rfc2955.txt

著名的RFC文档,其中有一些文档是已经翻译成中文的的.

   atmVcCrossConnectTable row for the connection.

   In the case of an inter-worked connection, the
   atmVclCrossConnectIdentifier object is set to zero.  Instead, the
   frAtmIwfVclCrossConnectIdentifier object in the frAtmIwfVclEntry is
   set to the index of the applicable FR/ATM IWF cross-connect table
   row.






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RFC 2955           FR to ATM Service Interworking MIB       October 2000


   Note that the frAtmIwfVclCrossConnectIdentifier object is defined not
   in the ATM MIB but in Section 5 of this MIB.  Specifically, the
   object is defined as a column object in a table that AUGMENTs the ATM
   MIB VCL table.

   The ATM VCL cross-connect table (atmVcCrossConnectTable) does not
   contain an entry for the inter-worked connection.

   Note that the atmVclCrossConnectIdentifier and
   frAtmIwfVclCrossConnectIdentifier objects are set by the system as a
   side-effect of cross-connect establishment.  Consequently, these
   objects are read-only.

3.3.4.  IF MIB

   The ifIndex defined in the IF MIB [22] identifies the specific frame
   relay and ATM endpoint interfaces.  The values frAtmIwfConnAtmPort
   and frAtmIwfConnFrPort are used in this MIB as components in the
   index list for the frAtmIwfConnectionTable rows.

3.4.  Point to Multipoint Considerations

   This MIB supports IWF implementations providing point-to-multipoint
   functionality. All rows of the cross-connect table indexed by the
   same frAtmIwfConnIndex MUST utilize the same
   frAtmIwfConnectionDescriptor value.

   A group of cross-connect table entries indexed by the same
   frAtmIwfConnIndex value MUST agree on which service the multipoint
   operation is offered. Two cases are possible:

   (1) Many frame relay PVCs cross-connected to one ATM PVC, or

   (2) One frame relay PVC cross-connected to many ATM PVCs

3.5.  Theory of Operation

3.5.1.  Creation Process

   Multiple steps are required to create a frame relay to ATM cross-
   connection.  First, rows must be created in the following tables:

   (1) The Frame Relay Service MIB frPVCEndptTable

   (2) The ATM MIB atmVclTable

   (3) The FR/ATM Service IWF MIB frAtmIwfConnectionDescriptorTable




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   (4) The FR/ATM Service IWF MIB frAtmIwfConnectionTable

   Second, the newly created rows are cross-linked.

   Finally, the administrative and operational status objects are set to
   'up(1)'.

   A step-by-step example is provided to illustrate the creation
   process.  In this example, the term "Manager" refers to a network
   management system that issues SNMP protocol actions to an "Agent".
   The agent is integrated with the system that implements the frame
   relay to ATM service IWF.  In this example, the following cross-
   connection is created:

                  +-----------------------------------+
   +---------+    |       FR/ATM PVC Service IWF      |
   | Frame   |    |   ------------------------------  |    +-----------+
   | Relay   |  +--------> frAtmIwfConnIndex K <--------+  |   ATM     |
   |Endpoint |  | |               V                   | |  | Endpoint  |
   | ------- |  | |               |                   | |  | --------- |
   | DLCI X  |  | |  +------------+                   | |  |VPI.VCI Q.R|
   |  on     |<-+ |  |                                | +->|    on     |
   |ifIndex Y|    |  V                                |    | ifIndex S |
   +---------+    |frAtmIwfConnectionDescriptorIndex L|    +-----------+
                  +-----------------------------------+

   Step 1 - Create the frame relay PVC endpoint

   a) Manager requests creation of a new row in the frPVCEndptTable

   b) Agent receives management request to create a row in
      frPVCEndptTable for the frame relay side

   c) A new row is created in frPVCEndptTable as follows:

      -  frPVCEndptConnectIdentifier initialized to zero

      -  frPVCEndptAtmIwfConnIndex initialized to zero

      -  remaining row objects initialized as needed for DLCI X on
         ifIndex Y

   Step 2 - Create the ATM PVC endpoint

   a) Agent receives management request to create a row in atmVclTable
      for the ATM side





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RFC 2955           FR to ATM Service Interworking MIB       October 2000


   b) A new row is created in atmVclTable and frAtmIwfVclTable (the
      AUGMENT to the atmVclTable) as follows:

      -  atmVclCrossConnectIdentifier initialized to zero

      -  frAtmIwfVclCrossConnectIdentifier initialized to zero

      -  atmVclConnKind initialized to pvc(1)

      -  remaining row objects initialized as needed for VPI.VCI Q.R on
         ifIndex S

   Step 3 - Create the FR/ATM connection descriptor

   a) If an existing connection descriptor is appropriate for the new
      connection, go to Step 4 using the selected connection descriptor
      index value L

   b) Manager requests a new connection descriptor index value by
      reading frAtmIwfConnectionDescriptorIndexNext from the agent

   c) Agent receives GET request for
      frAtmIwfConnectionDescriptorIndexNext and responds with the next
      available value L

   d) Manager requests a new connection descriptor row entry using the
      value L as the index

   e) Agent receives SET request to create the
      frAtmIwfConnectionDescriptorTable row entry causes the system to
      create a row in the table.

