends'
       statement.  Further, instances of subordinate columnar objects of a
       sparse table augmentation exist according to the semantics as
       instances of subordinate columnar objects of the base table and the
       (non-formal) rules that confine the sparse relationship.  As such,
       note that creation of a sparse table row augmentation may be implied
       by the creation of a base table row as well as done by an explicit
       creation.  However, if a base table row gets deleted, any dependent
       sparse table row augmentations get also deleted implicitly.

    4.4.2.4.  The table's reorders Statement for Table Indexing

       The table's `reorders' statement is used to supply table indexing
       information of tables, that contain exactly the same index objects of
       a base table but in a different order.  It gets at least two
       arguments.  The first one specifies the identifier of the base table.
       The second one specifies a comma-separated list of exactly those
       object identifiers of the base table's `index' statement, but in the
       order to be used in this table.  Note that a reordered table cannot
       itself be reordered.  Anyhow, a base table may be used for multiple
       reordered tables.

       Under some circumstances, an optional `implied' keyword may be added
       in front of the list to indicate a compact encoding of the last
       object in the list.  See Section 2.2 for details.

       Instances of subordinate columnar objects of a reordered table exist
       according to the same semantics as instances of subordinate columnar
       objects of the base table.  As such, note that creation of a base
       table row implies the correspondent creation of any related reordered
       table row.  Reordered tables MUST NOT be used in table row creation
       and deletion operations.

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    4.4.2.5.  The table's expands Statement for Table Indexing

       The table's `expands' statement is used to supply table indexing
       information of table expansions.  Table expansions use exactly the
       same index objects of another table together with additional indexing
       objects.  Thus, the `expands' statement gets at least two arguments.
       The first one specifies the identifier of the base table.  The second
       one specifies a comma-separated list of the additional object
       identifiers used for indexing.  Note that an expanded table may
       itself be expanded, and base tables may be used for multiple table
       expansions.

       Under some circumstances, an optional `implied' keyword may be added
       in front of the list to indicate a compact encoding of the last
       object in the list.  See Section 2.2 for details.

    4.4.3.  The table's create Statement

       The table's `create' statement, which need not be present, gets no
       argument.  If the `create' statement is present, table row creation
       (and deletion) is possible.

    4.4.4.  The table's object Statement

       The table's `object' statement, which must be present at least once,
       makes this table contain a given columnar object.  It gets two
       arguments: the name of the columnar object to be defined and a
       statement block that holds additional detailed information in an
       obligatory order.

    4.4.4.1.  The object's implements Statement

       The `implements' statement, which must be present, is used to specify
       a single leaf attribute of a class that is implemented by this
       columnar object.  The type of this attribute must be a simple type,
       i.e., not a class.

    4.4.4.2.  The object's subid Statement

       The `subid' statement, which need not be present, is used to specify
       the sub-identifier that identifies the columnar object within this
       table, i.e., the object identifier of the columnar object is the
       concatenation of the values of this table's oid statement and of this
       subid statement.

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       If this statement is omitted, the sub-identifier is the one of the
       previous object statement within this table plus 1.  If the
       containing object statement is the first one within the containing
       table and the subid statement is omitted, the sub-identifier is 1.

    4.4.4.3.  The object's status Statement

       The object's `status' statement, which need not be present, gets one
       argument which is used to specify whether this columnar object
       definition is current or historic.  The value `current' means that
       the definition is current and valid.  The value `obsolete' means the
       definition is obsolete and should not be implemented and/or can be
       removed if previously implemented.  While the value `deprecated' also
       indicates an obsolete definition, it permits new/continued
       implementation in order to foster interoperability with
       older/existing implementations.

       Columnar objects SHOULD NOT be defined as `current' if the
       implemented attribute definition is `deprecated' or `obsolete'.
       Similarly, they SHOULD NOT be defined as `deprecated' if the
       implemented attribute is `obsolete'.  Nevertheless, subsequent
       revisions of used class definitions cannot be avoided, but SHOULD be
       taken into account in subsequent revisions of the local module.

       Note that it is RECOMMENDED to omit the status statement which means
       that the status is inherited from the containing table statement.
       However, if the status of a columnar object varies from the
       containing table, it has to be expressed explicitly, e.g., if the
       implemented attribute has been deprecated or obsoleted.

    4.4.4.4.  The object's description Statement

       The object's `description' statement, which need not be present, gets
       one argument which is used to specify a high-level textual
       description of this columnar object.

       Note that in contrast to other definitions this description statement
       is not mandatory and it is RECOMMENDED to omit it, if the object is
       fully described by the description of the implemented attribute.

    4.4.4.5.  The object's reference Statement

       The object's `reference' statement, which need not be present, gets
       one argument which is used to specify a textual cross-reference to
       some other document, either another module which defines related
       definitions, or some other document which provides additional
       information relevant to this columnar object.

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       It is RECOMMENDED to omit this statement, if the object's references
       are fully described by the implemented attribute.

    4.4.5.  The table's status Statement

       The table's `status' statement, which must be present, gets one
       argument which is used to specify whether this table definition is
       current or historic.  The value `current' means that the definition
       is current and valid.  The value `obsolete' means the definition is
       obsolete and should not be implemented and/or can be removed if
       previously implemented.  While the value `deprecated' also indicates
       an obsolete definition, it permits new/continued implementation in
       order to foster interoperability with older/existing implementations.

    4.4.6.  The table's description Statement

       The table's `description' statement, which must be present, gets one
       argument which is used to specify a high-level textual description of
       this table.

       It is RECOMMENDED to include all semantic definitions necessary for
       the implementation of this table.

    4.4.7.  The table's reference Statement

       The table's `reference' statement, which need not be present, gets
       one argument which is used to specify a textual cross-reference to
       some other document, either another module which defines related
       definitions, or some other document which provides additional
       information relevant to this table statement.

    4.4.8.  Usage Example

       table ifTable {
         oid             interfaces.2;
         index           (ifIndex);
         object ifIndex { implements Interface.index;       };
         object ifDescr { implements Interface.description; };
         // ...
         status          current;
         description
                 "This table implements the Interface class.";
       };

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    4.5.  The notification Statement

       The `notification' statement is used to map events defined within
       classes to SNMP notifications.  The `notification' statement gets two
       arguments: a lower-case notification identifier and a statement block
       that holds detailed notification information in an obligatory order.

       See the `notificationStatement' rule of the grammar (Section 5) for
       the formal syntax of the `notification' statement.

    4.5.1.  The notification's oid Statement

       The notification's `oid' statement, which must be present, gets one
       argument which specifies the object identifier value that is assigned
       to this notification.

    4.5.2.  The notification's signals Statement

       The notification's `signals' statement, which must be present,
       denotes the event that is signaled by this notification.  The
       statement gets two arguments: the event to be signaled (in the
       qualified form `Class.event') and a statement block that holds
       detailed information on the objects transmitted with this
       notification in an obligatory order.

