module EXPRESSION-MIB {

    yang-version 1;

    namespace
      "urn:ietf:params:xml:ns:yang:smiv2:EXPRESSION-MIB";

    prefix EXPRESSION-MIB;

    import SNMPv2-TC {
      prefix snmpv2-tc;
    }
    import ietf-inet-types {
      prefix inet;
    }
    import ietf-yang-smiv2 {
      prefix smiv2;
    }
    import ietf-yang-types {
      prefix yang;
    }

    organization
      "IETF Distributed Management Working Group";

    contact
      "       Cisco Systems
    Customer Service
    
    Postal: 170 W Tasman Drive
    San Jose, CA  95134
    USA
    
    Tel: +1 800 553-NETS
    
    E-mail: cs-snmp@cisco.com";

    description
      "The MIB module for defining expressions of MIB objects
    for network management purposes.
    
    This MIB is an early snapshot of work done by the IETF's
    Distributed Management working group.  After this snapshot
    was taken, the MIB was modified, had new OIDs assigned,
    and then published as RFC 2982.";

    revision "2005-11-24" {
      description
        "Imported Unsigned32 from SNMPv2-SMI.";
    }

    revision "1998-02-25" {
      description
        "Initial version of the mib module.";
    }

    smiv2:alias "sysUpTimeInstance" {
      smiv2:oid "1.3.6.1.2.1.1.3.0";
    }
    smiv2:alias "expressionMIB" {
      smiv2:oid "1.3.6.1.4.1.9.10.22";
    }
    smiv2:alias "expressionMIBObjects" {
      smiv2:oid "1.3.6.1.4.1.9.10.22.1";
    }
    smiv2:alias "expResource" {
      smiv2:oid "1.3.6.1.4.1.9.10.22.1.1";
    }
    smiv2:alias "expNames" {
      smiv2:oid "1.3.6.1.4.1.9.10.22.1.2";
    }
    smiv2:alias "expDefine" {
      smiv2:oid "1.3.6.1.4.1.9.10.22.1.3";
    }
    smiv2:alias "expValue" {
      smiv2:oid "1.3.6.1.4.1.9.10.22.1.4";
    }
    smiv2:alias "expressionMIBConformance" {
      smiv2:oid "1.3.6.1.4.1.9.10.22.3";
    }
    smiv2:alias "expressionMIBCompliances" {
      smiv2:oid "1.3.6.1.4.1.9.10.22.3.1";
    }
    smiv2:alias "expressionMIBGroups" {
      smiv2:oid "1.3.6.1.4.1.9.10.22.3.2";
    }

    typedef ExpressionName {
      type binary {
        length "1..64";
      }
      description
        "This data type is a refinement of DisplayString to
      represent an identification for an expression.  An
      ExpressionName corresponds one-to-one to an
      ExpressionIndex.
      
      This identification of an expression is subject to change
      only by administrative request.";
    }

    typedef ExpressionIndex {
      type uint32 {
        range "1..4294967295";
      }
      description
        "An integer shorthand identification for an expression.
      An ExpressionIndex corresponds one-to-one to an
      ExpressionName.
      
      Once assigned an ExpressionIndex may not be changed.";
    }

    typedef ExpressionIndexOrZero {
      type uint32 {
        range "0..4294967295";
      }
      description
        "Either an ExpressionIndex or zero.  The meaning of zero
      depends on the DESCRIPTION of the object.";
    }

    container EXPRESSION-MIB {
      config false;
      container expResource {
        smiv2:oid "1.3.6.1.4.1.9.10.22.1.1";
        leaf expResourceDeltaMinimum {
          smiv2:max-access "read-write";
          smiv2:oid "1.3.6.1.4.1.9.10.22.1.1.1";
          type int32 {
            range "-1|1..600";
          }
          units "seconds";
          description
            "The minimum expExpressionDeltaInterval this system will
          accept.  A system may use the larger values of this minimum
          to lessen the impact of constantly computing deltas.
          
          The value -1 indicates this system will not accept
          deltaValue as a value for expObjectSampleType.
          
          Unless explicitly resource limited, a system's value for
          this object should be 1.
          
          Changing this value will not invalidate an existing setting
          of expObjectSampleType.";
        }

        leaf expResourceDeltaWildcardInstanceMaximum {
          smiv2:max-access "read-write";
          smiv2:oid "1.3.6.1.4.1.9.10.22.1.1.2";
          type uint32;
          units "instances";
          description
            "The maximum number of dynamic instance entries this system
          will support for wildcarded delta objects in expressions.
          These are the entries that maintain state, one for each
          instance of each deltaValue object for each value of an
          expression.
          