   Step 4 - Create the FR/ATM cross-connect

   a) Manager requests a new cross-connect index value by reading
      frAtmIwfConnIndexNext from the agent

   b) Agent receives GET request for frAtmIwfConnIndexNext and responds
      with the next available value K

   c) Manager requests a new cross-connect row entry using the value K
      as the index

   d) Agent receives SET request to create the frAtmIwfConnectionTable
      row entry (note: the frame relay and ATM PVC endpoints MUST exist
      and be specified as part of the index fields for the row
      'K.S.Q.R.Y.X')




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RFC 2955           FR to ATM Service Interworking MIB       October 2000


   e) System creates a row in frAtmIwfConnectionTable for the following
      indices:

      -  frAtmIwfConnIndex of K

      -  frAtmIwfConnAtmPort of S

      -  frAtmIwfConnVpi of Q

      -  frAtmIwfConnVci of R

      -  frAtmIwfConnFrPort of Y

      -  frAtmIwfConnDlci of X

      -  frAtmIwfConnectionDescriptor of L

   Step 5 - The system sets the frame relay PVC endpoint and ATM VCL
   endpoint to point to the FR/ATM cross-connect row (as a side-effect
   of Step 4).

   a) System sets frPVCEndptAtmIwfConnIndex to K

   b) System sets frAtmIwfVclCrossConnectIdentifier to K

   Step 6 - Manager signals activation by issuing a SET for the
   frAtmIwfConnAdminStatus object using the value of 'up(1)'

   Step 7 - Agent receives SET request for frAtmIwfConnAdminStatus and
   executes internal system mechanisms to activate each PVC segment and
   the IWF cross-connect. The successful activation permits the agent to
   respond with 'up(1)' when a GET request is received for the following
   fields:

      -  frAtmIwfConnAtm2FrOperStatus

      -  frAtmIwfConnFr2AtmOperStatus

      -  atmVclOperStatus (Note: there is no comparable FRS MIB object)

3.5.2.  Destruction Process

   Destruction of the frame relay to ATM cross-connection is initiated
   by the network management system.  The agent's processing of the
   request stimulates implementation-specific system clean-up actions.
   Following removal of the row in the cross-connection table, the
   frAtmIwfVclCrossConnectIdentifier in the frAtmIwfVclTable (AUGMENT of




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   the ATM MIB endpoint table) and frPVCEndptAtmIwfConnIndex in the
   Frame Relay Service MIB endpoint table are both re-initialized to
   zero.

   A step-by-step example is provided to illustrate the destruction
   process.

   Step 1 - Manager requests destruction of an existing row in the
   frAtmIwfConnectionTable by setting frAtmIwfConnRowStatus to
   destroy(6)

   Step 2 - Agent receives the SET request and performs implementation-
   specific system clean-up actions for the cross-connection row

   Step 3 - System updates the relevant cross connect information for
   the frame relay PVC endpoint by setting frPVCEndptAtmIwfConnIndex to
   0

   Step 4 - System updates the relevant cross connect information for
   the ATM PVC endpoint as follows:

   a) System sets frAtmIwfVclCrossConnectIdentifier to 0

   b) System sets atmVclOperStatus to 'down(2)' (Note: there is no
      comparable FRS MIB object)

   Following the destruction of the FR/ATM cross-connection entry, the
   manager MAY set the frPVCConnectRowStatus and/or atmVclRowStatus to
   destroy(6) the associated endpoint entries.

3.5.3.  Modification Process

   At the discretion of the agent, a FR/ATM cross-connect may be
   reconfigured by adding and/or deleting leafs to/from the IWF topology
   as per the FR/ATM IWF cross-connect creation/destruction procedures.
   Reconfiguration of traffic/service category parameter values requires
   release of the FR/ATM IWF cross-connect before those parameter values
   may be changed for individual frame relay or ATM endpoint segments.

4.  Object Definitions

FR-ATM-PVC-SERVICE-IWF-MIB DEFINITIONS ::= BEGIN

IMPORTS
              MODULE-IDENTITY, OBJECT-TYPE,
              NOTIFICATION-TYPE,
              mib-2, Integer32, Counter32             FROM SNMPv2-SMI




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RFC 2955           FR to ATM Service Interworking MIB       October 2000


              RowStatus, TimeStamp                    FROM SNMPv2-TC

              MODULE-COMPLIANCE, OBJECT-GROUP,
              NOTIFICATION-GROUP                      FROM SNMPv2-CONF

              AtmVpIdentifier, AtmVcIdentifier        FROM ATM-TC-MIB

              atmVclEntry                             FROM ATM-MIB

              InterfaceIndex                          FROM IF-MIB;

         frAtmIwfMIB MODULE-IDENTITY
             LAST-UPDATED "200009280000Z" -- September 28, 2000
             ORGANIZATION "IETF Frame Relay Service MIB Working Group"
             CONTACT-INFO
                 "WG Charter:
                    http://www.ietf.org/html.charters/frnetmib-charter
                  WG-email:
                    [e-mail]
                  Subscribe:
                    [e-mail]
                  Email Archive:
                    ftp://ftp.ietf.org/ietf-mail-archive/frnetmib

                  Chair:      Andy Malis
                              Vivace Networks, Inc.