    4.5.2.1.  The signals' object Statement

       The signals' `object' statement, which can be present zero, one or
       multiple times, makes a single instance of a class attribute be
       contained in this notification.  It gets one argument: the specific
       class attribute.  The namespace of attributes not specified by
       qualified names is the namespace of the event's class specified in
       the `signals' statement.

    4.5.3.  The notification's status Statement

       The notification's `status' statement, which must be present, gets
       one argument which is used to specify whether this notification
       definition is current or historic.  The value `current' means that
       the definition is current and valid.  The value `obsolete' means the
       definition is obsolete and should not be implemented and/or can be
       removed if previously implemented.  While the value `deprecated' also
       indicates an obsolete definition, it permits new/continued
       implementation in order to foster interoperability with
       older/existing implementations.

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    4.5.4.  The notification's description Statement

       The notification's `description' statement, which need not be
       present, gets one argument which is used to specify a high-level
       textual description of this notification.

       It is RECOMMENDED to include all semantics and purposes of this
       notification.

    4.5.5.  The notification's reference Statement

       The notification's `reference' statement, which need not be present,
       gets one argument which is used to specify a textual cross-reference
       to some other document, either another module which defines related
       definitions, or some other document which provides additional
       information relevant to this notification statement.

    4.5.6.  Usage Example

       notification linkDown {
           oid         snmpTraps.3;
           signals     Interface.linkDown {
               object      ifIndex;
               object      ifAdminStatus;
               object      ifOperStatus;
           };
           status      current;
           description
                 "This notification signals the linkDown event
                  of the Interface class.";
       };

    4.6.  The group Statement

       The `group' statement is used to define a group of arbitrary nodes in
       the object identifier tree.  It gets two arguments: a lower-case
       group identifier and a statement block that holds detailed group
       information in an obligatory order.

       Note that the primary application of groups are compliance
       statements, although they might be referred in other formal or
       informal documents.

       See the `groupStatement' rule of the grammar (Section 5) for the
       formal syntax of the `group' statement.

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    4.6.1.  The group's oid Statement

       The group's `oid' statement, which must be present, gets one argument
       which specifies the object identifier value that is assigned to this
       group.

    4.6.2.  The group's members Statement

       The group's `members' statement, which must be present, gets one
       argument which specifies the list of nodes by their identifiers to be
       contained in this group.  The list of nodes has to be comma-separated
       and enclosed in parenthesis.

    4.6.3.  The group's status Statement

       The group's `status' statement, which must be present, gets one
       argument which is used to specify whether this group definition is
       current or historic.  The value `current' means that the definition
       is current and valid.  The value `obsolete' means the definition is
       obsolete and the group should no longer be used.  While the value
       `deprecated' also indicates an obsolete definition, it permits
       new/continued use of this group.

    4.6.4.  The group's description Statement

       The group's `description' statement, which must be present, gets one
       argument which is used to specify a high-level textual description of
       this group.  It is RECOMMENDED to include any relation to other
       groups.

    4.6.5.  The group's reference Statement

       The group's `reference' statement, which need not be present, gets
       one argument which is used to specify a textual cross-reference to
       some other document, either another module which defines related
       groups, or some other document which provides additional information
       relevant to this group.

    4.6.6.  Usage Example

       The snmpGroup, originally defined in [RFC3418], may be described as
       follows:

       group snmpGroup {
         oid             snmpMIBGroups.8;
         objects         (snmpInPkts, snmpInBadVersions,
                          snmpInASNParseErrs,
                          snmpSilentDrops, snmpProxyDrops,

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                          snmpEnableAuthenTraps);
         status          current;
         description
                 "A collection of objects providing basic
                  instrumentation and control of an agent.";
       };

    4.7.  The compliance Statement

       The `compliance' statement is used to define a set of conformance
       requirements, named a `compliance statement'.  It gets two arguments:
       a lower-case compliance identifier and a statement block that holds
       detailed compliance information in an obligatory order.

       See the `complianceStatement' rule of the grammar (Section 5) for the
       formal syntax of the `compliance' statement.

    4.7.1.  The compliance's oid Statement

       The compliance's `oid' statement, which must be present, gets one
       argument which specifies the object identifier value that is assigned
       to this compliance statement.

    4.7.2.  The compliance's status Statement

       The compliance's `status' statement, which must be present, gets one
       argument which is used to specify whether this compliance statement
       is current or historic.  The value `current' means that the
       definition is current and valid.  The value `obsolete' means the
       definition is obsolete and no longer specifies a valid definition of
       conformance.  While the value `deprecated' also indicates an obsolete
       definition, it permits new/continued use of the compliance
       specification.

    4.7.3.  The compliance's description Statement

       The compliance's `description' statement, which must be present, gets
       one argument which is used to specify a high-level textual
       description of this compliance statement.

    4.7.4.  The compliance's reference Statement

       The compliance's `reference' statement, which need not be present,
       gets one argument which is used to specify a textual cross-reference
       to some other document, either another module which defines related
       compliance statements, or some other document which provides
       additional information relevant to this compliance statement.

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    4.7.5.  The compliance's mandatory Statement

       The compliance's `mandatory' statement, which need not be present,
       gets one argument which is used to specify a comma-separated list of
       one or more groups (Section 4.6) of objects and/or notifications
       enclosed in parenthesis.  These groups are unconditionally mandatory
       for implementation.

       If an agent claims compliance to a MIB module then it must implement
       each and every object and notification within each group listed in
       the `mandatory' statement(s) of the compliance statement(s) of that
       module.

    4.7.6.  The compliance's optional Statement

       The compliance's `optional' statement, which need not be present, is
       repeatedly used to name each group which is conditionally mandatory
       for compliance to the compliance statement.  It can also be used to
       name unconditionally optional groups.  A group named in an `optional'
       statement MUST be absent from the correspondent `mandatory'
       statement.  The `optional' statement gets two arguments: a lower-case
       group identifier and a statement block that holds detailed compliance
       information on that group.

       Conditionally mandatory groups include those groups which are
       mandatory only if a particular protocol is implemented, or only if
       another group is implemented.  The `description' statement specifies
       the conditions under which the group is conditionally mandatory.

       A group which is named in neither a `mandatory' statement nor an
       `optional' statement, is unconditionally optional for compliance to
       the module.

       See the `optionalStatement' rule of the grammar (Section 5) for the
       formal syntax of the `optional' statement.

    4.7.6.1.  The optional's description Statement

       The optional's `description' statement, which must be present, gets
       one argument which is used to specify a high-level textual
       description of the conditions under which this group is conditionally
       mandatory or unconditionally optional.

    4.7.7.  The compliance's refine Statement

       The compliance's `refine' statement, which need not be present, is
       repeatedly used to specify each object for which compliance has a
       refined requirement with respect to the module definition.  The

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       object must be present in one of the conformance groups named in the
       correspondent `mandatory' or `optional' statements.  The `refine'
       statement gets two arguments: a lower-case identifier of a scalar or
       columnar object and a statement block that holds detailed refinement
       information on that object.