          A value of 0 indicates no preset limit, that is, the limit
          is dynamic based on system operation and resources.
          
          Unless explicitly resource limited, a system's value for
          this object should be 0.
          
          Changing this value will not eliminate or inhibit existing
          delta wildcard instance objects but will prevent the
          creation of more such objects.";
        }

        leaf expResourceDeltaWildcardInstances {
          smiv2:max-access "read-only";
          smiv2:oid "1.3.6.1.4.1.9.10.22.1.1.3";
          type yang:gauge32;
          units "instances";
          description
            "The number of currently active instance entries as
          defined for expResourceDeltaWildcardInstanceMaximum.";
        }

        leaf expResourceDeltaWildcardInstancesHigh {
          smiv2:max-access "read-only";
          smiv2:oid "1.3.6.1.4.1.9.10.22.1.1.4";
          type yang:gauge32;
          units "instances";
          description
            "The highest value of expResourceDeltaWildcardInstances
          that has occurred since initialization of the management
          system.";
        }

        leaf expResourceDeltaWildcardInstanceResourceLacks {
          smiv2:max-access "read-only";
          smiv2:oid "1.3.6.1.4.1.9.10.22.1.1.5";
          type yang:counter32;
          units "instances";
          description
            "The number of times this system could not evaluate an
          expression because that would have created a value
          instance in excess of
          expResourceDeltaWildcardInstanceMaximum.";
        }
      }  // container expResource

      container expNames {
        smiv2:oid "1.3.6.1.4.1.9.10.22.1.2";
        leaf expNameLastChange {
          smiv2:max-access "read-only";
          smiv2:oid "1.3.6.1.4.1.9.10.22.1.2.1";
          type yang:timestamp;
          description
            "The value of sysUpTime the last time an expression was
          created or deleted or had its name changed using
          expExpressionName.";
        }

        leaf expNameHighestIndex {
          smiv2:max-access "read-only";
          smiv2:oid "1.3.6.1.4.1.9.10.22.1.2.2";
          type ExpressionIndexOrZero;
          description
            "The highest value of ExpressionIndex ever assigned on
          this system.  Preferrably this value is preserved across
          system reboots.  A managed system that is unable to
          store expressions across reboots need not preserve this
          value across reboots.
          
          If all expression-creating applications cooperate, they
          may use this to avoid reusing an ExpressionIndex.  To
          do so, attempt creation of a new entry with this
          value + 1 as the value of expExpressionIndex.
          
          Although reusing ExpressionIndexes could lead to an
          application receiving a misunderstood value, it is a
          matter of local management policy whether to reuse them.";
        }
      }  // container expNames

      container expNameTable {
        smiv2:oid "1.3.6.1.4.1.9.10.22.1.2.3";
        description
          "A table of expression names, for creating and deleting
        expressions.";
        list expNameEntry {
          smiv2:oid "1.3.6.1.4.1.9.10.22.1.2.3.1";
          key "expName";
          description
            "Information about a single expression.  New expressions
          can be created using expNameStatus.
          
          To create an expression first create the named entry in this
          table.  Then use expExpressionIndex to populate
          expExpressionTable and expObjectTable.  For expression
          evaluation to succeed all related entries in expNameTable,
          expExpressionTable, and expObjectTable must be 'active'.  If
          these conditions are not met the corresponding values in
          expValue simply are not instantiated.
          
          Deleting an entry deletes all related entries in
          expExpressionTable and expObjectTable.
          
          Because of the relationships among the multiple tables
          for an expression (expNameTable, expExpressionTable,
          expObjectTable, and expValueTable) and the SNMP rules
          for independence in setting object values, it is
          necessary to do final error checking when an expression
          is evaluated, that is, when one of its instances in
          expValueTable is read.  Earlier checking need not be
          done and an implementation may not impose any ordering
          on the creation of objects related to an expression other
          than to require values for expName and expExpressionIndex
          before any other related objects can be created.
          
