rfc1903.txt

著名的RFC文档,其中有一些文档是已经翻译成中文的的.

                 - the exception `noSuchInstance' is returned,
                 indicating that the agent implements the object-type
                 associated with this column, and that this column in at
                 least one conceptual row would be accessible in the MIB
                 view used by the retrieval were it to exist. For those
                 columns to which the agent provides read-create access,
                 the `noSuchInstance' exception tells the management
                 station that it should supply a value for this column
                 when the conceptual row is to be created.

                 - the exception `noSuchObject' is returned, indicating
                 that the agent does not implement the object-type
                 associated with this column or that there is no
                 conceptual row for which this column would be
                 accessible in the MIB view used by the retrieval.  As
                 such, the management station can not issue any
                 management protocol set operations to create an
                 instance of this column.

            Once the column requirements have been determined, a
            management protocol set operation is accordingly issued.
            This operation also sets the new instance of the status
            column to `createAndGo'.




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            When the agent processes the set operation, it verifies that
            it has sufficient information to make the conceptual row
            available for use by the managed device.  The information
            available to the agent is provided by two sources:  the
            management protocol set operation which creates the
            conceptual row, and, implementation-specific defaults
            supplied by the agent (note that an agent must provide
            implementation-specific defaults for at least those objects
            which it implements as read-only).  If there is sufficient
            information available, then the conceptual row is created, a
            `noError' response is returned, the status column is set to
            `active', and no further interactions are necessary (i.e.,
            interactions 3 and 4 are skipped).  If there is insufficient
            information, then the conceptual row is not created, and the
            set operation fails with an error of `inconsistentValue'.
            On this error, the management station can issue a management
            protocol retrieval operation to determine if this was
            because it failed to specify a value for a required column,
            or, because the selected instance of the status column
            already existed.  In the latter case, we return to
            interaction 1.  In the former case, the management station
            can re-issue the set operation with the additional
            information, or begin interaction 2 again using
            `createAndWait' in order to negotiate creation of the
            conceptual row.

                                     NOTE WELL

                 Regardless of the method used to determine the column
                 requirements, it is possible that the management
                 station might deem a column necessary when, in fact,
                 the agent will not allow that particular columnar
                 instance to be created or written.  In this case, the
                 management protocol set operation will fail with an
                 error such as `noCreation' or `notWritable'.  In this
                 case, the management station decides whether it needs
                 to be able to set a value for that particular columnar
                 instance.  If not, the management station re-issues the
                 management protocol set operation, but without setting
                 a value for that particular columnar instance;
                 otherwise, the management station aborts the row
                 creation algorithm.

            Interaction 2b: Negotiating the Creation of the Conceptual
            Row

            The management station issues a management protocol set
            operation which sets the desired instance of the status



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            column to `createAndWait'.  If the agent is unwilling to
            process a request of this sort, the set operation fails with
            an error of `wrongValue'.  (As a consequence, such an agent
            must be prepared to accept a single management protocol set
            operation, i.e., interaction 2a above, containing all of the
            columns indicated by its column requirements.)  Otherwise,
            the conceptual row is created, a `noError' response is
            returned, and the status column is immediately set to either
            `notInService' or `notReady', depending on whether it has
            sufficient information to make the conceptual row available
            for use by the managed device.  If there is sufficient
            information available, then the status column is set to
            `notInService'; otherwise, if there is insufficient
            information, then the status column is set to `notReady'.
            Regardless, we proceed to interaction 3.

            Interaction 3: Initializing non-defaulted Objects

            The management station must now determine the column
            requirements.  It issues a management protocol get operation
            to examine all columns in the created conceptual row.  In
            the response, for each column, there are three possible
            outcomes:

                 - a value is returned, indicating that the agent
                 implements the object-type associated with this column
                 and had sufficient information to provide a value.  For
                 those columns to which the agent provides read-create
                 access (and for which the agent allows their values to
                 be changed after their creation), a value return tells
                 the management station that it may issue additional
                 management protocol set operations, if it desires, in
                 order to change the value associated with this column.

                 - the exception `noSuchInstance' is returned,
                 indicating that the agent implements the object-type
                 associated with this column, and that this column in at
                 least one conceptual row would be accessible in the MIB
                 view used by the retrieval were it to exist. However,
                 the agent does not have sufficient information to
                 provide a value, and until a value is provided, the
                 conceptual row may not be made available for use by the
                 managed device.  For those columns to which the agent
                 provides read-create access, the `noSuchInstance'
                 exception tells the management station that it must
                 issue additional management protocol set operations, in
                 order to provide a value associated with this column.




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RFC 1903             Textual Conventions for SNMPv2         January 1996


                 - the exception `noSuchObject' is returned, indicating
                 that the agent does not implement the object-type
                 associated with this column or that there is no
                 conceptual row for which this column would be
                 accessible in the MIB view used by the retrieval.  As
                 such, the management station can not issue any
                 management protocol set operations to create an
                 instance of this column.