       See the `refineStatement' rule of the grammar (Section 5) for the
       formal syntax of the `refine' statement.

    4.7.7.1. The refine's type Statement

       The refine's `type' statement, which need not be present, gets one
       argument that is used to provide a refined type for the correspondent
       object.  Type restrictions may be applied by appending subtyping
       information according to the rules of the base type.  See [RFC3780]
       for SMIng base types and their type restrictions.  In case of
       enumeration or bitset types the order of named numbers is not
       significant.

       Note that if a `type' and a `writetype' statement are both present
       then this type only applies when instances of the correspondent
       object are read.

    4.7.7.2.  The refine's writetype Statement

       The refine's `writetype' statement, which need not be present, gets
       one argument that is used to provide a refined type for the
       correspondent object, only when instances of that object are written.
       Type restrictions may be applied by appending subtyping information
       according to the rules of the base type.  See [RFC3780] for SMIng
       base types and their type restrictions.  In case of enumeration or
       bitset types the order of named numbers is not significant.

    4.7.7.3.  The refine's access Statement

       The refine's `access' statement, which need not be present, gets one
       argument that is used to specify the minimal level of access that the
       correspondent object must implement in the sense of its original
       `access' statement.  Hence, the refine's `access' statement MUST NOT
       specify a greater level of access than is specified in the
       correspondent object definition.

       An implementation is compliant if the level of access it provides is
       greater or equal to the minimal level in the refine's `access'
       statement and less or equal to the maximal level in the object's
       `access' statement.

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    4.7.7.4.  The refine's description Statement

       The refine's `description' statement, which must be present, gets one
       argument which is used to specify a high-level textual description of
       the refined compliance requirement.

    4.7.8.  Usage Example

       The compliance statement contained in the SNMPv2-MIB [RFC3418],
       converted to SMIng:

          compliance snmpBasicComplianceRev2 {
            oid             snmpMIBCompliances.3;
            status          current;
            description
                    "The compliance statement for SNMP entities which
                     implement this MIB module.";

            mandatory       (snmpGroup, snmpSetGroup, systemGroup,
                             snmpBasicNotificationsGroup);

            optional snmpCommunityGroup {
              description
                    "This group is mandatory for SNMP entities which
                     support community-based authentication.";
            };
            optional snmpWarmStartNotificationGroup {
              description
                    "This group is mandatory for an SNMP entity which
                     supports command responder applications, and is
                     able to reinitialize itself such that its
                     configuration is unaltered.";
            };
          };

    5. NMRG-SMING-SNMP-EXT

       The grammar of the snmp statement (including all its contained
       statements) conforms to the Augmented Backus-Naur Form (ABNF)
       [RFC2234].  It is included in the abnf statement of the snmp SMIng
       extension definition in the NMRG-SMING-SNMP-EXT module below.

       module NMRG-SMING-SNMP-EXT {

          organization    "IRTF Network Management Research Group (NMRG)";

          contact         "IRTF Network Management Research Group (NMRG)
                           http://www.ibr.cs.tu-bs.de/projects/nmrg/

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                           Frank Strauss
                           TU Braunschweig
                           Muehlenpfordtstrasse 23
                           38106 Braunschweig
                           Germany
                           Phone: +49 531 391 3266
                           EMail: strauss@ibr.cs.tu-bs.de

                           Juergen Schoenwaelder
                           International University Bremen
                           P.O. Box 750 561
                           28725 Bremen
                           Germany
                           Phone: +49 421 200 3587
                           EMail: j.schoenwaelder@iu-bremen.de";

          description     "This module defines a SMIng extension to define
                           the mapping of SMIng definitions of class and
                           their attributes and events to SNMP compatible
                           definitions of modules, node, scalars, tables,
                           and notifications, and additional information on
                           module compliances.

                           Copyright (C) The Internet Society (2004).
                           All Rights Reserved.
                           This version of this module is part of
                           RFC 3781, see the RFC itself for full
                           legal notices.";

          revision {
              date        "2003-12-16";
              description "Initial revision, published as RFC 3781.";
          };

          //
          //
          //

          extension snmp {

              status          current;
              description
                 "The snmp statement maps SMIng definitions to SNMP
                  conformant definitions.";
              abnf "
     ;;
     ;; sming-snmp.abnf -- Grammar of SNMP mappings in ABNF
     ;;                    notation (RFC 2234).

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     ;;
     ;; @(#) $Id: sming-snmp.abnf,v 1.14 2003/10/23 19:31:55 strauss Exp $
     ;;
     ;; Copyright (C) The Internet Society (2004). All Rights Reserved.
     ;;

     ;;
     ;; Statement rules.
     ;;

     snmpStatement           = snmpKeyword *1(sep lcIdentifier) optsep
                                   \"{\" stmtsep
                                   *1(oidStatement stmtsep)
                                   *(nodeStatement stmtsep)
                                   *(scalarsStatement stmtsep)
                                   *(tableStatement stmtsep)
                                   *(notificationStatement stmtsep)
                                   *(groupStatement stmtsep)
                                   *(complianceStatement stmtsep)
                                   statusStatement stmtsep
                                   descriptionStatement stmtsep
                                   *1(referenceStatement stmtsep)
                               \"}\" optsep \";\"

     nodeStatement           = nodeKeyword sep lcIdentifier optsep
                                   \"{\" stmtsep
                                   oidStatement stmtsep
                                   *1(representsStatement stmtsep)
                                   statusStatement stmtsep
                                   *1(descriptionStatement stmtsep)
                                   *1(referenceStatement stmtsep)
                               \"}\" optsep \";\"

     representsStatement     = representsKeyword sep
                                   qucIdentifier optsep \";\"

     scalarsStatement        = scalarsKeyword sep lcIdentifier optsep
                                   \"{\" stmtsep
                                   oidStatement stmtsep
                                   1*(objectStatement stmtsep)
                                   statusStatement stmtsep
                                   descriptionStatement stmtsep
                                   *1(referenceStatement stmtsep)
                               \"}\" optsep \";\"

     tableStatement          = tableKeyword sep lcIdentifier optsep
                                   \"{\" stmtsep
                                   oidStatement stmtsep