          To maintain security of MIB information, when creating a new
          row in this table, the managed system must record the
          security credentials of the requester.  If the subsequent
          expression includes objects with expObjectSampleType
          'deltaValue' the evaluation of that expression takes place
          under the security credentials of the creator of its
          expNameEntry.";
          leaf expName {
            smiv2:max-access "not-accessible";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.2.3.1.1";
            type ExpressionName;
            description
              "The name of the expression.  Choosing names with useful
            lexical ordering supports using GetNext or GetBulk to
            retrieve a useful subset of the table.";
          }

          leaf expExpressionIndex {
            smiv2:max-access "read-write";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.2.3.1.2";
            type ExpressionIndex;
            description
              "The numeric identification of the expression.
            
            Applications may select this number in ascending numerical
            order by using expNameHighestIndex as a hint or may use any
            other acceptable, unused number.
            
            Once set this value may not be set to a different value.";
          }

          leaf expNameStatus {
            smiv2:max-access "read-write";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.2.3.1.3";
            type snmpv2-tc:RowStatus;
            description
              "The control that allows creation/deletion of entries.";
          }
        }  // list expNameEntry
      }  // container expNameTable

      container expExpressionTable {
        smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.1";
        description
          "A table of expression definitions.";
        list expExpressionEntry {
          smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.1.1";
          key "expExpressionIndex";
          description
            "Information about a single expression.  An entry appears
          in this table when an entry is created in expNameTable.
          Deleting that expNameTable entry automatically deletes
          this entry and its associated expObjectTable entries.
          
          Values of read-write objects in this table may be changed
          at any time.";
          leaf expExpressionIndex {
            type leafref {
              path "/EXPRESSION-MIB:EXPRESSION-MIB/EXPRESSION-MIB:expNameTable/EXPRESSION-MIB:expNameEntry/EXPRESSION-MIB:expExpressionIndex";
            }
          }

          leaf expExpressionName {
            smiv2:max-access "read-write";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.1.1.1";
            type ExpressionName;
            description
              "The unique name of the expression, the same as expName.
            
            Use this object to change the expression's name without
            changing its expExpressionIndex.";
          }

          leaf expExpression {
            smiv2:max-access "read-write";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.1.1.2";
            type binary {
              length "1..1024";
            }
            description
              "The expression to be evaluated.  This object is the same
            as a DisplayString (RFC 1903) except for its maximum length.
            
            Except for the variable names the expression is in ANSI C
            syntax.  Only the subset of ANSI C operators and functions
            listed here is allowed.
            
            Variables are expressed as a dollar sign ('$') and an
            integer that corresponds to an expObjectIndex.  An
            example of a valid expression is:
            
                    ($1-$5)*100
            
            Expressions may not be recursive, that is although an
            expression may use the results of another expression, it
            may not contain any variable that is directly or
            indirectly a result of its own evaluation.
            
            The only allowed operators are:
            
                    ( )
                    - (unary)
                    + - * / %
                    & | ^ << >> ~
                    ! && || == != > >= < <=
            
            Note the parentheses are included for parenthesizing the
            expression, not for casting data types.
            
            The only constant types defined are:
            
                    int (32-bit signed)
                    long (64-bit signed)
                    unsigned int
                    unsigned long
                    hexadecimal
                    character
                    string
                    oid
            
            The default type for a positive integer is int unless it
            is too large in which case it is long.
            
            All but oid are as defined for ANSI C.  Note that a
            hexadecimal constant may end up as a scalar or an array of
            8-bit integers.  A string constant is enclosed in double
            quotes and may contain back-slashed individual characters
            as in ANSI C.
            
            An oid constant comprises 32-bit, unsigned integers and at
            least one period, for example:
            
                    0.
                    .0
                    1.3.6.1
            
            Integer-typed objects are treated as 32- or 64-bit, signed
            or unsigned integers, as appropriate.  The results of
            mixing them are as for ANSI C, including the type of the
            result.  Note that a 32-bit value is thus promoted to 64
            bits only in an operation with a 64-bit value.  There is
            no provision for larger values to handle overflow.
            
            Relative to SNMP data types, a resulting value becomes
            unsigned when calculating it uses any unsigned value,
            including a counter.  To force the final value to be of
            data type counter the expression must explicitly use the
            counter32() or counter64() function (defined below).
            
            OCTET STRINGS and OBJECT IDENTIFIERs are treated as 1-based
            arrays of unsigned 8-bit integers and unsigned 32-bit
            integers, respectively.
            
            IpAddresses are treated as 32-bit, unsigned integers in
            network byte order, that is, the hex version of 255.0.0.0 is
            0xff000000.
            
            Conditional expressions result in a 32-bit, unsigned integer
            of value 0 for false or 1 for true. When an arbitrary value
            is used as a boolean 0 is false and non-zero is true.
            
