Internet Draft Expression MIB 3 June 1997 Expression MIB 3 June 1997 draft-ietf-disman-express-mib-02.txt Bob Stewart Cisco Systems, Inc. bstewart@cisco.com Status of this Memo This document is an Internet-Draft. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet- Drafts as reference material or to cite them other than as ``work in progress.'' To learn the current status of any Internet-Draft, please check the ``1id-abstracts.txt'' listing contained in the Internet- Drafts Shadow Directories on ds.internic.net (US East Coast), nic.nordu.net (Europe), ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific Rim). 9 9Expires 3 June 1997+6 months [Page 1] Internet Draft Expression MIB 3 June 1997 1. Abstract This memo defines an experimental portion of the Management Information Base (MIB) for use with network management protocols in the Internet community. In particular, it describes managed objects used for managing expressions of MIB objects. 9 9Expires 3 June 1997+6 months [Page 2] Internet Draft Expression MIB 3 June 1997 2. The SNMP Network Management Framework They are: The SNMP Network Management Framework presently consists of three major components. They are: the SMI, described in RFC 1902 [1] - the mechanisms used for describing and naming objects for the purpose of management. the MIB-II, STD 17, RFC 1213 [2] - the core set of managed objects for the Internet suite of protocols. the protocol, RFC 1157 [3] and/or RFC 1905 [4], - the protocol for accessing managed objects. The Framework permits new objects to be defined for the purpose of experimentation and evaluation. 2.1. Object Definitions Managed objects are accessed via a virtual information store, termed the Management Information Base or MIB. Objects in the MIB are defined using the subset of Abstract Syntax Notation One (ASN.1) defined in the SMI. In particular, each object type is named by an OBJECT IDENTIFIER, an administratively assigned name. The object type together with an object instance serves to uniquely identify a specific instantiation of the object. For human convenience, we often use a textual string, termed the descriptor, to refer to the object type. 9 9Expires 3 June 1997+6 months [Page 3] Internet Draft Expression MIB 3 June 1997 3. Overview The MIB was designed around the basic premise that an evaluated expression should result in a MIB object that appears no different from any other and is thus usable anywhere any other MIB object can be used, whether by a management application directly or via another MIB. Note that the operation of this MIB depends on the ability to use OID fragments, that is, a part of an OID that may be missing the usual prefix starting with iso. It is the opinion of the author that such a use is legitimate even if it violates some pure definition of ASN.1, since SNMP's use of ASN.1 is colloquial, not standard. The more important test is whether implementations can readily handle such OID fragments, and I believe they should be able to. 9 9Expires 3 June 1997+6 months [Page 4] Internet Draft Expression MIB 3 June 1997 4. Definitions EXPRESSION-MIB DEFINITIONS ::= BEGIN IMPORTS MODULE-IDENTITY, OBJECT-TYPE, experimental, Integer32, Unsigned32, Gauge32 FROM SNMPv2-SMI TEXTUAL-CONVENTION, RowStatus, AutonomousType, DisplayString FROM SNMPv2-TC MODULE-COMPLIANCE, OBJECT-GROUP FROM SNMPv2-CONF; expressionMIB MODULE-IDENTITY LAST-UPDATED "9705301700Z" ORGANIZATION "IETF Distributed Management Working Group" CONTACT-INFO "Bob Stewart Cisco Systems, Inc. 170 West Tasman Drive, San Jose CA 95134-1706. Phone: +1 408 526 4527 Email: bstewart@cisco.com" DESCRIPTION "The MIB module for defining expressions of MIB objects for network management purposes." ::= { experimental xx } ExpressionName ::= TEXTUAL-CONVENTION STATUS current DESCRIPTION "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." SYNTAX