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                                   anyIndexStatement stmtsep
                                   *1(createStatement stmtsep)
                                   1*(objectStatement stmtsep)
                                   statusStatement stmtsep
                                   descriptionStatement stmtsep
                                   *1(referenceStatement stmtsep)
                               \"}\" optsep \";\"

     objectStatement         = objectKeyword sep lcIdentifier optsep
                                   \"{\" stmtsep
                                   implementsStatement stmtsep
                                   *1(subidStatement stmtsep)
                                   *1(statusStatement stmtsep)
                                   *1(descriptionStatement stmtsep)
                                   *1(referenceStatement stmtsep)
                               \"}\" optsep \";\"

     implementsStatement     = implementsKeyword sep qcattrIdentifier
                                   optsep \";\"

     notificationStatement   = notificationKeyword sep lcIdentifier
                                   optsep \"{\" stmtsep
                                   oidStatement stmtsep
                                   signalsStatement stmtsep
                                   statusStatement stmtsep
                                   descriptionStatement stmtsep
                                   *1(referenceStatement stmtsep)
                               \"}\" optsep \";\"

     signalsStatement        = signalsKeyword sep qattrIdentifier
                                   optsep \"{\" stmtsep
                                   *(signalsObjectStatement)
                               \"}\" optsep \";\"

     signalsObjectStatement  = objectKeyword sep
                                   qattrIdentifier optsep \";\"

     groupStatement          = groupKeyword sep lcIdentifier optsep
                                   \"{\" stmtsep
                                   oidStatement stmtsep
                                   membersStatement stmtsep
                                   statusStatement stmtsep
                                   descriptionStatement stmtsep
                                   *1(referenceStatement stmtsep)
                               \"}\" optsep \";\"

     complianceStatement     = complianceKeyword sep lcIdentifier optsep
                                   \"{\" stmtsep

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                                   oidStatement stmtsep
                                   statusStatement stmtsep
                                   descriptionStatement stmtsep
                                   *1(referenceStatement stmtsep)
                                   *1(mandatoryStatement stmtsep)
                                   *(optionalStatement stmtsep)
                                   *(refineStatement stmtsep)
                               \"}\" optsep \";\"

     anyIndexStatement       = indexStatement /
                               augmentsStatement /
                               reordersStatement /
                               extendsStatement /
                               expandsStatement

     indexStatement          = indexKeyword *1(sep impliedKeyword) optsep
                                   \"(\" optsep qlcIdentifierList
                                   optsep \")\" optsep \";\"

     augmentsStatement       = augmentsKeyword sep qlcIdentifier
                                   optsep \";\"

     reordersStatement       = reordersKeyword sep qlcIdentifier
                                   *1(sep impliedKeyword)
                                   optsep \"(\" optsep
                                   qlcIdentifierList optsep \")\"
                                   optsep \";\"

     extendsStatement        = extendsKeyword sep qlcIdentifier optsep \";\"

     expandsStatement        = expandsKeyword sep qlcIdentifier
                                   *1(sep impliedKeyword)
                                   optsep \"(\" optsep
                                   qlcIdentifierList optsep \")\"
                                   optsep \";\"

     createStatement         = createKeyword optsep \";\"

     membersStatement        = membersKeyword optsep \"(\" optsep
                                   qlcIdentifierList optsep
                                   \")\" optsep \";\"

     mandatoryStatement      = mandatoryKeyword optsep \"(\" optsep
                                   qlcIdentifierList optsep
                                   \")\" optsep \";\"

     optionalStatement       = optionalKeyword sep qlcIdentifier optsep
                                   \"{\" descriptionStatement stmtsep

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    RFC 3781                 SMIng Mappings to SNMP                 May 2004

                               \"}\" optsep \";\"

     refineStatement         = refineKeyword sep qlcIdentifier optsep \"{\"
                                   *1(typeStatement stmtsep)
                                   *1(writetypeStatement stmtsep)
                                   *1(accessStatement stmtsep)
                                   descriptionStatement stmtsep
                               \"}\" optsep \";\"

     typeStatement           = typeKeyword sep
                                   (refinedBaseType / refinedType)
                                   optsep \";\"

     writetypeStatement      = writetypeKeyword sep
                                   (refinedBaseType / refinedType)
                                   optsep \";\"

     oidStatement            = oidKeyword sep objectIdentifier optsep \";\"

     subidStatement          = subidKeyword sep subid optsep \";\"

     ;;
     ;; Statement keywords.
     ;;

     snmpKeyword         =  %x73 %x6E %x6D %x70
     nodeKeyword         =  %x6E %x6F %x64 %x65
     representsKeyword   =  %x72 %x65 %x70 %x72 %x65 %x73 %x65 %x6E %x74
                            %x73
     scalarsKeyword      =  %x73 %x63 %x61 %x6C %x61 %x72 %x73
     tableKeyword        =  %x74 %x61 %x62 %x6C %x65
     implementsKeyword   =  %x69 %x6D %x70 %x6C %x65 %x6D %x65 %x6E %x74
                            %x73
     subidKeyword        =  %x73 %x75 %x62 %x69 %x64
     objectKeyword       =  %x6F %x62 %x6A %x65 %x63 %x74
     notificationKeyword =  %x6E %x6F %x74 %x69 %x66 %x69 %x63 %x61 %x74
                            %x69 %x6F %x6E
     signalsKeyword      =  %x73 %x69 %x67 %x6E %x61 %x6C %x73
     oidKeyword          =  %x6F %x69 %x64
     groupKeyword        =  %x67 %x72 %x6F %x75 %x70
     complianceKeyword   =  %x63 %x6F %x6D %x70 %x6C %x69 %x61 %x6E %x63
                            %x65
     impliedKeyword      =  %x69 %x6D %x70 %x6C %x69 %x65 %x64
     indexKeyword        =  %x69 %x6E %x64 %x65 %x78
     augmentsKeyword     =  %x61 %x75 %x67 %x6D %x65 %x6E %x74 %x73
     reordersKeyword     =  %x72 %x65 %x6F %x72 %x64 %x65 %x72 %x73
     extendsKeyword      =  %x65 %x78 %x74 %x65 %x6E %x64 %x73
     expandsKeyword      =  %x65 %x78 %x70 %x61 %x6E %x64 %x73

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    RFC 3781                 SMIng Mappings to SNMP                 May 2004

     createKeyword       =  %x63 %x72 %x65 %x61 %x74 %x65
     membersKeyword      =  %x6D %x65 %x6D %x62 %x65 %x72 %x73
     mandatoryKeyword    =  %x6D %x61 %x6E %x64 %x61 %x74 %x6F %x72 %x79
     optionalKeyword     =  %x6F %x70 %x74 %x69 %x6F %x6E %x61 %x6C
     refineKeyword       =  %x72 %x65 %x66 %x69 %x6E %x65
     writetypeKeyword    =  %x77 %x72 %x69 %x74 %x65 %x74 %x79 %x70 %x65