            Rules for the resulting data type from an operation, based
            on the operator:
            
            For << and >> the result is the same as the left hand
            operand.
            
            For &&, ||, ==, !=, <, <=, >, and >= the result is always
            Unsigned32.
            
            For unary - the result is always Integer32.
            
            For +, -, *, /, %, &, |, and ^ the result is promoted
            according to the following rules, in order from most to
            least preferred:
            
                    If left hand and right hand operands are the same
                    type, use that.
            
                    If either side is Counter64, use that.
            
                    If either side is IpAddress, use that.
            
                    If either side is TimeTicks, use that.
            
                    If either side is Counter32, use that.
            
                    Otherwise use Unsigned32.
            
            The following rules say what operators apply with what
            data types.  Any combination not explicitly defined does
            not work.
            
            For all operators any of the following can be the left
            hand or right hand operand: Integer32, Counter32,
            Unsigned32, Counter64.
            
            The operators +, -, *, /, %, <, <=, >, and >= also work with
            TimeTicks.
            
            The operators &, |, and ^ also work with IpAddress.
            
            The operators << and >> also work with IpAddress but only
            as the left hand operand.
            
            The + operator performs a concatenation of two OCTET STRINGs
            or two OBJECT IDENTIFIERs.
            
            The operators &, | perform bitwise operations on
            OCTET STRINGs.  If the OCTET STRING happens to be a
            DisplayString the results may be meaningless, but the agent
            system does not check this as some such systems do not
            have this information.
            
            The operators << and >> perform bitwise operations on
            OCTET STRINGs appearing as the left hand operand.
            
            The only functions defined are:
            
                    counter32
                    counter64
                    arraySection
                    stringBegins
                    stringEnds
                    stringContains
                    oidBegins
                    oidEnds
                    oidContains
                    sum
                    exists
            
            The following function definitions indicate their by naming
            the data type of the parameter in the parameter's position
            in the parameter list.  The parameter must be of the type
            indicated and generally may be a constant, a MIB object, a
            function, or an expression.
            
            counter32(integer) - wrapped around an integer value
            counter32 forces Counter32 as a data type.
            
            counter64(integer) - similar to counter32 except that the
            resulting data type is 'counter64'.
            
            arraySection(array, integer, integer) - selects a piece of
            an array (i.e. part of an OCTET STRING or
            OBJECT IDENTIFIER).  The integer arguments are in the
            range 0 to 4,294,967,295.  The first is an initial array
            index (1-based) and the second is an ending array index. 
            A value of 0 indicates first or last element, respectively. 
            If the first element is larger than the array length the
            result is 0 length.  If the second integer is less than or
            equal to the first, the result is 0 length.  If the second
            is larger than the array length it indicates last element.
            
            stringBegins/Ends/Contains(octetString, octetString) -
            looks for the second string (which can be a string constant)
            in the first and returns the 1-based index where the match
            began.  A return value of 0 indicates no match (i.e.
            boolean false).
            
            oidBegins/Ends/Contains(oid, oid) - looks for the second OID
            (which can be an OID constant) in the first and returns the
            the 1-based index where the match began.  A return value
            of 0 indicates no match (i.e. boolean false).
            
            sum(integerObject*) - sums all availiable values of the
            wildcarded integer object, resulting in an integer scalar.
            Must be used with caution as it wraps on overflow with no
            notification.
            
            exists(anyTypeObject) - verifies the object instance
            exists. A return value of 0 indicates NoSuchInstance
            (i.e. boolean false).";
          }

          leaf expExpressionValueType {
            smiv2:defval "counter32";
            smiv2:max-access "read-write";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.1.1.3";
            type enumeration {
              enum "counter32" {
                value 1;
              }
              enum "unsignedOrGauge32" {
                value 2;
              }
              enum "timeTicks" {
                value 3;
              }
              enum "integer32" {
                value 4;
              }
              enum "ipAddress" {
                value 5;
              }
              enum "octetString" {
                value 6;
              }
              enum "objectId" {
                value 7;
              }
              enum "counter64" {
                value 8;
              }
            }
            description
              "The type of the expression value.  One and only one of
            the value objects in expValueTable will be instantiated to
            match this type.
            
