rfc1592.txt

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         assigned in the RESPONSE packet in the error_index field.
     o   a requested timeout.
         If a zero value is specified, then the agent uses the timeout
         value specified in the DPI OPEN request.
         If you want a shorter or longer timeout value for this specific
         sub-tree, then you specify it here.  The agent has a maximum
         timeout it will allow in this field.  The agent will use this
         value (or its maximum) to await a response to requests for this
         sub-tree.
     o   an indication as to whether the sub-agent wishes to handle MIB
         view selection (SNMPv1 community string authentication)
         in subsequent GET, GETNEXT or SET, COMMIT, UNDO requests.  Not
         all DPI capable agents need to support this feature, but they
         must at least recognize this indication and give an appropriate



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RFC 1592                        SNMP-DPI                      March 1994


         response if they do not support it.
     o   an indication as to whether the sub-agent wishes to handle the
         GETBULK itself.  If not, then the agent will translate a
         GETBULK into multiple GETNEXT requests.
         Not all DPI capable agents need to support this feature.  They
         may opt to always translate a GETBULK into multiple GETNEXT
         requests.  In this case the agent will send the appropriate
         RESPONSE to indicate this.
     o   the group ID (sub-tree) to be registered (with trailing dot).
         The group ID is represented in the selected character set as
         specified in DPI OPEN packet.

   The agent will respond with an SNMP DPI RESPONSE packet indicating
   registration error or success.  The packet ID of the response will be
   the same as that for the REGISTER request to which this is a
   response.

   The group ID will be the same as that specified in the REGISTER
   request.  There will be no instance returned (e.g. NULL string for
   instance ID).  The value will be an SNMP_TYPE_NULL value with a zero
   length.






























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RFC 1592                        SNMP-DPI                      March 1994


     +-----------------------------------------------------------------+
     | Table 7. Layout SNMP DPI REGISTER packet                        |
     +------------+----------------------------------------------------+
     | OFFSET     | FIELD                                              |
     +------------+----------------------------------------------------+
     | 0          | packet length to follow (MSB to LSB)               |
     +------------+----------------------------------------------------+
     | 2          | protocol major version                             |
     +------------+----------------------------------------------------+
     | 3          | protocol minor version                             |
     +------------+----------------------------------------------------+
     | 4          | protocol release                                   |
     +------------+----------------------------------------------------+
     | 5          | packet id (MSB to LSB)                             |
     +------------+----------------------------------------------------+
     | 7          | packet type = SNMP_DPI_REGISTER                    |
     +------------+----------------------------------------------------+
     | 8          | requested priority (MSB to LSB)                    |
     +------------+----------------------------------------------------+
     | 12         | timeout in seconds (MSB to LSB)                    |
     +------------+----------------------------------------------------+
     | 14         | view selection (0 = you (agent) do, 1 = I do)      |
     +------------+----------------------------------------------------+
     | 15         | getbulk selection (0=use GetNext, 1=use GetBulk)   |
     +------------+----------------------------------------------------+
     | 16         | null terminated group ID (with trailing dot)       |
     +------------+----------------------------------------------------+
     | NOTE:                                                           |
     |                                                                 |
     | o   group ID string uses selected character set                 |
     +-----------------------------------------------------------------+

3.2.6  UNREGISTER

   In order to unregister a branch in the MIB tree, an SNMP sub-agent
   sends an SNMP DPI UNREGISTER packet to the agent.

   Such a packet contains the standard SNMP DPI header plus UNREGISTER
   specific data: a null terminated string (represented in the selected
   character set) representing the group ID in ASN.1 dotted notation and
   an indication as to the reason for the unregister (see table 14).

   The agent will respond with an SNMP DPI RESPONSE packet indicating
   error or success.  The packet ID of the response will be the same as
   that for the UNREGISTER request to which this is a response.

   The group ID will be the same as that specified in the UNREGISTER
   request.  There will be no instance returned (e.g. NULL string for



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RFC 1592                        SNMP-DPI                      March 1994


   instance ID).  The value will be an SNMP_TYPE_NULL value with a zero
   length.