     ;; End of ABNF
                   ";
         };
         //
         //
         //

         snmp {

             node ccitt                       { oid 0;          };

             node   zeroDotZero {
                 oid         0.0;
                 description "A null value used for pointers.";
             };

             node iso                         { oid 1;          };
             node   org                       { oid iso.3;      };
             node     dod                     { oid org.6;      };
             node       internet              { oid dod.1;      };
             node         directory           { oid internet.1; };
             node         mgmt                { oid internet.2; };
             node           mib-2             { oid mgmt.1;     };
             node             transmission    { oid mib-2.10;   };
             node         experimental        { oid internet.3; };
             node         private             { oid internet.4; };
             node           enterprises       { oid private.1;  };
             node         security            { oid internet.5; };
             node         snmpV2              { oid internet.6; };
             node           snmpDomains       { oid snmpV2.1;   };
             node           snmpProxys        { oid snmpV2.2;   };
             node           snmpModules       { oid snmpV2.3;   };

             node joint-iso-ccitt             { oid 2;          };

             status          current;
             description
                "This set of nodes defines the core object
                 identifier hierarchy";
             reference
                "RFC 2578, Section 2.";

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         };

     };

    6.  NMRG-SMING-SNMP

       The module NMRG-SMING-SNMP specified below defines derived types that
       are specific to the SNMP mapping.

    module NMRG-SMING-SNMP {

        organization    "IRTF Network Management Research Group (NMRG)";

        contact         "IRTF Network Management Research Group (NMRG)
                         http://www.ibr.cs.tu-bs.de/projects/nmrg/

                         Frank Strauss
                         TU Braunschweig
                         Muehlenpfordtstrasse 23
                         38106 Braunschweig
                         Germany
                         Phone: +49 531 391 3266
                         EMail: strauss@ibr.cs.tu-bs.de

                         Juergen Schoenwaelder
                         International University Bremen
                         P.O. Box 750 561
                         28725 Bremen
                         Germany
                         Phone: +49 421 200 3587
                         EMail: j.schoenwaelder@iu-bremen.de";

        description     "Core type definitions for the SMIng SNMP mapping.
                         These definitions are based on RFC 2579 definitions
                         that are specific to the SNMP protocol and its
                         naming system.

                         Copyright (C) The Internet Society (2004).
                         All Rights Reserved.
                         This version of this module is part of
                         RFC 3781, see the RFC itself for full
                         legal notices.";

        revision {
            date        "2003-12-16";
            description "Initial version, published as RFC 3781.";
        };

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        typedef TestAndIncr {
            type        Integer32 (0..2147483647);
            description
                "Represents integer-valued information used for atomic
                 operations.  When the management protocol is used to
                 specify that an object instance having this type is to
                 be modified, the new value supplied via the management
                 protocol must precisely match the value presently held by
                 the instance.  If not, the management protocol set
                 operation fails with an error of `inconsistentValue'.
                 Otherwise, if the current value is the maximum value of
                 2^31-1 (2147483647 decimal), then the value held by the
                 instance is wrapped to zero; otherwise, the value held by
                 the instance is incremented by one.  (Note that
                 regardless of whether the management protocol set
                 operation succeeds, the variable-binding in the request
                 and response PDUs are identical.)

                 The value of the SNMP access clause for objects having
                 this type has to be `readwrite'.  When an instance of a
                 columnar object having this type is created, any value
                 may be supplied via the management protocol.

                 When the network management portion of the system is re-
                 initialized, the value of every object instance having
                 this type must either be incremented from its value prior
                 to the re-initialization, or (if the value prior to the
                 re-initialization is unknown) be set to a
                 pseudo-randomly generated value."; };

        typedef AutonomousType {
            type        Pointer;
            description
                "Represents an independently extensible type
                 identification value.  It may, for example, indicate a
                 particular OID sub-tree with further MIB definitions, or
                 define a particular type of protocol or hardware.";
        };

        typedef VariablePointer {
            type        Pointer;
            description
                "A pointer to a specific object instance.  For example,
                 sysContact.0 or ifInOctets.3.";
        };

        typedef RowPointer {
            type        Pointer;

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            description
                "Represents a pointer to a conceptual row.  The value is
                 the name of the instance of the first accessible columnar
                 object in the conceptual row.

                 For example, ifIndex.3 would point to the 3rd row in the
                 ifTable (note that if ifIndex were not-accessible, then
                 ifDescr.3 would be used instead).";
        };

        typedef RowStatus {
            type        Enumeration (active(1), notInService(2),
                            notReady(3), createAndGo(4),
                            createAndWait(5), destroy(6));
            description
            "The RowStatus type is used to manage the creation and
             deletion of conceptual rows, and is used as the type for the
             row status column of a conceptual row.

             The status column has six defined values:

                 - `active', which indicates that the conceptual row is
                 available for use by the managed device;

                 - `notInService', which indicates that the conceptual
                 row exists in the agent, but is unavailable for use by
                 the managed device (see NOTE below);

                 - `notReady', which indicates that the conceptual row
                 exists in the agent, but is missing information
                 necessary in order to be available for use by the
                 managed device;

                 - `createAndGo', which is supplied by a management
                 station wishing to create a new instance of a
                 conceptual row and to have its status automatically set
                 to active, making it available for use by the managed
                 device;

                 - `createAndWait', which is supplied by a management
                 station wishing to create a new instance of a
                 conceptual row (but not make it available for use by
                 the managed device); and,

                 - `destroy', which is supplied by a management station
                 wishing to delete all of the instances associated with
                 an existing conceptual row.

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    RFC 3781                 SMIng Mappings to SNMP                 May 2004

             Whereas five of the six values (all except `notReady') may
             be specified in a management protocol set operation, only
             three values will be returned in response to a management
             protocol retrieval operation: `notReady', `notInService' or
             `active'.  That is, when queried, an existing conceptual row
             has only three states: it is either available for use by the
             managed device (the status column has value `active'); it is
             not available for use by the managed device, though the
             agent has sufficient information to make it so (the status
             column has value `notInService'); or, it is not available
             for use by the managed device, and an attempt to make it so
             would fail because the agent has insufficient information
             (the state column has value `notReady').

                                     NOTE WELL

                 This textual convention may be used for a MIB table,
                 irrespective of whether the values of that table's
                 conceptual rows are able to be modified while it is
                 active, or whether its conceptual rows must be taken
                 out of service in order to be modified.  That is, it is
                 the responsibility of the DESCRIPTION clause of the
                 status column to specify whether the status column must
                 not be `active' in order for the value of some other
                 column of the same conceptual row to be modified.  If
                 such a specification is made, affected columns may be
                 changed by an SNMP set PDU if the RowStatus would not
                 be equal to `active' either immediately before or after
                 processing the PDU.  In other words, if the PDU also
                 contained a varbind that would change the RowStatus
                 value, the column in question may be changed if the
                 RowStatus was not equal to `active' as the PDU was
                 received, or if the varbind sets the status to a value
                 other than 'active'.

             Also note that whenever any elements of a row exist, the
             RowStatus column must also exist.