            If the result of the expression can not be made into this
            type, an invalidOperandType error will occur.";
          }

          leaf expExpressionComment {
            smiv2:defval "";
            smiv2:max-access "read-write";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.1.1.4";
            type snmpv2-tc:DisplayString;
            description
              "A comment to explain the use or meaning of the expression.";
          }

          leaf expExpressionDeltaInterval {
            smiv2:defval "0";
            smiv2:max-access "read-write";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.1.1.5";
            type int32 {
              range "0..86400";
            }
            units "seconds";
            description
              "Sampling interval for objects in this expression with
            expObjectSampleType 'deltaValue'.
            
            This object is not instantiated if not applicable.
            
            A value of 0 indicates no automated sampling.  In this case
            the delta is the difference from the last time the
            expression was evaluated.  Note that this is subject to
            unpredictable delta times in the face of retries or
            multiple managers.
            
            A value greater than zero is the number of seconds between
            automated samples.
            
            Until the delta interval has expired once the delta for the
            object is effectively not instantiated and evaluating
            the expression has results as if the object itself were not
            instantiated.
            
            Note that delta values potentially consume large amounts of
            system CPU and memory.  Delta state and processing must
            continue constantly even if the expression is not being
            used.  That is, the expression is being evaluated every
            delta interval, even if no application is reading those
            values.  For wildcarded objects this can be substantial
            overhead.
            
            Note that delta intervals, external expression value
            sampling intervals and delta intervals for expressions
            within other expressions can have unusual interactions as
            they are impossible to synchronize accurately.  In general
            one interval embedded below another must be enough shorter
            that the higher sample sees relatively smooth, predictable
            behavior.";
          }

          leaf expExpressionPrefix {
            smiv2:max-access "read-only";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.1.1.6";
            type yang:object-identifier-128;
            description
              "An object prefix to assist an application in determining
            the instance indexing to use in expValueTable, relieving the
            application of the need to scan the expObjectTable to
            determine such a prefix.
            
            See expObjectTable for information on wildcarded objects.
            
            If the expValueInstance portion of the value OID may
            be treated as a scalar (that is, normally, 0) the value of
            expExpressionPrefix is zero length, that is, no OID at all.
            
            Otherwise expExpressionPrefix is the value of any wildcarded
            instance of expObjectID for the expression.  This is
            sufficient as the remainder, that is, the instance fragment
            relevant to instancing the values must be the same for all
            wildcarded objects in the expression.";
          }

          leaf expExpressionErrors {
            smiv2:max-access "read-only";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.1.1.7";
            type yang:counter32;
            description
              "The number of errors encountered while evaluating this
            expression.
            
            Note that an object in the expression not being accessible
            is not considered an error.  It is a legitimate condition
            that causes the corresponding expression value not to be
            instantiated.";
          }

          leaf expExpressionErrorTime {
            smiv2:max-access "read-only";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.1.1.8";
            type yang:timestamp;
            description
              "The value of sysUpTime the last time an error caused a
            failure to evaluate this expression.
            
            This object is not instantiated if there have been no
            errors.";
          }

          leaf expExpressionErrorIndex {
            smiv2:max-access "read-only";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.1.1.9";
            type int32;
            description
              "The 1-based character index into expExpression for where
            the error occurred.  The value zero indicates irrelevance.
            
            This object is not instantiated if there have been no
            errors.";
          }

          leaf expExpressionError {
            smiv2:max-access "read-only";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.1.1.10";
            type enumeration {
              enum "invalidSyntax" {
                value 1;
              }
              enum "undefinedObjectIndex" {
                value 2;
              }
              enum "unrecognizedOperator" {
                value 3;
              }
              enum "unrecognizedFunction" {
                value 4;
              }
              enum "invalidOperandType" {
                value 5;
              }
              enum "unmatchedParenthesis" {
                value 6;
              }
              enum "tooManyWildcardValues" {
                value 7;
              }
              enum "recursion" {
                value 8;
              }
              enum "deltaTooShort" {
                value 9;
              }
              enum "resourceUnavailable" {
                value 10;
              }
              enum "divideByZero" {
                value 11;
              }
            }
            description
              "The error that occurred.  In the following explanations the
            expected timing of the error is in parentheses.  'S' means
            the error occurs on a Set request.  'E' means the error
            occurs on the attempt to evaluate the expression either
            due to Get from expValueTable or in ongoing delta
            processing.
            