DisplayString (SIZE (1..64)) ExpressionIndex ::= TEXTUAL-CONVENTION STATUS current 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." SYNTAX Unsigned32 (1..4294967295) Expires 3 June 1997+6 months [Page 5] Internet Draft Expression MIB 3 June 1997 ExpressionIndexOrZero ::= TEXTUAL-CONVENTION STATUS current DESCRIPTION "Either an ExpressionIndex or zero. The meaning of zero depends on the DESCRIPTION of the object." SYNTAX Unsigned32 (0..4294967295) expressionMIBObjects OBJECT IDENTIFIER ::= { expressionMIB 1 } expResource OBJECT IDENTIFIER ::= { expressionMIBObjects 1 } expName OBJECT IDENTIFIER ::= { expressionMIBObjects 2 } expDefine OBJECT IDENTIFIER ::= { expressionMIBObjects 3 } expValue OBJECT IDENTIFIER ::= { expressionMIBObjects 4 } -- -- Wildcarding Example -- -- This example refers to tables and objects defined below. It may well -- make more sense after reading those definitions. -- -- An expression may use wildcarded MIB objects that result in multiple -- values for the expression. To specify a wildcarded MIB object a -- management application leaves off part or all of the instance portion -- of the object identifier. For our example we'll use a counter of -- total blessings from a table of people. Another table, indexed by town -- and person has blessings just from that town. -- -- So the index clauses are: -- -- personEntry OBJECT-TYPE -- ... -- INDEX { personIndex } -- -- And: -- -- townPersonEntry OBJECT-TYPE -- ... -- INDEX { townIndex, personIndex } -- -- In our friendly application we may have entered our expression as: -- -- 100 * townPersonBlessings.976.* / personBlessings.* Expires 3 June 1997+6 months [Page 6] Internet Draft Expression MIB 3 June 1997 -- -- What goes in expExpression is: -- -- 100*$1/$2 -- -- For example purposes we'll use some slightly far-fetched OIDs, but the -- weirdity won't matter. The People MIB is 1.3.6.1.99.7 and the Town MIB -- is 1.3.6.1.99.11, so for our two counters the OIDs are: -- -- personBlessings 1.3.6.1.99.7.1.3.1.4 -- townPersonBlessings 1.3.6.1.99.11.1.2.1.9 -- -- The rule for wildcards is that all the wildcarded parts have to match -- exactly. In this case that means we have to hardwire the town and only -- the personIndex can be wildcarded. So our values for expObjectID are: -- -- 1.3.6.1.99.7.1.3.1.4 -- 1.3.6.1.99.11.1.2.1.9.976 -- -- We're hardwired to townIndex 976 and personIndex is allowed to vary. -- -- The value of expExpressionPrefix can be either of those two counter OIDs, -- since either of them takes you to a MIB definition where you can look -- at the INDEX clause and figure out what's been left off. What's been -- left off doesn't have to work out to be the same object, but it does -- have to work out to be the same values (semantics). -- -- If we have people numbered 6, 19, and 42 in town number 976, the -- successive values of expValueInstance will be: -- -- 0.0.6 -- 0.0.19 -- 0.0.42 -- -- So there will be three values in expValueTable, with those OIDs as the -- expValueInstance part of their indexing. -- -- -- Resource Control -- expResourceDeltaMinimum OBJECT-TYPE SYNTAX Integer32 (-1 | 1..600) Expires 3 June 1997+6 months [Page 7] Internet Draft Expression MIB 3 June 1997 UNITS "seconds" MAX-ACCESS read-write STATUS current 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." ::= { expResource 1 } expResourceDeltaWildcardInstanceMaximum OBJECT-TYPE SYNTAX Unsigned32 UNITS "instances" MAX-ACCESS read-write STATUS current 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 disturb existing delta wildcard instance state but will inhibit the creation of more." ::= { expResource 2 } expResourceDeltaWildcardInstances OBJECT-TYPE SYNTAX Gauge32 UNITS "instances" MAX-ACCESS read-only Expires 3 June 1997+6 months [Page 8] Internet Draft Expression MIB 3 June 1997 STATUS current