             To summarize the effect of having a conceptual row with a
             column having a type of RowStatus, consider the following
             state diagram:

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    RFC 3781                 SMIng Mappings to SNMP                 May 2004

                                             STATE
                  +--------------+-----------+-------------+-------------
                  |      A       |     B     |      C      |      D
                  |              |status col.|status column|
                  |status column |    is     |      is     |status column
        ACTION    |does not exist|  notReady | notInService|  is active
    --------------+--------------+-----------+-------------+-------------
    set status    |noError    ->D|inconsist- |inconsistent-|inconsistent-
    column to     |       or     |   entValue|        Value|        Value
    createAndGo   |inconsistent- |           |             |
                  |         Value|           |             |
    --------------+--------------+-----------+-------------+-------------
    set status    |noError  see 1|inconsist- |inconsistent-|inconsistent-
    column to     |       or     |   entValue|        Value|        Value
    createAndWait |wrongValue    |           |             |
    --------------+--------------+-----------+-------------+-------------
    set status    |inconsistent- |inconsist- |noError      |noError
    column to     |         Value|   entValue|             |
    active        |              |           |             |
                  |              |     or    |             |
                  |              |           |             |
                  |              |see 2   ->D|see 8     ->D|          ->D
    --------------+--------------+-----------+-------------+-------------
    set status    |inconsistent- |inconsist- |noError      |noError   ->C
    column to     |         Value|   entValue|             |
    notInService  |              |           |             |
                  |              |     or    |             |      or
                  |              |           |             |
                  |              |see 3   ->C|          ->C|see 6
    --------------+--------------+-----------+-------------+-------------
    set status    |noError       |noError    |noError      |noError   ->A
    column to     |              |           |             |      or
    destroy       |           ->A|        ->A|          ->A|see 7
    --------------+--------------+-----------+-------------+-------------
    set any other |see 4         |noError    |noError      |see 5
    column to some|              |           |             |
    value         |              |      see 1|          ->C|          ->D
    --------------+--------------+-----------+-------------+-------------

             (1) go to B or C, depending on information available to the
             agent.

             (2) if other variable bindings included in the same PDU,
             provide values for all columns which are missing but
             required, then return noError and goto D.

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    RFC 3781                 SMIng Mappings to SNMP                 May 2004

             (3) if other variable bindings included in the same PDU,
             provide values for all columns which are missing but
             required, then return noError and goto C.

             (4) at the discretion of the agent, the return value may be
             either:

                 inconsistentName: because the agent does not choose to
                 create such an instance when the corresponding
                 RowStatus instance does not exist, or

                 inconsistentValue: if the supplied value is
                 inconsistent with the state of some other MIB object's
                 value, or

                 noError: because the agent chooses to create the
                 instance.

             If noError is returned, then the instance of the status
             column must also be created, and the new state is B or C,
             depending on the information available to the agent.  If
             inconsistentName or inconsistentValue is returned, the row
             remains in state A.

             (5) depending on the MIB definition for the column/table,
             either noError or inconsistentValue may be returned.

             (6) the return value can indicate one of the following
             errors:

                 wrongValue: because the agent does not support
                 createAndWait, or

                 inconsistentValue: because the agent is unable to take
                 the row out of service at this time, perhaps because it
                 is in use and cannot be de-activated.

             (7) the return value can indicate the following error:

                 inconsistentValue: because the agent is unable to
                 remove the row at this time, perhaps because it is in
                 use and cannot be de-activated.

             NOTE: Other processing of the set request may result in a
             response other than noError being returned, e.g.,
             wrongValue, noCreation, etc.

    Strauss & Schoenwaelder       Experimental                     [Page 38]

    RFC 3781                 SMIng Mappings to SNMP                 May 2004

                              Conceptual Row Creation

             There are four potential interactions when creating a
             conceptual row: selecting an instance-identifier which is
             not in use; creating the conceptual row; initializing any
             objects for which the agent does not supply a default; and,
             making the conceptual row available for use by the managed
             device.

             Interaction 1: Selecting an Instance-Identifier

             The algorithm used to select an instance-identifier varies
             for each conceptual row.  In some cases, the instance-
             identifier is semantically significant, e.g., the
             destination address of a route, and a management station
             selects the instance-identifier according to the semantics.

             In other cases, the instance-identifier is used solely to
             distinguish conceptual rows, and a management station
             without specific knowledge of the conceptual row might
             examine the instances present in order to determine an
             unused instance-identifier.  (This approach may be used, but
             it is often highly sub-optimal; however, it is also a
             questionable practice for a naive management station to
             attempt conceptual row creation.)

             Alternately, the MIB module which defines the conceptual row
             might provide one or more objects which provide assistance
             in determining an unused instance-identifier.  For example,
             if the conceptual row is indexed by an integer-value, then
             an object having an integer-valued SYNTAX clause might be
             defined for such a purpose, allowing a management station to
             issue a management protocol retrieval operation.  In order
             to avoid unnecessary collisions between competing management
             stations, `adjacent' retrievals of this object should be
             different.

             Finally, the management station could select a pseudo-random
             number to use as the index.  In the event that this index
             was already in use and an inconsistentValue was returned in
             response to the management protocol set operation, the
             management station should simply select a new pseudo-random
             number and retry the operation.

             A MIB designer should choose between the two latter
             algorithms based on the size of the table (and therefore the
             efficiency of each algorithm).  For tables in which a large
             number of entries are expected, it is recommended that a MIB

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    RFC 3781                 SMIng Mappings to SNMP                 May 2004

             object be defined that returns an acceptable index for
             creation.  For tables with small numbers of entries, it is
             recommended that the latter pseudo-random index mechanism be
             used.

             Interaction 2: Creating the Conceptual Row

             Once an unused instance-identifier has been selected, the
             management station determines if it wishes to create and
             activate the conceptual row in one transaction or in a
             negotiated set of interactions.

             Interaction 2a: Creating and Activating the Conceptual Row

             The management station must first determine the column
             requirements, i.e., it must determine those columns for
             which it must or must not provide values.  Depending on the
             complexity of the table and the management station's
             knowledge of the agent's capabilities, this determination
             can be made locally by the management station.  Alternately,
             the management station issues a management protocol get
             operation to examine all columns in the conceptual row that
             it wishes to create.  In response, for each column, there
             are three possible outcomes:

                 - a value is returned, indicating that some other
                 management station has already created this conceptual
                 row.  We return to interaction 1.

                 - the exception `noSuchInstance' is returned,
                 indicating that the agent implements the object-type
                 associated with this column, and that this column in at
                 least one conceptual row would be accessible in the MIB
                 view used by the retrieval were it to exist. For those
                 columns to which the agent provides read-create access,
                 the `noSuchInstance' exception tells the management
                 station that it should supply a value for this column
                 when the conceptual row is to be created.

                 - the exception `noSuchObject' is returned, indicating
                 that the agent does not implement the object-type
                 associated with this column or that there is no
                 conceptual row for which this column would be
                 accessible in the MIB view used by the retrieval.  As
                 such, the management station can not issue any
                 management protocol set operations to create an
                 instance of this column.