     +-----------------------------------------------------------------+
     | Table 8. Layout SNMP DPI UNREGISTER packet                      |
     +------------+----------------------------------------------------+
     | OFFSET     | FIELD                                              |
     +------------+----------------------------------------------------+
     | 0          | packet length to follow (MSB to LSB)               |
     +------------+----------------------------------------------------+
     | 2          | protocol major version                             |
     +------------+----------------------------------------------------+
     | 3          | protocol minor version                             |
     +------------+----------------------------------------------------+
     | 4          | protocol release                                   |
     +------------+----------------------------------------------------+
     | 5          | packet id (MSB to LSB)                             |
     +------------+----------------------------------------------------+
     | 7          | packet type = SNMP_DPI_UNREGISTER                  |
     +------------+----------------------------------------------------+
     | 8          | reason code                                        |
     +------------+----------------------------------------------------+
     | 9          | null terminated group ID (with trailing dot)       |
     +------------+----------------------------------------------------+
     | NOTE:                                                           |
     |                                                                 |
     | o   group ID string uses selected character set                 |
     +-----------------------------------------------------------------+

3.2.7  GET

   When the SNMP agent receives a PDU containing an SNMP GET request for
   a variable that resides in a sub-tree registered by a sub-agent, it
   passes an SNMP DPI GET packet to the sub-agent.

   Such a packet contains the standard SNMP DPI header plus GET specific
   data:

     o   the community name used in the SNMP PDU.  The length is zero
         unless view handling was selected by the sub-agent.  The length
         is also zero if the SNMP PDU was not in SNMPv1 format.
     o   per varBind two null terminated strings (in the selected
         character set) representing the group and instance ID in ASN.1
         dotted notation.







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RFC 1592                        SNMP-DPI                      March 1994


     +-----------------------------------------------------------------+
     | Table 9. Layout SNMP DPI GET packet                             |
     +------------+----------------------------------------------------+
     | OFFSET     | FIELD                                              |
     +------------+----------------------------------------------------+
     | 0          | packet length to follow (MSB to LSB)               |
     +------------+----------------------------------------------------+
     | 2          | protocol major version                             |
     +------------+----------------------------------------------------+
     | 3          | protocol minor version                             |
     +------------+----------------------------------------------------+
     | 4          | protocol release                                   |
     +------------+----------------------------------------------------+
     | 5          | packet id (MSB to LSB)                             |
     +------------+----------------------------------------------------+
     | 7          | packet type = SNMP_DPI_GET                         |
     +------------+----------------------------------------------------+
     | 8          | community name length (MSB to LSB)                 |
     +------------+----------------------------------------------------+
     | 10         | community name (if any)                            |
     +------------+----------------------------------------------------+
     | 10+L1      | null terminated group ID (with trailing dot)       |
     +------------+----------------------------------------------------+
     | 10+L2      | null terminated instance ID (no trailing dot)      |
     +------------+----------------------------------------------------+
     | 10+L3      | optionally more varBinds (group/instance ID pairs) |
     +------------+----------------------------------------------------+
     | NOTE:                                                           |
     |                                                                 |
     | o   L1 = length of community name                               |
     | o   L2 = L1 +  strlen(group ID) + 1                             |
     | o   L3 = L2 +  strlen(instance ID) + 1                          |
     | o   group and instance ID strings use selected character set    |
     +-----------------------------------------------------------------+

3.2.8  GETNEXT

   When the SNMP agent receives a PDU containing an SNMP GETNEXT request
   for a variable for which a sub-agent may be authoritative, it passes
   an SNMP DPI GETNEXT packet to the sub-agent.

   Such a packet contains the standard SNMP DPI header plus GETNEXT
   specific data:

     o   the community name used in the SNMP PDU.  The length is zero
         unless view handling was selected by the sub-agent.  The length
         is also zero if the SNMP PDU was not in SNMPv1 format.
     o   per varBind two null terminated strings (in the selected



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RFC 1592                        SNMP-DPI                      March 1994


         character set) representing the group and instance ID in ASN.1
         dotted notation.

     +-----------------------------------------------------------------+
     | Table 10. Layout SNMP DPI GETNEXT packet                        |
     +------------+----------------------------------------------------+
     | OFFSET     | FIELD                                              |
     +------------+----------------------------------------------------+
     | 0          | packet length to follow (MSB to LSB)               |
     +------------+----------------------------------------------------+
     | 2          | protocol major version                             |
     +------------+----------------------------------------------------+
     | 3          | protocol minor version                             |
     +------------+----------------------------------------------------+
     | 4          | protocol release                                   |
     +------------+----------------------------------------------------+
     | 5          | packet id (MSB to LSB)                             |
     +------------+----------------------------------------------------+
     | 7          | packet type = SNMP_DPI_GETNEXT                     |
     +------------+----------------------------------------------------+
     | 8          | community name length (MSB to LSB)                 |
     +------------+----------------------------------------------------+
     | 10         | community name                                     |
     +------------+----------------------------------------------------+
     | 10+L1      | null terminated group ID (with trailing dot)       |
     +------