DESCRIPTION "The number of currently active instance entries as defined for expResourceDeltaWildcardInstanceMaximum." ::= { expResource 3 } expResourceDeltaWildcardInstancesHigh OBJECT-TYPE SYNTAX Gauge32 UNITS "instances" MAX-ACCESS read-only STATUS current DESCRIPTION "The highest value of expResourceDeltaWildcardInstances that has occurred since initialization of the management system." ::= { expResource 4 } expResourceDeltaWildcardInstanceResourceLacks OBJECT-TYPE SYNTAX Counter32 UNITS "instances" MAX-ACCESS read-only STATUS current DESCRIPTION "The number of times this system could not create an entry that would have exceeded expResourceDeltaWildcardInstanceMaximum." ::= { expResource 5 } -- -- Naming & Creation -- expNameLastChange OBJECT-TYPE SYNTAX TimeStamp MAX-ACCESS read-only STATUS current DESCRIPTION "The value of sysUpTime the last time an expression was created or deleted or had its name changed using expExpressionName." ::= { expName 1 } expNameHighestIndex OBJECT-TYPE SYNTAX ExpressionIndex Expires 3 June 1997+6 months [Page 9] Internet Draft Expression MIB 3 June 1997 MAX-ACCESS read-only STATUS current DESCRIPTION "The highest value of ExpressionIndex ever assigned on this system. 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." ::= { expName 2 } -- -- Name Creation Table -- expNameTable OBJECT-TYPE SYNTAX SEQUENCE OF ExpNameEntry MAX-ACCESS not-accessible STATUS current DESCRIPTION "A table of expression names, for creating and deleting expressions." ::= { expName 3 } expNameEntry OBJECT-TYPE SYNTAX ExpNameEntry MAX-ACCESS not-accessible STATUS current DESCRIPTION "Information about a single expression. New expressions can be created using expNameStatus. To create an expression create the named entry in this table and activate it with RowStatus. Before or after activation, use expExpressionIndex to populate expExpressionTable and expObjectTable. Deleting an entry deletes all related entries in expExpressionTable and expObjectTable. 9 9Expires 3 June 1997+6 months [Page 10] Internet Draft Expression MIB 3 June 1997 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 to require values for expName and expExpressionIndex before any other related obects can be created. If an attempt is made to evaluate a partially defined expression, active rows will exist, rows that are not active will not, and the results will fail accordingly." INDEX { IMPLIED expName } ::= { expNameTable 1 } ExpNameEntry ::= SEQUENCE { expName ExpressionName, expExpressionIndex ExpressionIndex, expNameStatus RowStatus } expName OBJECT-TYPE SYNTAX ExpressionName MAX-ACCESS not-accessible STATUS current 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." ::= { expNameEntry 1 } expExpressionIndex OBJECT-TYPE SYNTAX ExpressionIndex MAX-ACCESS read-create STATUS current 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 acceptible, unused number. 9 9Expires 3 June 1997+6 months [Page 11] Internet Draft Expression MIB 3 June 1997 Once set this value may not be changed." ::= { expNameEntry 2 } expNameStatus OBJECT-TYPE SYNTAX RowStatus MAX-ACCESS read-create STATUS current DESCRIPTION "The control that allows creation/deletion of entries." ::= { expNameEntry 3 } -- -- Definition -- -- Expression Definition Table -- expExpressionTable OBJECT-TYPE SYNTAX SEQUENCE OF ExpExpressionEntry MAX-ACCESS not-accessible STATUS current DESCRIPTION "A table of expression definitions." ::= { expDefine 1 } expExpressionEntry OBJECT-TYPE SYNTAX ExpExpressionEntry MAX-ACCESS not-accessible STATUS current DESCRIPTION "Information about a single expression. An entry appears in this table when an expNameEntry is created. Deleting the matching expNameEntry deletes this entry and its associated expObjectTable entries. Values of read-write objects in this table may be changed at any time." INDEX { expExpressionIndex } ::= { expExpressionTable 1 } ExpExpressionEntry ::= SEQUENCE { expExpressionName ExpressionName, expExpression OCTET STRING, expExpressionComment DisplayString, expExpressionDeltaInterval Integer32, Expires 3 June 1997+6 months [Page 12] Internet Draft Expression MIB 3 June 1997 expExpressionPrefix OBJECT IDENIFIER, expExpressionErrors Counter32, expExpressionErrorTime TimeStamp, expExpressionErrorIndex Integer32, expExpressionError INTEGER, expExpressionInstance OBJECT IDENTIFIER } expExpressionName OBJECT-TYPE SYNTAX ExpressionName MAX-ACCESS read-write STATUS current DESCRIPTION "The unique name of the expression, the same as expName. Use this object to change the expression's name without changing its expExpressionIndex." ::= { expExpressionEntry 1 } expExpression OBJECT-TYPE SYNTAX OCTET STRING (SIZE (1..1024)) MAX-ACCESS read-write STATUS current DESCRIPTION "The expression to be evaluated. Except for the maximum length this object is NVT ASCII, under the same rules as a DisplayString. Except for the variable names the expression is in ANSI C syntax. ANSI C operators and functions are allowed only if explicitly listed here. 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 used recursively, 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 operators and functions allowed are: 9 9Expires 3 June 1997+6 months [Page 13] Internet Draft Expression MIB 3 June 1997 ( ) [ ] + - * / % & | ^ << >> ~ ! && || == != > >= < <= 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 All but oid are as defined for ANSI C. Note that a hexidecimal 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). 9 9Expires 3 June 1997+6 months [Page 14] Internet Draft Expression MIB 3 June 1997 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. The only functions defined are: counter32 counter64 arraySection stringBegins stringEnds stringContains oidBegins oidEnds oidContains sum counter32(integer) - wrapped around an integer value (such as the rest of the expression), counter32 forces the result's expValueType to be 'counter32'. counter64(integer) - similar to counter32 except that the resulting expValueType is 'counter64'. arraySection(array, integer, integer) - selects a piece of an array (i.e. part of an OCTET STRING or OBJECT IDENTIFIER). The integer arguements 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 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 Expires 3 June 1997+6 months [Page 15] Internet Draft Expression MIB 3 June 1997 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(integer*) - sums all avaliable values of the wildcarded integer object, resulting in an integer scalar. Must be used with caution as it wraps on overflow with no notification." DEFVAL { ''H } ::= { expExpressionEntry 2 } expExpressionComment OBJECT-TYPE SYNTAX DisplayString MAX-ACCESS read-write STATUS current DESCRIPTION "A comment to explain the use or meaning of the expression." DEFVAL { ''H } ::= { expExpressionEntry 3 } expExpressionDeltaInterval OBJECT-TYPE SYNTAX Integer32 (0..86400) UNITS "seconds" MAX-ACCESS read-write STATUS current 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. Expires 3 June 1997+6 months [Page 16] Internet Draft Expression MIB 3 June 1997 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. For wildcarded objects this can be substantial overhead." DEFVAL { 0 } ::= { expExpressionEntry 4 } expExpressionPrefix OBJECT-TYPE SYNTAX OBJECT IDENTIFIER MAX-ACCESS read-only STATUS current 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." ::= { expExpressionEntry 5 } expExpressionErrors OBJECT-TYPE SYNTAX Counter32 MAX-ACCESS read-only STATUS current 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." ::= { expExpressionEntry 6 } expExpressionErrorTime OBJECT-TYPE Expires 3 June 1997+6 months [Page 17] Internet Draft Expression MIB 3 June 1997 SYNTAX