    Strauss & Schoenwaelder       Experimental                     [Page 40]

    RFC 3781                 SMIng Mappings to SNMP                 May 2004

             Once the column requirements have been determined, a
             management protocol set operation is accordingly issued.
             This operation also sets the new instance of the status
             column to `createAndGo'.

             When the agent processes the set operation, it verifies that
             it has sufficient information to make the conceptual row
             available for use by the managed device.  The information
             available to the agent is provided by two sources: the
             management protocol set operation which creates the
             conceptual row, and, implementation-specific defaults
             supplied by the agent (note that an agent must provide
             implementation-specific defaults for at least those objects
             which it implements as read-only).  If there is sufficient
             information available, then the conceptual row is created, a
             `noError' response is returned, the status column is set to
             `active', and no further interactions are necessary (i.e.,
             interactions 3 and 4 are skipped).  If there is insufficient
             information, then the conceptual row is not created, and the
             set operation fails with an error of `inconsistentValue'.
             On this error, the management station can issue a management
             protocol retrieval operation to determine if this was
             because it failed to specify a value for a required column,
             or, because the selected instance of the status column
             already existed.  In the latter case, we return to
             interaction 1.  In the former case, the management station
             can re-issue the set operation with the additional
             information, or begin interaction 2 again using
             `createAndWait' in order to negotiate creation of the
             conceptual row.

                                     NOTE WELL

                 Regardless of the method used to determine the column
                 requirements, it is possible that the management
                 station might deem a column necessary when, in fact,
                 the agent will not allow that particular columnar
                 instance to be created or written.  In this case, the
                 management protocol set operation will fail with an
                 error such as `noCreation' or `notWritable'.  In this
                 case, the management station decides whether it needs
                 to be able to set a value for that particular columnar
                 instance.  If not, the management station re-issues the
                 management protocol set operation, but without setting

    Strauss & Schoenwaelder       Experimental                     [Page 41]

    RFC 3781                 SMIng Mappings to SNMP                 May 2004

                 a value for that particular columnar instance;
                 otherwise, the management station aborts the row
                 creation algorithm.

             Interaction 2b: Negotiating the Creation of the Conceptual
             Row

             The management station issues a management protocol set
             operation which sets the desired instance of the status
             column to `createAndWait'.  If the agent is unwilling to
             process a request of this sort, the set operation fails with
             an error of `wrongValue'.  (As a consequence, such an agent
             must be prepared to accept a single management protocol set
             operation, i.e., interaction 2a above, containing all of the
             columns indicated by its column requirements.) Otherwise,
             the conceptual row is created, a `noError' response is
             returned, and the status column is immediately set to either
             `notInService' or `notReady', depending on whether it has
             sufficient information to make the conceptual row available
             for use by the managed device.  If there is sufficient
             information available, then the status column is set to
             `notInService'; otherwise, if there is insufficient
             information, then the status column is set to `notReady'.
             Regardless, we proceed to interaction 3.

             Interaction 3: Initializing non-defaulted Objects

             The management station must now determine the column
             requirements.  It issues a management protocol get operation
             to examine all columns in the created conceptual row.  In
             the response, for each column, there are three possible
             outcomes:

                 - a value is returned, indicating that the agent
                 implements the object-type associated with this column
                 and had sufficient information to provide a value.  For
                 those columns to which the agent provides read-create
                 access (and for which the agent allows their values to
                 be changed after their creation), a value return tells
                 the management station that it may issue additional
                 management protocol set operations, if it desires, in
                 order to change the value associated with this column.

                 - the exception `noSuchInstance' is returned,
                 indicating that the agent implements the object-type
                 associated with this column, and that this column in at
                 least one conceptual row would be accessible in the MIB
                 view used by the retrieval were it to exist. However,

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                 the agent does not have sufficient information to
                 provide a value, and until a value is provided, the
                 conceptual row may not be made available for use by the
                 managed device.  For those columns to which the agent
                 provides read-create access, the `noSuchInstance'
                 exception tells the management station that it must
                 issue additional management protocol set operations, in
                 order to provide a value associated with this column.

                 - the exception `noSuchObject' is returned, indicating
                 that the agent does not implement the object-type
                 associated with this column or that there is no
                 conceptual row for which this column would be
                 accessible in the MIB view used by the retrieval.  As
                 such, the management station can not issue any
                 management protocol set operations to create an
                 instance of this column.

             If the value associated with the status column is
             `notReady', then the management station must first deal with
             all `noSuchInstance' columns, if any.  Having done so, the
             value of the status column becomes `notInService', and we
             proceed to interaction 4.

             Interaction 4: Making the Conceptual Row Available

             Once the management station is satisfied with the values
             associated with the columns of the conceptual row, it issues
             a management protocol set operation to set the status column
             to `active'.  If the agent has sufficient information to
             make the conceptual row available for use by the managed
             device, the management protocol set operation succeeds (a
             `noError' response is returned).  Otherwise, the management
             protocol set operation fails with an error of
             `inconsistentValue'.

                                     NOTE WELL

                 A conceptual row having a status column with value
                 `notInService' or `notReady' is unavailable to the
                 managed device.  As such, it is possible for the
                 managed device to create its own instances during the
                 time between the management protocol set operation
                 which sets the status column to `createAndWait' and the
                 management protocol set operation which sets the status
                 column to `active'.  In this case, when the management
                 protocol set operation is issued to set the status
                 column to `active', the values held in the agent

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                 supersede those used by the managed device.

             If the management station is prevented from setting the
             status column to `active' (e.g., due to management station or
             network failure) the conceptual row will be left in the
             `notInService' or `notReady' state, consuming resources
             indefinitely.  The agent must detect conceptual rows that
             have been in either state for an abnormally long period of
             time and remove them.  It is the responsibility of the
             DESCRIPTION clause of the status column to indicate what an
             abnormally long period of time would be.  This period of time
             should be long enough to allow for human response time
             (including `think time') between the creation of the
             conceptual row and the setting of the status to `active'.  In
             the absence of such information in the DESCRIPTION clause, it
             is suggested that this period be approximately 5 minutes in
             length.  This removal action applies not only to newly-
             created rows, but also to previously active rows which are
             set to, and left in, the notInService state for a prolonged
             period exceeding that which is considered normal for such a
             conceptual row.

                             Conceptual Row Suspension

             When a conceptual row is `active', the management station
             may issue a management protocol set operation which sets the
             instance of the status column to `notInService'.  If the
             agent is unwilling to do so, the set operation fails with an
             error of `wrongValue' or `inconsistentValue'.
             Otherwise, the conceptual row is taken out of service, and a
             `noError' response is returned.  It is the responsibility of
             the DESCRIPTION clause of the status column to indicate
             under what circumstances the status column should be taken
             out of service (e.g., in order for the value of some other
             column of the same conceptual row to be modified).

