| OID symbolic | OID numeric | Type | Access | Description |
|---|
| sysUpTimeInstance | 1.3.6.1.2.1.1.3.0 | | | |
| dismanExpressionMIB | 1.3.6.1.2.1.90 | | | The MIB module for defining expressions of MIB objects for
management purposes. |
| dismanExpressionMIBObjects | 1.3.6.1.2.1.90.1 | | | |
| expResource | 1.3.6.1.2.1.90.1.1 | | | |
| I32 expResourceDeltaMinimum | 1.3.6.1.2.1.90.1.1.1 | Integer32 | read-write | 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. For larger
delta sampling intervals the system samples less often and
suffers less overhead. This object provides a way to enforce
such lower overhead for all expressions created after it is
set.
The value -1 indicates that expResourceDeltaMinimum is
irrelevant as the system will not accept 'deltaValue' as a
value for expObjectSampleType.
Unless explicitly resource limited, a system's value for
this object should be 1, allowing as small as a 1 second
interval for ongoing delta sampling.
Changing this value will not invalidate an existing setting
of expObjectSampleType. |
| U32 expResourceDeltaWildcardInstanceMaximum | 1.3.6.1.2.1.90.1.1.2 | Unsigned32 | read-write | For every instance of a deltaValue object, one dynamic instance
entry is needed for holding the instance value from the previous
sample, i.e. to maintain state.
This object limits maximum number of dynamic instance entries
this system will support for wildcarded delta objects in
expressions. For a given delta expression, the number of
dynamic instances is the number of values that meet all criteria
to exist times the number of delta values in the 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.
An attempt to allocate beyond the limit results in expErrorCode
being tooManyWildcardValues for that evaluation attempt. |
| G32 expResourceDeltaWildcardInstances | 1.3.6.1.2.1.90.1.1.3 | Gauge32 | read-only | The number of currently active instance entries as
defined for expResourceDeltaWildcardInstanceMaximum. |
| G32 expResourceDeltaWildcardInstancesHigh | 1.3.6.1.2.1.90.1.1.4 | Gauge32 | read-only | The highest value of expResourceDeltaWildcardInstances
that has occurred since initialization of the managed
system. |
| C32 expResourceDeltaWildcardInstanceResourceLacksEx | 1.3.6.1.2.1.90.1.1.5 | Counter32 | read-only | The number of times this system could not evaluate an
expression because that would have created a value instance in
excess of expResourceDeltaWildcardInstanceMaximum. |
| expDefine | 1.3.6.1.2.1.90.1.2 | | | |
| expExpressionTable | 1.3.6.1.2.1.90.1.2.1 | | not-accessible | A table of expression definitions. |
| expExpressionEntry | 1.3.6.1.2.1.90.1.2.1.1 | | not-accessible | Information about a single expression. New expressions
can be created using expExpressionRowStatus.
To create an expression first create the named entry in this
table. Then use expExpressionName to populate expObjectTable.
For expression evaluation to succeed all related entries in
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 expObjectTable
and expErrorTable.
Because of the relationships among the multiple tables for an
expression (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 or a delta interval expires. Earlier
checking need not be done and an implementation may not impose
any ordering on the creation of objects related to an
expression.
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. These security credentials are the parameters
necessary as inputs to isAccessAllowed from the Architecture for
Describing SNMP Management Frameworks. When obtaining the objects
that make up the expression, the system must (conceptually) use
isAccessAllowed to ensure that it does not violate security.
The evaluation of the expression takes place under the
security credentials of the creator of its expExpressionEntry.
Values of read-write objects in this table may be changed
at any time. |
| STR expExpressionOwner | 1.3.6.1.2.1.90.1.2.1.1.1 | SnmpAdminString | not-accessible | The owner of this entry. The exact semantics of this
string are subject to the security policy defined by the
security administrator. |
| STR expExpressionName | 1.3.6.1.2.1.90.1.2.1.1.2 | SnmpAdminString | not-accessible | The name of the expression. This is locally unique, within
the scope of an expExpressionOwner. |
| OCT expExpression | 1.3.6.1.2.1.90.1.2.1.1.3 | OCTET STRING | read-create | 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 must not be recursive, that is although an expression
may use the results of another expression, it must not contain
any variable that is directly or indirectly a result of its own
evaluation. The managed system must check for recursive
expressions.
The only allowed operators are:
( )
- (unary)
+ - * / %
& | ^ > ~
! && || == != > >= > 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 >= work with
TimeTicks.
The operators &, |, and ^ work with IpAddress.
