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Network Working Group                                         F. Strauss
Internet-Draft                                          J. Schoenwaelder
Expires: January 18, 2002                                TU Braunschweig
                                                           July 20, 2001


                         SMIng Mappings to SNMP
                        draft-ietf-sming-snmp-02

Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on January 18, 2002.

Copyright Notice

   Copyright (C) The Internet Society (2001).  All Rights Reserved.

Abstract

   This memo presents an SMIng language extension that supports 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.









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Table of Contents

   1.      Introduction . . . . . . . . . . . . . . . . . . . . . . .  5
   2.      SNMP Based Internet Management . . . . . . . . . . . . . .  5
   2.1     Kinds of Nodes . . . . . . . . . . . . . . . . . . . . . .  6
   2.2     Scalar and Columnar Object Instances . . . . . . . . . . .  7
   2.3     Object Identifier Hierarchy  . . . . . . . . . . . . . . .  8
   3.      SMIng Data Type Mappings . . . . . . . . . . . . . . . . .  9
   3.1     ASN.1 Definitions  . . . . . . . . . . . . . . . . . . . . 11
   4.      The snmp Extension Statement . . . . . . . . . . . . . . . 11
   4.1     The oid Statement  . . . . . . . . . . . . . . . . . . . . 12
   4.2     The node Statement . . . . . . . . . . . . . . . . . . . . 12
   4.2.1   The node's oid Statement . . . . . . . . . . . . . . . . . 12
   4.2.2   The node's represents Statement  . . . . . . . . . . . . . 12
   4.2.3   The node's status Statement  . . . . . . . . . . . . . . . 12
   4.2.4   The node's description Statement . . . . . . . . . . . . . 13
   4.2.5   The node's reference Statement . . . . . . . . . . . . . . 13
   4.2.6   Usage Examples . . . . . . . . . . . . . . . . . . . . . . 13
   4.3     The scalars Statement  . . . . . . . . . . . . . . . . . . 13
   4.3.1   The scalars' oid Statement . . . . . . . . . . . . . . . . 13
   4.3.2   The scalars' implements Statement  . . . . . . . . . . . . 14
   4.3.2.1 The implements' object Statement . . . . . . . . . . . . . 14
   4.3.3   The scalars' status Statement  . . . . . . . . . . . . . . 14
   4.3.4   The scalars' description Statement . . . . . . . . . . . . 14
   4.3.5   The scalars' reference Statement . . . . . . . . . . . . . 15
   4.3.6   Usage Example  . . . . . . . . . . . . . . . . . . . . . . 15
   4.4     The table Statement  . . . . . . . . . . . . . . . . . . . 15
   4.4.1   The table's oid Statement  . . . . . . . . . . . . . . . . 15
   4.4.2   Table Indexing Statements  . . . . . . . . . . . . . . . . 15
   4.4.2.1 The table's index Statement for Table Indexing . . . . . . 16
   4.4.2.2 The table's augments Statement for Table Indexing  . . . . 16
   4.4.2.3 The table's extends Statement for Table Indexing . . . . . 16
   4.4.2.4 The table's reorders Statement for Table Indexing  . . . . 17
   4.4.2.5 The table's expands Statement for Table Indexing . . . . . 17
   4.4.3   The table's create Statement . . . . . . . . . . . . . . . 18
   4.4.4   The table's implements Statement . . . . . . . . . . . . . 18
   4.4.4.1 The implements' object Statement . . . . . . . . . . . . . 18
   4.4.5   The table's status Statement . . . . . . . . . . . . . . . 18
   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 . . . . . . . . . . . . . . . . 19
   4.5.1   The notification's oid Statement . . . . . . . . . . . . . 20
   4.5.2   The notification's signals Statement . . . . . . . . . . . 20
   4.5.2.1 The signals' object Statement  . . . . . . . . . . . . . . 20
   4.5.3   The notification's status Statement  . . . . . . . . . . . 20
   4.5.4   The notification's description Statement . . . . . . . . . 20
   4.5.5   The notification's reference Statement . . . . . . . . . . 20