            invalidSyntax           the value sent for expExpression
                                    is not valid Expression MIB
                                    expression syntax (S)
            undefinedObjectIndex    an object reference ($n) in
                                    expExpression does not have a
                                    matching instance in
                                    expObjectTable (E)
            unrecognizedOperator    the value sent for expExpression
                                    held an unrecognized operator (S)
            unrecognizedFunction    the value sent for expExpression
                                    held an unrecognized function
                                    name (S)
            invalidOperandType      an operand in expExpression is not
                                    the right type for the associated
                                    operator or result (SE)
            unmatchedParenthesis    the value sent for expExpression
                                    is not correctly parenthesized (S)
            tooManyWildcardValues   evaluating the expression exceeded
                                    the limit set by expResourceDelta
                                    WildcardInstanceMaximum (E)
            recursion               through some chain of embedded
                                    expressions the expression invokes
                                    itself (E)
            deltaTooShort           the delta for the next evaluation
                                    passed before the system could
                                    evaluate the present sample (E)
            resourceUnavailable     some resource, typically dynamic
                                    memory, was unavailable (SE)
            divideByZero            an attempt to divide by zero
                                    occurred (E)
            
            For the errors that occur when the attempt is made to set
            expExpression Set request fails with the SNMP error code
            'wrongValue'. Such failures refer to the most recent failure
            to Set expExpression, not to the present value of
            expExpression which must be either unset or syntactically
            correct.
            
            Errors that occur during evalutaion for a Get* operation
            return the SNMP error code 'genErr' except for
            'tooManyWildcardValues' and 'resourceUnavailable' which
            return the SNMP error code 'resourceUnavailable'.
            
            This object is not instantiated if there have been no
            errors.";
          }

          leaf expExpressionInstance {
            smiv2:max-access "read-only";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.1.1.11";
            type yang:object-identifier-128;
            description
              "The expValueInstance being evaluated when the error
            occurred.  A zero-length indicates irrelevance.
            
            This object is not instantiated if there have been no
            errors.";
          }

          leaf expExpressionOwner {
            smiv2:defval "";
            smiv2:max-access "read-write";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.1.1.12";
            type snmpv2-tc:DisplayString {
              length "0..255";
            }
            description
              "The entity that configured this entry and is therefore
            using the resources assigned to it.";
          }
        }  // list expExpressionEntry
      }  // container expExpressionTable

      container expObjectTable {
        smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.2";
        description
          "A table of object definitions for each expExpression.
        
        Wildcarding instance IDs:
        
        It is legal to omit all or part of the instance portion for
        some or all of the objects in an expression. (See the
        DESCRIPTION of expObjectID for details.  However, note that
        if more than one object in the same expression is wildcarded
        in this way, they all must be objects where that portion of
        the instance is the same.  In other words, all objects may
        be in the same SEQUENCE or in different SEQUENCEs but with
        the same semantic index value (e.g., a value of ifIndex)
        for the wildcarded portion.";
        list expObjectEntry {
          smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.2.1";
          key "expExpressionIndex expObjectIndex";
          description
            "Information about an object.  An application uses
          expObjectStatus to create entries in this table while
          in the process of defining an expression.
          
          Values of read-create objects in this table may be
          changed at any time.";
          leaf expExpressionIndex {
            type leafref {
              path "/EXPRESSION-MIB:EXPRESSION-MIB/EXPRESSION-MIB:expNameTable/EXPRESSION-MIB:expNameEntry/EXPRESSION-MIB:expExpressionIndex";
            }
          }

          leaf expObjectIndex {
            smiv2:max-access "not-accessible";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.2.1.1";
            type uint32 {
              range "1..4294967295";
            }
            description
              "Within an expression, a unique, numeric identification
            for an object.  Prefixed with a dollar sign ('$') this is
            used to reference the object in the corresponding
            expExpression.";
          }

          leaf expObjectID {
            smiv2:max-access "read-write";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.2.1.2";
            type yang:object-identifier-128;
            description
              "The OBJECT IDENTIFIER (OID) of this object.  The OID may be
            fully qualified, meaning it includes a complete instance
            identifier part (e.g., ifInOctets.1 or sysUpTime.0), or it
            may not be fully qualified, meaning it may lack all or part
            of the instance identifier.  If the expObjectID is not fully
            qualified, then expObjectWildcard must be set to true(1).  
            The value of the expression will be multiple
            values, as if done for a GetNext sweep of the object.
            
            An object here may itself be the result of an expression but
            recursion is not allowed.
            