                              Conceptual Row Deletion

             For deletion of conceptual rows, a management protocol set
             operation is issued which sets the instance of the status
             column to `destroy'.  This request may be made regardless of
             the current value of the status column (e.g., it is possible
             to delete conceptual rows which are either `notReady',
             `notInService' or `active'.) If the operation succeeds, then
             all instances associated with the conceptual row are
             immediately removed.";
        };

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        typedef StorageType {
            type        Enumeration (other(1), volatile(2),
                            nonVolatile(3), permanent(4),
                            readOnly(5));
            description
                "Describes the memory realization of a conceptual row.  A
                 row which is volatile(2) is lost upon reboot.  A row
                 which is either nonVolatile(3), permanent(4) or
                 readOnly(5), is backed up by stable storage.  A row which
                 is permanent(4) can be changed but not deleted.  A row
                 which is readOnly(5) cannot be changed nor deleted.

                 If the value of an object with this syntax is either
                 permanent(4) or readOnly(5), it cannot be modified.
                 Conversely, if the value is either other(1), volatile(2)
                 or nonVolatile(3), it cannot be modified to be
                 permanent(4) or readOnly(5).  (All illegal modifications
                 result in a 'wrongValue' error.)

                 Every usage of this textual convention is required to
                 specify the columnar objects which a permanent(4) row
                 must at a minimum allow to be writable.";
        };

        typedef TDomain {
            type        Pointer;
            description
                "Denotes a kind of transport service.

                 Some possible values, such as snmpUDPDomain, are defined
                 in the SNMPv2-TM MIB module.  Other possible values are
                 defined in other MIB modules."
            reference
                "The SNMPv2-TM MIB module is defined in RFC 3417."
        };

        typedef TAddressOrZero {
            type        OctetString (0..255);
            description
                "Denotes a transport service address.

                 A TAddress value is always interpreted within the context
                 of a TDomain value.  Thus, each definition of a TDomain
                 value must be accompanied by a definition of a textual
                 convention for use with that TDomain.  Some possible
                 textual conventions, such as SnmpUDPAddress for
                 snmpUDPDomain, are defined in the SNMPv2-TM MIB module.
                 Other possible textual conventions are defined in other

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                 MIB modules.

                 A zero-length TAddress value denotes an unknown transport
                 service address."
            reference
                "The SNMPv2-TM MIB module is defined in RFC 3417."
        };

        typedef TAddress {
            type        TAddressOrZero (1..255);
            description
                "Denotes a transport service address.

                 This type does not allow a zero-length TAddress value."
        };

    };

    7.  Security Considerations

       This document presents an extension of the SMIng data definition
       language which supports the mapping of SMIng data definitions so that
       they can be used with the SNMP management framework.  The language
       extension and the mapping itself has no security impact on the
       Internet.

    8.  Acknowledgements

       Since SMIng started as a close successor of SMIv2, some paragraphs
       and phrases are directly taken from the SMIv2 specifications
       [RFC2578], [RFC2579], [RFC2580] written by Jeff Case, Keith
       McCloghrie, David Perkins, Marshall T.  Rose, Juergen Schoenwaelder,
       and Steven L. Waldbusser.

       The authors would like to thank all participants of the 7th NMRG
       meeting held in Schloss Kleinheubach from 6-8 September 2000, which
       was a major step towards the current status of this memo, namely
       Heiko Dassow, David Durham, Keith McCloghrie, and Bert Wijnen.

       Furthermore, several discussions within the SMING Working Group
       reflected experience with SMIv2 and influenced this specification at
       some points.

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    9. References

    9.1.  Normative References

       [RFC3780]  Strauss, F. and J. Schoenwaelder, "SMIng - Next Generation
                  Structure of Management Information", RFC 3780, May 2004.

       [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
                  Requirement Levels", BCP 14, RFC 2119, March 1997.

       [RFC2234]  Crocker, D. and P. Overell, "Augmented BNF for Syntax
                  Specifications: ABNF", RFC 2234, November 1997.

    9.2.  Informative References

       [RFC3410]  Case, J., Mundy, R., Partain, D. and B. Stewart,
                  "Introduction and Applicability Statements for Internet
                  Standard Management Framework", RFC 3410, December 2002.

       [RFC2578]  McCloghrie, K., Perkins, D. and J. Schoenwaelder,
                  "Structure of Management Information Version 2 (SMIv2)",
                  STD 58, RFC 2578, April 1999.

       [RFC2579]  McCloghrie, K., Perkins, D. and J. Schoenwaelder, "Textual
                  Conventions for SMIv2", STD 59, RFC 2579, April 1999.

       [RFC2580]  McCloghrie, K., Perkins, D. and J. Schoenwaelder,
                  "Conformance Statements for SMIv2", STD 60, RFC 2580,
                  April 1999.

       [ASN1]     International Organization for Standardization,
                  "Specification of Abstract Syntax Notation One (ASN.1)",
                  International Standard 8824, December 1987.

       [RFC3159]  McCloghrie, K., Fine, M., Seligson, J., Chan, K., Hahn,
                  S., Sahita, R., Smith, A. and F. Reichmeyer, "Structure of
                  Policy Provisioning Information (SPPI)", RFC 3159, August
                  2001.

       [IEEE754]  Institute of Electrical and Electronics Engineers, "IEEE
                  Standard for Binary Floating-Point Arithmetic", ANSI/IEEE
                  Standard 754-1985, August 1985.

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    RFC 3781                 SMIng Mappings to SNMP                 May 2004

       [RFC3418]  Presuhn, R., Case, J., McCloghrie, K., Rose, M. and S.
                  Waldbusser, "Management Information Base (MIB) for the
                  Simple Network Management Protocol (SNMP)", STD 62, RFC
                  3418, December 2002.

       [RFC3416]  Presuhn, R., Case, J., McCloghrie, K., Rose, M. and S.
                  Waldbusser, "Version 2 of the Protocol Operations for the
                  Simple  Network Management Protocol (SNMP)", STD 62, RFC
                  3416, December 2002.

    Authors' Addresses

       Frank Strauss
       TU Braunschweig
       Muehlenpfordtstrasse 23
       38106 Braunschweig
       Germany

       Phone: +49 531 391 3266
       EMail: strauss@ibr.cs.tu-bs.de
       URI:   http://www.ibr.cs.tu-bs.de/

       Juergen Schoenwaelder
       International University Bremen
       P.O. Box 750 561
       28725 Bremen
       Germany

       Phone: +49 421 200 3587
       EMail: j.schoenwaelder@iu-bremen.de
       URI:   http://www.eecs.iu-bremen.de/

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    Full Copyright Statement

       Copyright (C) The Internet Society (2004).  This document is subject
       to the rights, licenses and restrictions contained in BCP 78, and
       except as set forth therein, the authors retain all their rights.

       This document and the information contained herein are provided on an
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    Acknowledgement

       Funding for the RFC Editor function is currently provided by the
       Internet Society.

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