The operators > 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 > 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
average
maximum
minimum
sum
exists
The following function definitions indicate their parameters 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 (one-dimensioned) 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 one-dimensioned arrayindex 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 one-dimensioned index where the match began. A return value
of 0 indicates no match (i.e. boolean false).
average/maximum/minimum(integer) - calculates the average,
minimum, or maximum value of the integer valued object over
multiple sample times. If the object disappears for any
sample period, the accumulation and the resulting value object
cease to exist until the object reappears at which point the
calculation starts over.
sum(integerObject*) - sums all available 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). |
| INT expExpressionValueType | 1.3.6.1.2.1.90.1.2.1.1.4 | INTEGER | read-create | 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. |
| I32 expExpressionDeltaInterval | 1.3.6.1.2.1.90.1.2.1.1.6 | Integer32 | read-create | Sampling interval for objects in this expression with
expObjectSampleType 'deltaValue'.
This object has no effect if the the expression has no
deltaValue objects.
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. So, for example,
to avoid the higher level getting the same sample twice, the
lower level should sample at least twice as fast as the higher
level does. |
| OID expExpressionPrefix | 1.3.6.1.2.1.90.1.2.1.1.7 | OBJECT IDENTIFIER | read-only | 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.
Note that zero length implies a null OID, not the OID 0.0.
Otherwise, the value of expExpressionPrefix is the expObjectID
value of any one of the wildcarded objects 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. |
| C32 expExpressionErrors | 1.3.6.1.2.1.90.1.2.1.1.8 | Counter32 | read-only | The number of errors encountered while evaluating this
expression.
Note that an object in the expression not being accessible,
is not considered an error. An example of an inaccessible
object is when the object is excluded from the view of the
user whose security credentials are used in the expression
evaluation. In such cases, it is a legitimate condition
that causes the corresponding expression value not to be
instantiated. |
| ROW expExpressionEntryStatus | 1.3.6.1.2.1.90.1.2.1.1.9 | RowStatus | read-create | The control that allows creation and deletion of entries. |
| expErrorTable | 1.3.6.1.2.1.90.1.2.2 | | not-accessible | A table of expression errors. |
| expErrorEntry | 1.3.6.1.2.1.90.1.2.2.1 | | not-accessible | Information about errors in processing an expression.
Entries appear in this table only when there is a matching
expExpressionEntry and then only when there has been an
error for that expression as reflected by the error codes
defined for expErrorCode. |
| TIM expErrorTime | 1.3.6.1.2.1.90.1.2.2.1.1 | TimeStamp | read-only | The value of sysUpTime the last time an error caused a
failure to evaluate this expression. |
| I32 expErrorIndex | 1.3.6.1.2.1.90.1.2.2.1.2 | Integer32 | read-only | The one-dimensioned character array index into
expExpression for where the error occurred. The value
zero indicates irrelevance. |
| INT expErrorCode | 1.3.6.1.2.1.90.1.2.2.1.3 | INTEGER | read-only | 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
expResourceDeltaWildcardInstanceMaximum
(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 evaluation for a Get* operation return
the SNMP error code 'genErr' except for 'tooManyWildcardValues'
and 'resourceUnavailable' which return the SNMP error code
'resourceUnavailable'. |
| OID expErrorInstance | 1.3.6.1.2.1.90.1.2.2.1.4 | OBJECT IDENTIFIER | read-only | The expValueInstance being evaluated when the error
occurred. A zero-length indicates irrelevance. |
| expObjectTable | 1.3.6.1.2.1.90.1.2.3 | | not-accessible | 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. |
| expObjectEntry | 1.3.6.1.2.1.90.1.2.3.1 | | not-accessible | Information about an object. An application uses
expObjectEntryStatus 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. |
| U32 expObjectIndex | 1.3.6.1.2.1.90.1.2.3.1.1 | Unsigned32 | not-accessible | 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. |
| OID expObjectID | 1.3.6.1.2.1.90.1.2.3.1.2 | OBJECT IDENTIFIER | read-create | 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. |
| T/F expObjectIDWildcard | 1.3.6.1.2.1.90.1.2.3.1.3 | TruthValue | read-create | 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 (i.e. will
be 0.0).
NOTE: The simplest implementations of this MIB may not allow
wildcards. |
| INT expObjectSampleType | 1.3.6.1.2.1.90.1.2.3.1.4 | INTEGER | read-create | 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.
A 'changedValue' is a boolean for whether the present value is
different from the previous value. It is applicable to any data
type and results in an Unsigned32 with value 1 if the object's
value is changed and 0 if not. In all other respects it is as a
'deltaValue' and all statements and operation regarding delta
values apply to changed values.
When an expression contains both delta and absolute values
the absolute values are obtained at the end of the delta
period. |
| OID expObjectDeltaDiscontinuityID | 1.3.6.1.2.1.90.1.2.3.1.5 | OBJECT IDENTIFIER | read-create | The OBJECT IDENTIFIER (OID) of a TimeTicks, TimeStamp, or
DateAndTime object that indicates a discontinuity in the value
at expObjectID.
This object is instantiated only if expObjectSampleType is
'deltaValue' or 'changedValue'.