TimeStamp MAX-ACCESS read-only STATUS current 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." ::= { expExpressionEntry 7 } expExpressionErrorIndex OBJECT-TYPE SYNTAX Integer32 MAX-ACCESS read-only STATUS current DESCRIPTION "The 1-based character index into expExpression for where the error occured. The value zero indicates irrelevance. This object is not instantiated if there have been no errors." ::= { expExpressionEntry 8 } expExpressionError OBJECT-TYPE SYNTAX INTEGER { invalidSyntax(1), undefinedObjectIndex(2), unrecognizedOperator(3), unrecognizedFunction(4), invalidFunctionParameter(5), unmatchedParenthesis(6), tooManyWildcardValues(7), recursion(8) ) MAX-ACCESS read-only STATUS current DESCRIPTION "The error that occurred. Many of these errors should occur when the attempt is made to set expExpression. In those cases the set request will fail with the error code 'wrongValue'. The error 'tooManyWildcardValues' can occur on a set or a get operation. It fails with the error code Expires 3 June 1997+6 months [Page 18] Internet Draft Expression MIB 3 June 1997 'resourceUnavailable'. This object is not instantiated if there have been no errors." ::= { expExpressionEntry 9 } expExpressionInstance OBJECT-TYPE SYNTAX OBJECT IDENTIFIER MAX-ACCESS read-only STATUS current 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." ::= { expExpressionEntry 10 } -- -- Object Table -- expObjectTable OBJECT-TYPE SYNTAX SEQUENCE OF ExpObjectEntry MAX-ACCESS not-accessible STATUS current 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." ::= { expDefine 2 } expObjectEntry OBJECT-TYPE SYNTAX ExpObjectEntry MAX-ACCESS not-accessible Expires 3 June 1997+6 months [Page 19] Internet Draft Expression MIB 3 June 1997 STATUS current 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." INDEX { expExpressionIndex, expObjectIndex } ::= { expObjectTable 1 } ExpObjectEntry ::= SEQUENCE { expObjectIndex Unsigned32, expObjectID OBJECT IDENTIFIER, expObjectSampleType INTEGER, expObjectDeltaDiscontinuityID OBJECT IDENTIFIER, expObjectConditional OBJECT IDENTIFIER, expObjectStatus RowStatus } expObjectIndex OBJECT-TYPE SYNTAX Unsigned32 (1..4294967295) MAX-ACCESS not-accessible STATUS current DESCRIPTION "A unique, numeric identification for an object. Prefixed with a dollar sign ('$') this is used to reference the object in the corresponding expExpression." ::= { expObjectEntry 1 } expObjectID OBJECT-TYPE SYNTAX OBJECT IDENTIFIER MAX-ACCESS read-create STATUS current 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 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. Expires 3 June 1997+6 months [Page 20] Internet Draft Expression MIB 3 June 1997 NOTE: The simplest implementations of this MIB may not allow wildcards." ::= { expObjectEntry 2 } expObjectSampleType OBJECT-TYPE SYNTAX INTEGER { absoluteValue(1), deltaValue(2) } MAX-ACCESS read-create STATUS current DESCRIPTION "The method of sampling the selected variable." DEFVAL { absoluteValue } ::= { expObjectEntry 3 } expObjectDeltaDiscontinuityID OBJECT-TYPE SYNTAX OBJECT IDENTIFIER MAX-ACCESS read-create STATUS current DESCRIPTION "The OBJECT IDENTIFIER (OID) of a TimeTicks object that indicates a discontinuity in the value at expObjectID. This object is not instantiated if not applicable. The OID may be for a leaf object (e.g. sysUpTime.0) or may be wildcarded to match expObjectID. If the object identified is not accessible no discontinuity check will be made." DEFVAL { 0 0 } ::= { expObjectEntry 4 } expObjectConditional OBJECT-TYPE SYNTAX OBJECT IDENTIFIER MAX-ACCESS read-create STATUS current 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, otherwise it is treated as usual. The OID may be for a leaf object (e.g. sysObjectID.0) or may be wildcarded to match expObjectID. Expires 3 June 1997+6 months [Page 21] Internet Draft