            NOTE:  The simplest implementations of this MIB may not
            allow wildcards.";
          }

          leaf expObjectIDWildcard {
            smiv2:defval "false";
            smiv2:max-access "read-write";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.2.1.3";
            type boolean;
            description
              "A true value indicates the expObjecID of this row is a
            wildcard object. False indicates that expObjectID is fully
            instanced.  If all expObjectWildcard values for a given
            expression are FALSE, expExpressionPrefix will reflect a
            scalar object (ie will be 0.0).
            
            NOTE:  The simplest implementations of this MIB may not
            allow wildcards.";
          }

          leaf expObjectSampleType {
            smiv2:defval "absoluteValue";
            smiv2:max-access "read-write";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.2.1.4";
            type enumeration {
              enum "absoluteValue" {
                value 1;
              }
              enum "deltaValue" {
                value 2;
              }
            }
            description
              "The method of sampling the selected variable.
            
            An 'absoluteValue' is simply the present value of the
            object.
            A 'deltaValue' is the present value minus the previous
            value, which was sampled expExpressionDeltaInterval
            seconds ago.  This is intended primarily for use with
            SNMP counters, which are meaningless as an 'absoluteValue',
            but may be used with any integer-based value.
            
            When an expression contains both delta and absolute values
            the absolute values are obtained at the end of the delta
            period.";
          }

          leaf expObjectDeltaDiscontinuityID {
            smiv2:defval "sysUpTimeInstance";
            smiv2:max-access "read-write";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.2.1.5";
            type yang:object-identifier-128;
            description
              "The OBJECT IDENTIFIER (OID) of a TimeTicks or TimeStamp
            object that indicates a discontinuity in the value at
            expObjectID.
            
            This object is not instantiated if expObject is not
            'deltaValue'.
            
            The OID may be for a leaf object (e.g. sysUpTime.0) or may
            be wildcarded to match expObjectID.
            
            This object supports normal checking for a discontinuity
            in a counter.  Note that if this object does not point to
            sysUpTime discontinuity checking must still check sysUpTime
            for an overall discontinuity.
            
            If the object identified is not accessible no discontinuity
            check will be made.";
          }

          leaf expObjectDiscontinuityIDWildcard {
            smiv2:defval "false";
            smiv2:max-access "read-write";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.2.1.6";
            type boolean;
            description
              "A true value indicates the expObjectDeltaDiscontinuityID
            of this row is a wildcard object.  False indicates that
            expObjectDeltaDiscontinuityID is fully instanced.
            
            This object is not instantiated if expObject is not
            'deltaValue'.
            
            NOTE:  The simplest implementations of this MIB may not
            allow wildcards.";
          }

          leaf expObjectDiscontinuityIDType {
            smiv2:defval "timeTicks";
            smiv2:max-access "read-write";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.2.1.7";
            type enumeration {
              enum "timeTicks" {
                value 1;
              }
              enum "timeStamp" {
                value 2;
              }
            }
            description
              "The value 'timeTicks' indicates the
            expObjectDeltaDiscontinuityID of this row is of syntax
            TimeTicks.  The value 'timeStamp' indicates that
            expObjectDeltaDiscontinuityID is of syntax TimeStamp.
            
            This object is not instantiated if expObject is not
            'deltaValue'.";
          }

          leaf expObjectConditional {
            smiv2:defval "zeroDotZero";
            smiv2:max-access "read-write";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.2.1.8";
            type yang:object-identifier-128;
            description
              "The OBJECT IDENTIFIER (OID) of an object that overrides
            whether the instance of expObjectID is to be considered
            usable.  If the value of the object at expObjectConditional
            is 0 or not instantiated, the object at expObjectID is
            treated as if it is not instantiated.  In other words,
            expObjectConditional is a filter that controls whether or
            not to use the value at expObjectID.
            
            The OID may be for a leaf object (e.g. sysObjectID.0) or
            may be wildcarded to match expObjectID.  If expObject is
            wildcarded and expObjectID in the same row is not, the wild
            portion of expObjectConditional must match the wildcarding
            of the rest of the expression.  If no object in the
            expression is wildcarded but expObjectConditional is, use
            the lexically first instance (if any) of
            expObjectConditional.
            
            If the value of expObjectConditional is 0.0 operation is
            as if the value pointed to by expObjectConditional is a
            non-zero (true) value.
            
            Note that expObjectConditional can not trivially use an
            object of syntax TruthValue, since the underlying value is
            not 0 or 1.";
          }

          leaf expObjectConditionalWildcard {
            smiv2:defval "false";
            smiv2:max-access "read-write";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.2.1.9";
            type boolean;
            description
              "A true value indicates the expObjectConditional of this
            row is a wildcard object. False indicates that
            expObjectConditional is fully instanced.
            