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   4.5.6   Usage Example  . . . . . . . . . . . . . . . . . . . . . . 21
   4.6     The group Statement  . . . . . . . . . . . . . . . . . . . 21
   4.6.1   The group's oid Statement  . . . . . . . . . . . . . . . . 21
   4.6.2   The group's members Statement  . . . . . . . . . . . . . . 21
   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 . . . . . . . . . . . . . . . . . 22
   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 . . . . . . . . . . . 23
   4.7.6   The compliance's optional Statement  . . . . . . . . . . . 24
   4.7.6.1 The optional's description Statement . . . . . . . . . . . 24
   4.7.7   The compliance's refine Statement  . . . . . . . . . . . . 24
   4.7.7.1 The refine's type Statement  . . . . . . . . . . . . . . . 24
   4.7.7.2 The refine's writetype Statement . . . . . . . . . . . . . 25
   4.7.7.3 The refine's access Statement  . . . . . . . . . . . . . . 25
   4.7.7.4 The refine's description Statement . . . . . . . . . . . . 25
   4.7.8   Usage Example  . . . . . . . . . . . . . . . . . . . . . . 25
   5.      IETF-SMING-SNMP-EXT  . . . . . . . . . . . . . . . . . . . 26
   6.      IETF-SMING-SNMP  . . . . . . . . . . . . . . . . . . . . . 33
   7.      Security Considerations  . . . . . . . . . . . . . . . . . 46
   8.      Acknowledgements . . . . . . . . . . . . . . . . . . . . . 46
           References . . . . . . . . . . . . . . . . . . . . . . . . 47
           Authors' Addresses . . . . . . . . . . . . . . . . . . . . 48
   A.      SMIng SNMP Mapping ABNF Grammar  . . . . . . . . . . . . . 48
   B.      OPEN ISSUES  . . . . . . . . . . . . . . . . . . . . . . . 53
           Full Copyright Statement . . . . . . . . . . . . . . . . . 55




















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1. Introduction

   This memo presents an SMIng language extension that supports 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
   definitions which are used to represent new SMIng base types such as
   floats in the SNMP protocol via the opaque mapping technique.

   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 data types and
   classes (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 [2].

2. SNMP Based Internet Management

   The SNMP network management framework [3] is based on the model of
   "managed objects".  A managed object represents a class of any real
   or synthesized variable of systems that are to be managed.  Note that
   in spite of these terms this model is not object-oriented.  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 an ordered list of non-negative numbers,
   named "sub-identifiers", where the left-most sub-identifier refers to
   the 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.  The number of sub-identifiers of an object
   identifier must not exceed 128.  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



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   done in a way 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.

   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.




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   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.

   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



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      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

   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



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      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.

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

3. SMIng Data Type Mappings

   SMIng [1] supports the following set of base types: OctetString,
   Identity, Integer32, Integer64, Unsigned32, Unsigned64, Float32,
   Float64, Float128, Enumeration, and Bits.  The SMIng core module
   IETF-SMING [1] defines additional derived data types, among them
   Counter32 (derived from Unsigned32), Counter64 (derived from
   Unsigned64), TimeTicks (derived from Unsigned32), IpAddress (derived
   from OctetString), and Opaque (derived from OctetString).




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   The version 2 of the protocol operations for SNMP document [16]
   defines the following 9 data types which are distinguished by the
   protocol: INTEGER, OCTET STRING, OBJECT IDENTIFIER, IpAddress,
   Counter32, TimeTicks, Opaque, Counter64, Unsigned32.

   The SMIng data 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)
           Identity           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

           Counter32          Counter32
           Counter64          Counter64
           TimeTicks          TimeTicks
           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
      type defined in [1].

   (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 TimeTicks SMIng
      type defined in [1].

   (4) This mapping includes all types derived from the Unsigned64 type
      except those types derived from the Counter64 SMIng type defined
      in [1].







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3.1 ASN.1 Definitions

   The ASN.1 [12] type definitions below introduce data types which are
   used to new SMIng base types into the set of ASN.1 types supported by
   the second version of SNMP protocol operations [16].


   IETF-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.  The floating point types Float32,
   Float64 and Float128 support single, double and quadruple 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 [13].

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 can 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.



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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 Identity.
   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 SMIng 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
   Identity can reference that identity.  The statement gets one
   argument which specifies the identity name.

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.







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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  IETF-SMING::null;
           status      current;
           description "A value used for null identifiers.";
       };

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
   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 SMIng 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.




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4.3.2 The scalars' implements Statement

   The scalars' `implements' statement, which must be present at least
   once, makes this scalar group contain scalar objects that are defined
   by a given class.  It gets two arguments: the class being implemented
   and a statement block that holds detailed information on the
   attributes of that class being implemented in an obligatory order.

