| expResourceDeltaMinimum |
.1.3.6.1.4.1.9.10.22.1.1.1 |
|
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.
|
| expResourceDeltaWildcardInstanceMaximum |
.1.3.6.1.4.1.9.10.22.1.1.2 |
|
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.
|
| expResourceDeltaWildcardInstances |
.1.3.6.1.4.1.9.10.22.1.1.3 |
|
The number of currently active instance entries as
defined for expResourceDeltaWildcardInstanceMaximum.
|
| expResourceDeltaWildcardInstancesHigh |
.1.3.6.1.4.1.9.10.22.1.1.4 |
|
The highest value of expResourceDeltaWildcardInstances
that has occurred since initialization of the management
system.
|
| expResourceDeltaWildcardInstanceResourceLacks |
.1.3.6.1.4.1.9.10.22.1.1.5 |
|
The number of times this system could not evaluate an expression
because that would have created a value instance in excess of
expResourceDeltaWildcardInstanceMaximum.
|
| expNameLastChange |
.1.3.6.1.4.1.9.10.22.1.2.1 |
|
The value of sysUpTime the last time an expression was
created or deleted or had its name changed using
expExpressionName.
|
| expNameHighestIndex |
.1.3.6.1.4.1.9.10.22.1.2.2 |
|
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.
|
| expNameEntry |
.1.3.6.1.4.1.9.10.22.1.2.3.1 |
|
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.
|
| expExpressionEntry |
.1.3.6.1.4.1.9.10.22.1.3.1.1 |
|
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.
|
| expObjectEntry |
.1.3.6.1.4.1.9.10.22.1.3.2.1 |
|
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.
|
| expValueEntry |
.1.3.6.1.4.1.9.10.22.1.4.1.1 |
|
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.
|
| expName |
.1.3.6.1.4.1.9.10.22.1.2.3.1.1 |
|
The name of the expression. Choosing names with useful
lexical ordering supports using GetNext or GetBulk to
retrieve a useful subset of the table.
|
| expExpressionIndex |
.1.3.6.1.4.1.9.10.22.1.2.3.1.2 |
|
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.
|
| expNameStatus |
.1.3.6.1.4.1.9.10.22.1.2.3.1.3 |
|
The control that allows creation/deletion of entries.
|
| expExpressionName |
.1.3.6.1.4.1.9.10.22.1.3.1.1.1 |
|
The unique name of the expression, the same as expName.
Use this object to change the expression's name without
changing its expExpressionIndex.
|
| expExpression |
.1.3.6.1.4.1.9.10.22.1.3.1.1.2 |
|
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).
|
| expExpressionValueType |
.1.3.6.1.4.1.9.10.22.1.3.1.1.3 |
|
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.
|
| expExpressionComment |
.1.3.6.1.4.1.9.10.22.1.3.1.1.4 |
|
A comment to explain the use or meaning of the expression.
|
| expExpressionDeltaInterval |
.1.3.6.1.4.1.9.10.22.1.3.1.1.5 |
|
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.
|
| expExpressionPrefix |
.1.3.6.1.4.1.9.10.22.1.3.1.1.6 |
|
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.
|
| expExpressionErrors |
.1.3.6.1.4.1.9.10.22.1.3.1.1.7 |
|
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.
|
| expExpressionErrorTime |
.1.3.6.1.4.1.9.10.22.1.3.1.1.8 |
|
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.
|
| expExpressionErrorIndex |
.1.3.6.1.4.1.9.10.22.1.3.1.1.9 |
|
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.
|
| expExpressionError |
.1.3.6.1.4.1.9.10.22.1.3.1.1.10 |
|
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 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.
|
| expExpressionInstance |
.1.3.6.1.4.1.9.10.22.1.3.1.1.11 |
|
The expValueInstance being evaluated when the error
occurred. A zero-length indicates irrelevance.
This object is not instantiated if there have been no
errors.
|
| expExpressionOwner |
.1.3.6.1.4.1.9.10.22.1.3.1.1.12 |
|
The entity that configured this entry and is therefore using the
resources assigned to it.
|
| expObjectIndex |
.1.3.6.1.4.1.9.10.22.1.3.2.1.1 |
|
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.
|
| expObjectID |
.1.3.6.1.4.1.9.10.22.1.3.2.1.2 |
|
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.
|
| expObjectIDWildcard |
.1.3.6.1.4.1.9.10.22.1.3.2.1.3 |
|
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.
|
| expObjectSampleType |
.1.3.6.1.4.1.9.10.22.1.3.2.1.4 |
|
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.
|
| expObjectDeltaDiscontinuityID |
.1.3.6.1.4.1.9.10.22.1.3.2.1.5 |
|
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.
|
| expObjectDiscontinuityIDWildcard |
.1.3.6.1.4.1.9.10.22.1.3.2.1.6 |
|
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.
|
| expObjectDiscontinuityIDType |
.1.3.6.1.4.1.9.10.22.1.3.2.1.7 |
|
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'.
|
| expObjectConditional |
.1.3.6.1.4.1.9.10.22.1.3.2.1.8 |
|
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.
|
| expObjectConditionalWildcard |
.1.3.6.1.4.1.9.10.22.1.3.2.1.9 |
|
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.
|
| expObjectStatus |
.1.3.6.1.4.1.9.10.22.1.3.2.1.10 |
|
The control that allows creation/deletion of entries.
Objects in this table may be changed while expObjectStatus
is in any state.
|
| expValueInstance |
.1.3.6.1.4.1.9.10.22.1.4.1.1.1 |
|
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.
|
| expValueCounter32Val |
.1.3.6.1.4.1.9.10.22.1.4.1.1.2 |
|
The value when expExpressionValueType is 'counter32'.
|
| expValueUnsigned32Val |
.1.3.6.1.4.1.9.10.22.1.4.1.1.3 |
|
The value when expExpressionValueType is 'unsignedOrGauge32'
or 'timeTicks'.
|
| expValueInteger32Val |
.1.3.6.1.4.1.9.10.22.1.4.1.1.4 |
|
The value when expExpressionValueType is 'integer32'.
|
| expValueIpAddressVal |
.1.3.6.1.4.1.9.10.22.1.4.1.1.5 |
|
The value when expExpressionValueType is 'ipAddress'.
|
| expValueOctetStringVal |
.1.3.6.1.4.1.9.10.22.1.4.1.1.6 |
|
The value when expExpressionValueType is 'octetString'.
|
| expValueOidVal |
.1.3.6.1.4.1.9.10.22.1.4.1.1.7 |
|
The value when expExpressionValueType is 'objectId'.
|
| expValueCounter64Val |
.1.3.6.1.4.1.9.10.22.1.4.1.1.8 |
|
The value when expExpressionValueType is 'counter64'.
|