            NOTE: The simplest implementations of this MIB may not allow
            wildcards.";
          }

          leaf expObjectStatus {
            smiv2:max-access "read-write";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.3.2.1.10";
            type snmpv2-tc:RowStatus;
            description
              "The control that allows creation/deletion of entries.
            
            Objects in this table may be changed while expObjectStatus
            is in any state.";
          }
        }  // list expObjectEntry
      }  // container expObjectTable

      container expValueTable {
        smiv2:oid "1.3.6.1.4.1.9.10.22.1.4.1";
        description
          "A table of values from evaluated expressions.";
        list expValueEntry {
          smiv2:oid "1.3.6.1.4.1.9.10.22.1.4.1.1";
          key "expExpressionIndex expValueInstance";
          description
            "A single value from an evaluated expression.  For a given
          instance, only one 'Val' object in the conceptual row will
          be instantiated, that is, the one with the appropriate type
          for the value.  For values that contain no objects of 
          expObjectSampleType 'deltaValue', reading a value from the
          table causes the evaluation of the expression for that
          value.  For those that contain a 'deltaValue' the value
          read is as of the last delta interval.
          
          If in the attempt to evaluate the expression one or more
          of the necessary objects is not available, the corresponding
          entry in this table is effectively not instantiated.
          
          To maintain security of MIB information, expression
          evaluation must take place using security credentials for
          the implied Gets of the objects in the expression.  For
          expressions with no deltaValue those security credentials
          are the ones that came with the Get* for the value.  For
          expressions with a deltaValue the ongoing expression
          evaluation is under the security credentials of the
          creator of the corresponding expNameEntry.";
          leaf expExpressionIndex {
            type leafref {
              path "/EXPRESSION-MIB:EXPRESSION-MIB/EXPRESSION-MIB:expNameTable/EXPRESSION-MIB:expNameEntry/EXPRESSION-MIB:expExpressionIndex";
            }
          }

          leaf expValueInstance {
            smiv2:max-access "not-accessible";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.4.1.1.1";
            type yang:object-identifier-128;
            description
              "The final instance portion of a value's OID according to
            the wildcarding in instances of expObjectID for the
            expression.  The prefix of this OID fragment is 0.0,
            leading to the following behavior.
            
            If there is no wildcarding, the value is 0.0.0.  In other
            words, there is one value which standing alone would have
            been a scalar with a 0 at the end of its OID.
            
            If there is wildcarding, the value is 0.0 followed by
            a value that the wildcard can take, thus defining one value
            instance for each real, possible value of the wildcard.
            So, for example, if the wildcard worked out to be an
            ifIndex, there is an expValueInstance for each applicable
            ifIndex.";
          }

          leaf expValueCounter32Val {
            smiv2:max-access "read-only";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.4.1.1.2";
            type yang:counter32;
            description
              "The value when expExpressionValueType is 'counter32'.";
          }

          leaf expValueUnsigned32Val {
            smiv2:max-access "read-only";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.4.1.1.3";
            type uint32;
            description
              "The value when expExpressionValueType is
            'unsignedOrGauge32' or 'timeTicks'.";
          }

          leaf expValueInteger32Val {
            smiv2:max-access "read-only";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.4.1.1.4";
            type int32;
            description
              "The value when expExpressionValueType is 'integer32'.";
          }

          leaf expValueIpAddressVal {
            smiv2:max-access "read-only";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.4.1.1.5";
            type inet:ipv4-address;
            description
              "The value when expExpressionValueType is 'ipAddress'.";
          }

          leaf expValueOctetStringVal {
            smiv2:max-access "read-only";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.4.1.1.6";
            type binary {
              length "0..65535";
            }
            description
              "The value when expExpressionValueType is 'octetString'.";
          }

          leaf expValueOidVal {
            smiv2:max-access "read-only";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.4.1.1.7";
            type yang:object-identifier-128;
            description
              "The value when expExpressionValueType is 'objectId'.";
          }

          leaf expValueCounter64Val {
            smiv2:max-access "read-only";
            smiv2:oid "1.3.6.1.4.1.9.10.22.1.4.1.1.8";
            type yang:counter64;
            description
              "The value when expExpressionValueType is 'counter64'.";
          }
        }  // list expValueEntry
      }  // container expValueTable
    }  // container EXPRESSION-MIB
  }  // module EXPRESSION-MIB