   Note: It is possible to apply multiple implements statements to a
   single scalars statement, each specifying a distinct class.  However,
   it is considerable to define a new class containing thoses classes
   and making the scalar group implement that single container class.

4.3.2.1 The implements' object Statement

   The `object' statement, which must be present at least once, makes a
   single attribute of the class being contained as a scalar object in
   the scalar group.  It gets two arguments: the scalar object name and
   the class attribute being implemented.

   The object identifier of this scalar object is implicitly specified
   by concatenating the scalar group's object identifier and the
   position of the object, starting at 1.  [XXX see open issues: we
   better use mandatory explicit OID mapping.]

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
   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 groups SHOULD NOT be defined as `current' if one or more of
   their classes are `deprecated' or `obsolete'.  Similarly, they SHOULD
   NOT be defined as `deprecated' if one or more of their classes are
   `obsolete'.  Nevertheless, subsequent revisions of used class
   definition cannot be avoided, but SHOULD be taken into account in
   subsequent revisions of the local module.

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



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   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;
         implements      Ip {
           object        ipForwarding forwarding;
           object        ipDefaultTTL 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 SMIng grammar (Section 5) for
   the formal syntax of the `table' statement.

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



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   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)
   (see Section 4.4.4) and their order should be regarded as a hint for
   the index elements of the table.

   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.

4.4.2.2 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
   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.




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   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, except in another 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.

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 related 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 related tables may be used for multiple table
   expansions.

   Under some circumstances, an optional `implied' keyword may be added



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   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 implements Statement

   The table's `implements' statement, which must be present at least
   once, makes this table contain columnar objects that are defined by a
   given class.  It gets two arguments: the class being implemented and
   a statement block that holds detailed information on the attributes
   of that class being implemented in an obligatory order.

   Note: It is possible to apply multiple implements statements to a
   single table statement, each specifying a distinct class.  However,
   it is considerable to define a new class containing thoses classes
   and making the table implement that single container class.

4.4.4.1 The implements' object Statement

   The `object' statement, which must be present at least once, makes a
   single attribute of the class being contained as a columnar object in
   the table.  It gets two arguments: the columnar object name and the
   class attribute being implemented.

   The object identifier of this columnar object is implicitly specified
   by concatenating the table's object identifier, a single sub-
   identifier of the value 1 (in SMIv2 this represents the table entry
   definition) and the position of the object, starting at 1.  [XXX see
   open issues: we better use mandatory explicit OID mapping.]

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.

   Tables SHOULD NOT be defined as `current' if one or more of their
   classes are `deprecated' or `obsolete'.  Similarly, they SHOULD NOT



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   be defined as `deprecated' if one or more of their classes are
   `obsolete'.  Nevertheless, subsequent revisions of used class
   definition cannot be avoided, but SHOULD be taken into account in
   subsequent revisions of the local module.

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 scalar group.

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

4.5 The notification Statement

   The `notification' statement is used to map events of classes to SNMP
   notifications.  The 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 SMIng grammar (Section 5)
   for the formal syntax of the `notification' statement.





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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 argument: the event to be signaled (in the
   qualifed 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.

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,



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   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 SMIng grammar (Section 5) for
   the formal syntax of the `group' statement.

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.





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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 [14], may be described as
   follows:

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



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   See the `complianceStatement' rule of the SMIng 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.

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 the
   `mandatory' statement(s) of the compliance statement(s) of that
   module.





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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 module.  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 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 SMIng 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
   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 SMIng 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



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   object.  Type restrictions may be applied by appending subtyping
   information according to the rules of the base type.  See [1] 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 [1] 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.

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, converted to
   SMIng:








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       compliance snmpBasicCompliance {
         oid             snmpMIBCompliances.2;
         status          current;
         description
                 "The compliance statement for SNMPv2 entities which
                  implement the SNMPv2 MIB.";

         mandatory       (snmpGroup, snmpSetGroup, systemGroup,
                          snmpBasicNotificationsGroup);

         optional snmpCommunityGroup {
           description
                 "This group is mandatory for SNMPv2 entities which
                  support community-based authentication.";
         };
       };

5. IETF-SMING-SNMP-EXT

   The grammar of the SNMP mapping SMIng extension conforms to the
   Augmented Backus-Naur Form (ABNF) [11].  It is included in the abnf
   statement of the snmp SMIng extension definition in the IETF-SMING-
   SNMP-EXT module below.