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. |
| T/F expObjectDiscontinuityIDWildcard | 1.3.6.1.2.1.90.1.2.3.1.6 | TruthValue | read-create | A true value indicates the expObjectDeltaDiscontinuityID of
this row is a wildcard object. False indicates that
expObjectDeltaDiscontinuityID is fully instanced.
This object is instantiated only if expObjectSampleType is
'deltaValue' or 'changedValue'.
NOTE: The simplest implementations of this MIB may not allow
wildcards. |
| INT expObjectDiscontinuityIDType | 1.3.6.1.2.1.90.1.2.3.1.7 | INTEGER | read-create | The value 'timeTicks' indicates the expObjectDeltaDiscontinuityID
of this row is of syntax TimeTicks. The value 'timeStamp' indicates
syntax TimeStamp. The value 'dateAndTime indicates syntax
DateAndTime.
This object is instantiated only if expObjectSampleType is
'deltaValue' or 'changedValue'. |
| OID expObjectConditional | 1.3.6.1.2.1.90.1.2.3.1.8 | OBJECT IDENTIFIER | read-create | 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. |
| T/F expObjectConditionalWildcard | 1.3.6.1.2.1.90.1.2.3.1.9 | TruthValue | read-create | 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. |
| ROW expObjectEntryStatus | 1.3.6.1.2.1.90.1.2.3.1.10 | RowStatus | read-create | The control that allows creation/deletion of entries.
Objects in this table may be changed while
expObjectEntryStatus is in any state. |
| expValue | 1.3.6.1.2.1.90.1.3 | | | |
| expValueTable | 1.3.6.1.2.1.90.1.3.1 | | not-accessible | A table of values from evaluated expressions. |
| expValueEntry | 1.3.6.1.2.1.90.1.3.1.1 | | not-accessible | 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' or 'changedValue', reading a
value from the table causes the evaluation of the expression
for that value. For those that contain a 'deltaValue' or
'changedValue' the value read is as of the last sampling
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, when creating a new
row in this table, the managed system must record the security
credentials of the requester. These security credentials are
the parameters necessary as inputs to isAccessAllowed from
[RFC2571]. When obtaining the objects that make up the
expression, the system must (conceptually) use isAccessAllowed to
ensure that it does not violate security.
The evaluation of that expression takes place under the
security credentials of the creator of its expExpressionEntry.
To maintain security of MIB information, expression evaluation must
take place using security credentials for the implied Gets of the
objects in the expression as inputs (conceptually) to
isAccessAllowed from the Architecture for Describing SNMP
Management Frameworks. These are the security credentials of the
creator of the corresponding expExpressionEntry. |
| OID expValueInstance | 1.3.6.1.2.1.90.1.3.1.1.1 | OBJECT IDENTIFIER | not-accessible | 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. |
| C32 expValueCounter32Val | 1.3.6.1.2.1.90.1.3.1.1.2 | Counter32 | read-only | The value when expExpressionValueType is 'counter32'. |
| U32 expValueUnsigned32Val | 1.3.6.1.2.1.90.1.3.1.1.3 | Unsigned32 | read-only | The value when expExpressionValueType is 'unsigned32'. |
| TIK expValueTimeTicksVal | 1.3.6.1.2.1.90.1.3.1.1.4 | TimeTicks | read-only | The value when expExpressionValueType is 'timeTicks'. |
| I32 expValueInteger32Val | 1.3.6.1.2.1.90.1.3.1.1.5 | Integer32 | read-only | The value when expExpressionValueType is 'integer32'. |
| IP expValueIpAddressVal | 1.3.6.1.2.1.90.1.3.1.1.6 | IpAddress | read-only | The value when expExpressionValueType is 'ipAddress'. |
| OCT expValueOctetStringVal | 1.3.6.1.2.1.90.1.3.1.1.7 | OCTET STRING | read-only | The value when expExpressionValueType is 'octetString'. |
| OID expValueOidVal | 1.3.6.1.2.1.90.1.3.1.1.8 | OBJECT IDENTIFIER | read-only | The value when expExpressionValueType is 'objectId'. |
| C64 expValueCounter64Val | 1.3.6.1.2.1.90.1.3.1.1.9 | Counter64 | read-only | The value when expExpressionValueType is 'counter64'. |
| dismanExpressionMIBConformance | 1.3.6.1.2.1.90.3 | | | |
| dismanExpressionMIBCompliances | 1.3.6.1.2.1.90.3.1 | | | |
| dismanExpressionMIBCompliance | 1.3.6.1.2.1.90.3.1.1 | | | The compliance statement for entities which implement
the Expression MIB. |
| dismanExpressionMIBGroups | 1.3.6.1.2.1.90.3.2 | | | |
| dismanExpressionResourceGroup | 1.3.6.1.2.1.90.3.2.1 | | | Expression definition resource management. |
| dismanExpressionDefinitionGroup | 1.3.6.1.2.1.90.3.2.2 | | | Expression definition. |
| dismanExpressionValueGroup | 1.3.6.1.2.1.90.3.2.3 | | | Expression value. |