            If the value associated with the status column is
            `notReady', then the management station must first deal with
            all `noSuchInstance' columns, if any.  Having done so, the
            value of the status column becomes `notInService', and we
            proceed to interaction 4.

            Interaction 4: Making the Conceptual Row Available

            Once the management station is satisfied with the values
            associated with the columns of the conceptual row, it issues
            a management protocol set operation to set the status column
            to `active'.  If the agent has sufficient information to
            make the conceptual row available for use by the managed
            device, the management protocol set operation succeeds (a
            `noError' response is returned).  Otherwise, the management
            protocol set operation fails with an error of
            `inconsistentValue'.


                                     NOTE WELL

                 A conceptual row having a status column with value
                 `notInService' or `notReady' is unavailable to the
                 managed device.  As such, it is possible for the
                 managed device to create its own instances during the
                 time between the management protocol set operation
                 which sets the status column to `createAndWait' and the
                 management protocol set operation which sets the status
                 column to `active'.  In this case, when the management
                 protocol set operation is issued to set the status
                 column to `active', the values held in the agent
                 supersede those used by the managed device.

            If the management station is prevented from setting the
            status column to `active' (e.g., due to management station
            or network failure) the conceptual row will be left in the
            `notInService' or `notReady' state, consuming resources
            indefinitely.  The agent must detect conceptual rows that
            have been in either state for an abnormally long period of



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            time and remove them.  It is the responsibility of the
            DESCRIPTION clause of the status column to indicate what an
            abnormally long period of time would be.  This period of
            time should be long enough to allow for human response time
            (including `think time') between the creation of the
            conceptual row and the setting of the status to `active'.
            In the absense of such information in the DESCRIPTION
            clause, it is suggested that this period be approximately 5
            minutes in length.  This removal action applies not only to
            newly-created rows, but also to previously active rows which
            are set to, and left in, the notInService state for a
            prolonged period exceeding that which is considered normal
            for such a conceptual row.


                             Conceptual Row Suspension

            When a conceptual row is `active', the management station
            may issue a management protocol set operation which sets the
            instance of the status column to `notInService'.  If the
            agent is unwilling to do so, the set operation fails with an
            error of `wrongValue'.  Otherwise, the conceptual row is
            taken out of service, and a `noError' response is returned.
            It is the responsibility of the DESCRIPTION clause of the
            status column to indicate under what circumstances the
            status column should be taken out of service (e.g., in order
            for the value of some other column of the same conceptual
            row to be modified).


                              Conceptual Row Deletion

            For deletion of conceptual rows, a management protocol set
            operation is issued which sets the instance of the status
            column to `destroy'.  This request may be made regardless of
            the current value of the status column (e.g., it is possible
            to delete conceptual rows which are either `notReady',
            `notInService' or `active'.)  If the operation succeeds,
            then all instances associated with the conceptual row are
            immediately removed."


    SYNTAX       INTEGER {
                     -- the following two values are states:
                     -- these values may be read or written
                     active(1),
                     notInService(2),




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                     -- the following value is a state:
                     -- this value may be read, but not written
                     notReady(3),

                     -- the following three values are
                     -- actions: these values may be written,
                     --   but are never read
                     createAndGo(4),
                     createAndWait(5),
                     destroy(6)
                 }


TimeStamp ::= TEXTUAL-CONVENTION
    STATUS       current
    DESCRIPTION
            "The value of the sysUpTime object at which a specific
            occurrence happened.  The specific occurrence must be
            defined in the description of any object defined using this
            type."
    SYNTAX       TimeTicks


TimeInterval ::= TEXTUAL-CONVENTION
    STATUS       current
    DESCRIPTION
            "A period of time, measured in units of 0.01 seconds."
    SYNTAX       INTEGER (0..2147483647)


DateAndTime ::= TEXTUAL-CONVENTION
    DISPLAY-HINT "2d-1d-1d,1d:1d:1d.1d,1a1d:1d"
    STATUS       current
    DESCRIPTION
            "A date-time specification.

            field  octets  contents                  range
            -----  ------  --------                  -----
              1      1-2   year                      0..65536
              2       3    month                     1..12
              3       4    day                       1..31
              4       5    hour                      0..23
              5       6    minutes                   0..59
              6       7    seconds                   0..60
                           (use 60 for leap-second)
              7       8    deci-seconds              0..9
              8       9    direction from UTC        '+' / '-'
              9      10    hours from UTC            0..11



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RFC 1903             Textual Conventions for SNMPv2         January 1996


             10      11    minutes from UTC          0..59

            For example, Tuesday May 26, 1992 at 1:30:15 PM EDT would be
            displayed as:

                             1992-5-26,13:30:15.0,-4:0

            Note that if only local time is known, then timezone
            information (fields 8-10) is not present."
    SYNTAX       OCTET STRING (SIZE (8 | 11))