   module IETF-SMING-SNMP-EXT {

       organization    "IETF Next Generation Structure of
                        Management Information Working Group (SMING)";

       contact         "Frank Strauss

                        TU Braunschweig
                        Bueltenweg 74/75
                        38106 Braunschweig
                        Germany

                        Phone: +49 531 391-3266
                        EMail: strauss@ibr.cs.tu-bs.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.";

       revision {
           date        "2001-03-02";



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           description "Initial revision, published as RFC &rfc.number;.";
       };

       //
       //
       //

       extension snmp {

           description
              "The snmp statement maps SMIng definitions to SNMP
               conformant definitions.";
           abnf "
   ;;
   ;; sming-snmp.abnf -- Grammar of SNMP mappings in ABNF
   ;;                    notation (RFC 2234).
   ;;
   ;; @(#) $Id: sming-snmp.abnf,v 1.8 2001/03/07 15:06:56 strauss Exp $
   ;;
   ;; Copyright (C) The Internet Society (2001). 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)
                                 *1(statusStatement stmtsep)
                                 descriptionStatement stmtsep
                                 *1(referenceStatement stmtsep)
                             '}' optsep ';'

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



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   representsStatement     = representsKeyword sep
                              qucIdentifier optsep ';'

   scalarsStatement        = scalarsKeyword sep lcIdentifier optsep
                                 '{' stmtsep
                                 oidStatement stmtsep
                              1*(implementsStatement stmtsep)
                                 *1(statusStatement stmtsep)
                                 descriptionStatement stmtsep
                                 *1(referenceStatement stmtsep)
                             '}' optsep ';'

   tableStatement          = tableKeyword sep lcIdentifier optsep
                                 '{' stmtsep
                                 oidStatement stmtsep
                                 anyIndexStatement stmtsep
                                 *1(createStatement stmtsep)
                              1*(implementsStatement stmtsep)
                                 *1(statusStatement stmtsep)
                                 descriptionStatement stmtsep
                                 *1(referenceStatement stmtsep)
                             '}' optsep ';'

   implementsStatement     = implementsKeyword sep qucIdentifier optsep
                                 '{' stmtsep
                                 1*(implObjectStatement stmtsep)
                             '}' optsep ';'

   implObjectStatement     = objectKeyword sep
                              lcIdentifier sep
                              attrIdentifier optsep;

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

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

   signalsObjectStatement  = objectKeyword sep
                              qattrIdentifier optsep ';'



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

   complianceStatement     = complianceKeyword sep lcIdentifier optsep
                                 '{' stmtsep
                                 oidStatement stmtsep
                                 *1(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 ';'



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   membersStatement        = membersKeyword optsep '(' optsep
                                 qlcIdentifierList optsep
                                 ')' optsep ';'

   mandatoryStatement      = mandatoryKeyword optsep '(' optsep
                                 qlcIdentifierList optsep
                                 ')' optsep ';'

   optionalStatement       = optionalKeyword sep qlcIdentifier optsep
                                 '{' descriptionStatement stmtsep
                             '}' 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 ';'

   ;;
   ;;
   ;;

   objectIdentifier        = (qlcIdentifier / subid) *127('.' subid)

   subid                   = decimalNumber

   ;;
   ;; 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



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                          %x73
   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
   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

   ;;
   ;; EOF
   ;;
                 ";
       };

       extension agentcaps {
           status      current;
           description
                 "The agentcaps extension statement is used to describe
                  an SNMP agent's deviation from the compliance statements
                  of the modules it implements. It is designed to be
                  compatible with the SMIv2 AGENT-CAPABILITIES macro.

                  The agentcaps extension statement should only be used
                  in the snmp statement body of a module that does not
                  contain any other definitions that do not
                  correspond to an agent implementation.";
           abnf
                 "
   ;;
   ;;
   ;;

   agentcapsStatement = 'agentcaps' sep lcIdentifier
                        optsep '{' stmtsep



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                          oidStatement stmtsep
                          releaseStatement stmtsep
                          *1(statusStatement stmtsep)
                          descriptionStatement stmtsep
                          *1(referenceStatement stmtsep)
                          *(includesStatement stmtsep)
                        '}' optsep ';'

   includesStatement  = 'includes' sep qlcIdentifier
                        optsep '{' stmtsep
                          *(variationStatement stmtsep)
                        '}' optsep ';'

   variationStatement = 'variation' sep qlcIdentifier
                        optsep '{' stmtsep
                          typeStatement stmtsep
                          writetypeStatement stmtsep
                          accessStatement stmtsep
                          createStatement stmtsep
                        '}' optsep ';'