Expression MIB 3 June 1997 A value of 0.0 is the same as an object with a non-zero (true) value." DEFVAL { 0 0 } ::= { expObjectEntry 5 } expObjectStatus OBJECT-TYPE SYNTAX RowStatus MAX-ACCESS read-create STATUS current DESCRIPTION "The control that allows creation/deletion of entries. Objects in this table may be changed while expObjectStatus is in any state." ::= { expObjectEntry 6 } -- -- Expression Value Table -- expValueTable OBJECT-TYPE SYNTAX SEQUENCE OF ExpValueEntry MAX-ACCESS not-accessible STATUS current DESCRIPTION "A table of values from evaluated expressions." ::= { expValue 1 } expValueEntry OBJECT-TYPE SYNTAX ExpValueEntry MAX-ACCESS not-accessible STATUS current 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. Reading a value from the table causes the evaluation of the expression for that value. 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." INDEX { expExpressionIndex, expValueInstance } ::= { expValueTable 1 } 9 9Expires 3 June 1997+6 months [Page 22] Internet Draft Expression MIB 3 June 1997 ExpValueEntry ::= SEQUENCE { expValueInstance OBJECT IDENTIFIER, expValueType INTEGER, expValueCounter32Val Unsigned32, expValueUnsigned32Val Unsigned32, expValueInteger32Val Integer32, expValueIpAddressVal IpAddress, expValueOctetStringVal OCTET STRING, expValueOidVal OBJECT IDENTIFIER, expValueCounter64Val Counter64 } expValueInstance OBJECT-TYPE SYNTAX OBJECT IDENTIFIER, MAX-ACCESS not-accessible STATUS current 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." ::= { expValueEntry 1 } expValueType OBJECT-TYPE SYNTAX INTEGER { counter32(1), unsignedOrGauge32(2), timeTicks(3), integer32(4), ipAddress(5), octetString(6), objectId(7), counter64(8) } MAX-ACCESS read-only STATUS current DESCRIPTION "The type of the value. One and only one of the value objects that follow will be instantiated based on this type." ::= { expValueEntry 2 } expValueCounter32Val OBJECT-TYPE Expires 3 June 1997+6 months [Page 23] Internet Draft Expression MIB 3 June 1997 SYNTAX Counter32 MAX-ACCESS read-only STATUS current DESCRIPTION "The value when expValueType is of 'counter32'." ::= { expValueEntry 3 } expValueUnsigned32Val OBJECT-TYPE SYNTAX Unsigned32 MAX-ACCESS read-only STATUS current DESCRIPTION "The value when expValueType is one of 'unsignedOrGauge32' or 'timeTicks'." ::= { expValueEntry 4 } expValueInteger32Val OBJECT-TYPE SYNTAX Integer32 MAX-ACCESS read-only STATUS current DESCRIPTION "The value when expValueType is 'integer32'." ::= { expValueEntry 5 } expValueOctetStringVal OBJECT-TYPE SYNTAX IpAddress MAX-ACCESS read-only STATUS current DESCRIPTION "The value when expValueType is 'ipAddress'." ::= { expValueEntry 6 } expValueOctetStringVal OBJECT-TYPE SYNTAX OCTET STRING (SIZE (0..65536)) MAX-ACCESS read-only STATUS current DESCRIPTION "The value when expValueType is 'octetString'." ::= { expValueEntry 7 } expValueOidVal OBJECT-TYPE SYNTAX OBJECT IDENTIFIER MAX-ACCESS read-only STATUS current DESCRIPTION Expires 3 June 1997+6 months [Page 24] Internet Draft Expression MIB 3 June 1997 "The value when expValueType is 'objectId'." ::= { expValueEntry 8 } expValueCounter64Val OBJECT-TYPE SYNTAX Counter64 MAX-ACCESS read-only STATUS current DESCRIPTION "The value when expValueType is 'counter64'." ::= { expValueEntry 9 } -- -- Conformance -- expressionMIBConformance OBJECT IDENTIFIER ::= { expressionMIB 3 } expressionMIBCompliances OBJECT IDENTIFIER ::= { expressionMIBConformance 1 } expressionMIBGroups OBJECT IDENTIFIER ::= { expressionMIBConformance 2 } -- Compliance expressionMIBCompliance MODULE-COMPLIANCE STATUS current DESCRIPTION "The compliance statement for entities which implement the Expression MIB." MODULE -- this module MANDATORY-GROUPS { expressionResourceGroup, expressionDefinitionGroup, expressionValueGroup } OBJECT expResourceDeltaMinimum SYNTAX Integer32 ( -1 ) DESCRIPTION "Implementation need not allow deltas." OBJECT expResourceDeltaMinimum SYNTAX Integer32 (60..600) DESCRIPTION "Implementation may restrict deltas to higher values." OBJECT expObjectSampleType WRITE-SYNTAX INTEGER { absoluteValue(1) } Expires 3 June 1997+6 months [Page 25] Internet Draft Expression MIB 3 June 1997 DESCRIPTION "Implementation may not allow deltas." ::= { expressionMIBCompliances 1 } -- Units of Conformance expressionResourceGroup OBJECT-GROUP OBJECTS { expResourceDeltaMinimum, expResourceDeltaWildcardInstanceMaximum, expResourceDeltaWildcardInstances, expResourceDeltaWildcardInstancesHigh, expResourceDeltaWildcardInstanceResourceLacks } STATUS current DESCRIPTION "Expression definition resource management." ::= { expressionMIBGroups 1 } expressionDefinitionGroup OBJECT-GROUP OBJECTS { expNameLastChange, expNameHighestIndex, expExpressionIndex, expNameStatus, expExpressionName, expExpression, expExpressionComment, expExpressionDeltaInterval, expExpressionPrefix, expExpressionErrors, expExpressionErrorTime, expExpressionErrorIndex, expExpressionError, expExpressionInstance, expObjectID, expObjectSampleType, expObjectDeltaDiscontinuityID, expObjectConditional, expObjectStatus } STATUS current Expires 3 June 1997+6 months [Page 26] Internet Draft Expression MIB 3 June 1997 DESCRIPTION "Expression definition resource management." ::= { expressionMIBGroups 1 } expressionValueGroup OBJECT-GROUP OBJECTS { expValueType, expValueCounter32Val, expValueUnsigned32Val, expValueInteger32Val, expValueIpAddressVal, expValueOctetStringVal, expValueOidVal, expValueCounter64Val } STATUS current DESCRIPTION "Expression definition resource management." ::= { expressionMIBGroups 1 } END 9 9Expires 3 June 1997+6 months [Page 27] Internet Draft Expression MIB 3 June 1997 5. Acknowledgements This MIB contains considerable contributions from the RMON MIB, the Distributed Management Design Team (Andy Bierman, Maria Greene, Bob Stewart, and Steve Waldbusser), and colleagues at Cisco. 9 9Expires 3 June 1997+6 months [Page 28] Internet Draft Expression MIB 3 June 1997 6. References [1] SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Structure of Management Information for version 2 of the Simple Network Management Protocol (SNMPv2)", RFC 1902, January 1996. [2] McCloghrie, K., and M. Rose, Editors, "Management Information Base for Network Management of TCP/IP-based internets: MIB-II", STD 17, RFC 1213, March 1991. [3] Case, J., Fedor, M., Schoffstall, M., and J. Davin, "Simple Network Management Protocol", RFC 1157, May 1990. [4] SNMPv2 Working Group, Case, J., McCloghrie, K., Rose, M., and S. Waldbusser, "Protocol Operations for version 2 of the Simple Network Management Protocol (SNMPv2)", RFC 1905, January 1996. 9 9Expires 3 June 1997+6 months [Page 29] Internet Draft Expression MIB 3 June 1997 7. Security Considerations Security issues are not discussed in this memo. 8. Author's Address Bob Stewart Cisco Systems, Inc. 170 West Tasman Drive San Jose, CA 95134-1706 Phone: 408-526-4527 Email: bstewart@cisco.com 9 9Expires 3 June 1997+6 months [Page 30] Internet Draft Expression MIB 3 June 1997 Table of Contents 1 Abstract ........................................................ 2 2 The SNMP Network Management Framework ........................... 3 2.1 Object Definitions ............................................ 3 3 Overview ........................................................ 4 4 Definitions ..................................................... 5 5 Acknowledgements ................................................ 28 6 References ...................................................... 29 7 Security Considerations ......................................... 30 8 Author's Address ................................................ 30 9 9Expires 3 June 1997+6 months [Page 31]