   ;;
   ;;
   ;;
                  ";
       };

       //
       //
       //

       typedef ObjectIdentifier {
           type            Pointer;
           description
              "";
       };

       //
       //
       //

       snmp {

           node ccitt                       { oid 0;          };

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



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           };

           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;          };

       };

   };


6. IETF-SMING-SNMP

   module IETF-SMING-SNMP {

       organization    "IETF Next Generation Structure of
                        Management Information Working Group (SMING)";

       contact         "Frank Strauss

                        TU Braunschweig
                        Bueltenweg 74/75
                        38106 Braunschweig
                        Germany

                        Phone: +49 531 391-3266
                        EMail: strauss@ibr.cs.tu-bs.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.";




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       revision {
           date        "2001-01-04";
           description "Initial version, published as RFC &rfc.number;.";
       };

       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 syntax 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 syntax is either `read-write' or `read-create'.
                When an instance of a columnar object having this syntax
                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 syntax 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;



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

       typedef RowPointer {
           type        Pointer;
           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 textual convention is used to manage the
            creation and deletion of conceptual rows, and is used as the
            value of the SYNTAX clause for the status column of a
            conceptual row (as described in Section 7.7.1 of [2].)

            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



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                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.

            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.




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            To summarize the effect of having a conceptual row with a
            status column having a SYNTAX clause value of RowStatus,
            consider the following state diagram:

                                            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) goto B or C, depending on information available to the


            agent.




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            (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.

            (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.




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

                             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.



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            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
            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



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                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.

            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



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                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
                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.





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                - 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,
                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



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                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
                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



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            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.";
       };

       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 1906."
       };

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



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                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
                MIB modules.

                A zero-length TAddress value denotes an unknown transport
                service address."
           reference
               "The SNMPv2-TM MIB module is defined in RFC 1906."
       };

       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
   langauge which support 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 [5],
   [6], [7] 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, and Bert Wijnen.

   Marshall T.  Rose's work on an XML framework for RFC authors [15]
   made the writing of an Internet standards document much more



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   comfortable.

References

   [1]   Strauss, F. and J. Schoenwaelder, "SMIng - Next Generation
         Structure of Management Information", draft-ietf-sming-02.txt,
         July 2001.

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

   [3]   Case, J., Mundy, R., Partain, D. and B. Stewart, "Introduction
         to Version 3 of the  Internet-standard Network Management
         Framework", RFC 2570, April 1999.

   [4]   Harrington, D., Presuhn, R. and B. Wijnen, "An Architecture for
         Describing SNMP Management Frameworks", RFC 2571, April 1999.

   [5]   McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose,
         M. and S. Waldbusser, "Structure of Management Information
         Version 2 (SMIv2)", RFC 2578, STD 58, April 1999.

   [6]   McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose,
         M. and S. Waldbusser, "Textual Conventions for SMIv2", RFC
         2579, STD 59, April 1999.

   [7]   McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J., Rose,
         M. and S. Waldbusser, "Conformance Statements for SMIv2", RFC
         2580, STD 60, April 1999.

   [8]   Rose, M. and K. McCloghrie, "Structure and Identification of
         Management Information for TCP/IP-based Internets", RFC 1155,
         STD 16, May 1990.

   [9]   Rose, M. and K. McCloghrie, "Concise MIB Definitions", RFC
         1212, STD 16, March 1991.

   [10]  Rose, M., "A Convention for Defining Traps for use with the
         SNMP", RFC 1215, March 1991.

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

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

   [13]  Institute of Electrical and Electronics Engineers, "IEEE



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         Standard for Binary Floating-Point Arithmetic", ANSI/IEEE
         Standard 754-1985, August 1985.

   [14]  Case, J., McCloghrie, K., Rose, M. and S. Waldbusser,
         "Management Information Base for Version 2 of the Simple
         Network Management Protocol (SNMPv2)", RFC 1907, January 1996.

   [15]  Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629, June
         1999.

   [16]  Presuhn, R., Case, J., McCloghrie, K., Rose, M. and S.
         Waldbusser, "Version 2 of the Protocol Operations for the
         Simple  Network Management Protocol", draft-ietf-snmpv3-update-
         proto-06.txt, July 2001.


Authors' Addresses

   Frank Strauss
   TU Braunschweig
   Bueltenweg 74/75
   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
   TU Braunschweig
   Bueltenweg 74/75
   38106 Braunschweig
   Germany

   Phone: +49 531 391-3289
   EMail: schoenw@ibr.cs.tu-bs.de
   URI:   http://www.ibr.cs.tu-bs.de/

Appendix A. SMIng SNMP Mapping ABNF Grammar

    The grammar of the SMIng SNMP mapping conforms to the Augmented
   Backus-Naur Form (ABNF) [11].

   ;;
   ;; sming-snmp.abnf -- Grammar of SNMP mappings in ABNF
   ;;                    notation (RFC 2234).
   ;;



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   ;; @(#) $Id: sming-snmp.abnf,v 1.9 2001/07/20 14:13:10 strauss Exp $
   ;;
   ;; Copyright (C) The Internet Society (2001). 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*(implementsStatement stmtsep)
                                 statusStatement stmtsep
                                 descriptionStatement stmtsep
                                 *1(referenceStatement stmtsep)
                             "}" optsep ";"

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



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                                 *1(createStatement stmtsep)
                              1*(implementsStatement stmtsep)
                                 statusStatement stmtsep
                                 descriptionStatement stmtsep
                                 *1(referenceStatement stmtsep)
                             "}" optsep ";"

   implementsStatement     = implementsKeyword sep qucIdentifier optsep
                                 "{" stmtsep
                                 1*(implObjectStatement stmtsep)
                             "}" optsep ";"

   implObjectStatement     = objectKeyword sep
                              lcIdentifier sep
                              attrIdentifier 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
                                 oidStatement stmtsep
                                 statusStatement stmtsep
                                 descriptionStatement stmtsep
                                 *1(referenceStatement stmtsep)



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                                 *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
                             "}" optsep ";"

   refineStatement         = refineKeyword sep qlcIdentifier optsep "{"
                                 *1(typeStatement stmtsep)



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                                 *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 ";"

   ;;
   ;;
   ;;

   objectIdentifier        = (qlcIdentifier / subid) *127("." subid)

   subid                   = decimalNumber

   ;;
   ;; 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
   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



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   expandsKeyword      =  %x65 %x78 %x70 %x61 %x6E %x64 %x73
   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

   ;;
   ;; EOF
   ;;


Appendix B. OPEN ISSUES

   Pointers -  We don't know how to express assiciations/relations to
      class instances or attribute instances.  If we should define a
      `Pointer' base type, it would probably be mapped to OIDs.  One can
      argue to generalize the concept of pointers so that they can be
      used to model relationships that are not necessarily realized by
      OID pointers.

   Associations -  In general, the modeling of associations between
      instances may need better supported at the SMIng data definition
      level so that SNMP table interrelationships just map these
      instance-level associations.

   Mapping to SNMPv1 -  The data type mapping is currently only defined
      for SNMPv2c and SNMPv3.  A straight-forward extension is possible
      to also support SNMPv1.

   Conversion SMIng -> SMIv2 -  It may be useful to define the
      conversion from SMIng to SMIv2.

   Conversion SMIv2 -> SMIng -  It may be useful to define the
      conversion from SMIv2 to SMIng.

   Revision of IETF-SMING-SNMP -  The IETF-SMING-SNMP needs a serious
      review to see which wordings must be adapted to the new
      terminology.  Perhaps some new classes should be added (such as a
      grouping of RowStatus and StorageType).

   Document Structure -  There are some parts in this document which
      will also be needed by the COPS-PR mapping.  Does it make sense to
      separate them out?

   SNMP access Statement -  There must be an SNMP access statement which
      provides the semantics known from SMIv2.



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   Implicit Entry Definitions -  Is it ok to have table row nodes
      (Entries) implicitly defined (e.g., naming conventions)?

   Order of `object' arguments -  The order of the arguments in the
      objects statement is not intuitive.

   `implements' keyword -  The `implements' statement is confusing -
      need a better keyword name.

   Implicit OID Assignments considered harmful -  Implicit OID
      assignments are a potential source of problems.  It might be
      better to explicitly assign OIDs.

   SNMP Mapping Identifiers -  What's the scope of identifiers defined
      by SNMP mapping? Do we need to import such identifiers in SNMP
      mapping modules?

   `extends' vs.  `expands' -  These two keyword seem to be confusing?
      Any proposals?

   Special Table Relationships -  Dave Perkins noted that RMON2 has a
      table relationship which is not covered by what we have.





























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Full Copyright Statement

   Copyright (C) The Internet Society (2001).  All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works.  However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assigns.

   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgement

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



















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