rfc1695.txt

著名的RFC文档,其中有一些文档是已经翻译成中文的的.

                            |   AAL5         |
                            |________________|
                            |                |
                            | Prop. Virtual  |
                            |  Interface     |
                            |________________|

               Figure 5 : AAL5 Entity's Interface Stack in a Switch

8.2.  Managing AAL5 in a Host

   Managing AAL5 in a host involves managing the AAL5 sublayer interface
   as shown in Figures 6 and 7.  The AAL5 sublayer is stacked directly
   over the ATM sublayer.  The ifTable is applied to the AAL5 sublayer
   as defined in Section 8.3.

                        ___________________________
                        |                         |
                        |     =============       |
                        |     |    AAL5   |       |
                        |     |   Entity  |       |
                        |     =============       |
                        |     |   ATM     |       |
                        |     |  Entity   |       |
                        |     =============       |
                        |___________|_____________|
                                    |
                                  __|__ ATM UNI
                                    |
                                    |
                                    v

                Figure 6 : Model of an AAL5 Entity in a Host


                            __________________
                            |                |
                            |   AAL5         |
                            |________________|
                            |                |
                            |   ATM Layer    |
                            |________________|
                            |                |
                            |  Physical Layer|
                            |________________|




Ahmed & Tesink                                                 [Page 12]

RFC 1695                 ATM Management Objects              August 1994


                 Figure 7 : AAL5 Entity's Interface Stack in a Host

8.3.  Support of AAL5 by ifTable

   The AAL5 entity in an ATM device (e.g., switch or host) is managed
   using the ifTable.  There are additional counters specified for AAL5
   than those specified in the ATM B-ICI document [10].  Specific
   interpretations of ifTable for the AAL5 CPCS layer are as follows.

          Object   Use for AAL5 CPCS layer entity
          ======   ==============================

          ifIndex  Each AAL5 entity is represented by an ifEntry.

          ifDescr  Description of the AAL5 entity.

          ifType   The value that is allocated for AAL5 is 49.

          ifMtu    Set to the largest PDU size for the
                   AAL5 CPCS layer that can be processed
                   by the AAL5 entity.

          ifSpeed  Set to 0.

          ifPhysAddress   An octet string of zero length.

          ifAdminStatus   See [5].

          ifOperStatus    Assumes the value down(2) if the AAL5 or
                   any layer below that layer is down.

          ifLastChange    See [5].

          ifInOctets      The number of received AAL5 CPCS PDU octets.

          ifOutOctets     The number of AAL5 CPCS PDU octets
                   transmitted.

          ifInUcastPkts   The number of received AAL5 CPCS PDUs passed
                   to a higher-layer.

          ifOutUcastPkts  The number of AAL5 CPCS PDUs received from a
                   higher-layer for transmission.
                   [Note:  The number of AAL5 PDUs actually
                   transmitted is the number received from a
                   higher-layer for transmission minus any which
                   are counted by ifOutErrors and ifOutDiscards.]




Ahmed & Tesink                                                 [Page 13]

RFC 1695                 ATM Management Objects              August 1994


          ifInErrors      Number of errored AAL5 CPCS PDUs received.
                   The types of errors counted include  CRC-32 errors,
                   SAR time-out errors, and oversized SDU errors.

          ifInUnknownProtos Set to 0.

          ifInDiscards    Number of received AAL5 CPCS PDUs discarded.
                   Possible reason may be input buffer overflow.

          ifOutErrors     Number of AAL5 CPCS PDUs that could not
                   be transmitted due to errors.

          ifOutDiscards   Number of AAL5 CPCS PDUs received for
                   transmission that are discarded.
                   Possible reason may be output buffer
                   overflow.

          ifInMulticastPkts  Set to 0.

          ifInBroadcastPkts  Set to 0.

          ifOutMulticastPkts Set to 0.

          ifOutBroadcastPkts Set to 0.

          ifName   Textual name (unique on this system) of the
                   AAL5 entity or an octet string of zero length.

          ifHighSpeed       Set to 0.

          ifConnectorPresent Set to false (2).

          ifPromiscuousMode Set to false(2).

          ifLinkUpDownTrapEnable     Default is disabled (2).

8.4.  Support of Proprietary Virtual Interface by ifTable

   Specific interpretations of ifTable for the proprietary virtual,
   internal interface associated with an AAL5 entity in an ATM switch
   are as follows.

          Object   Use for proprietary virtual, internal interface
                   associated with AAL entities
          ======   ===============================================

          ifIndex  Each proprietary virtual, internal interface
                   associated with AAL entities is represented by an



Ahmed & Tesink                                                 [Page 14]

RFC 1695                 ATM Management Objects              August 1994


                   ifEntry.

          ifDescr  Description of the proprietary virtual, internal
                   interface associated with AAL entities.

          ifType   The value that is allocated for proprietary
                   virtual, internal interface is 53.

          ifSpeed  See [5].  Set to 0 if the speed is not
                   known.

          ifPhysAddress   See [5]. An octet string of zero length
                   if no address is used for this interface.

          ifAdminStatus   See [5].

          ifOperStatus    See [5].

          ifLastChange    See [5].

          ifName   Textual name (unique on this system) of the
                   interface or an octet string of zero length.

          ifHighSpeed     See [5]. Set to 0 if the speed is not known.

          ifConnectorPresent  Set to false (2).

          ifLinkUpDownTrapEnable     Default is disabled (2).

8.5.  AAL5 Connection Performance Statistics Group

   An AAL5 connection table is used to provide AAL5 performance
   information for each AAL5 virtual connection that is terminated at
   the AAL5 entity contained within an ATM switch or host.

9.  ILMI MIB and the ATM Managed Objects

   The ILMI MIB is specified by the ATM Forum in UNI specification [9],
   to manage local ATM UNIs.  The support of the ATM management
   functions by the ILMI MIB and those contained in this memo are
   compared in Table 1.  In this table, "yes" in the "ILMI MIB"  column
   indicates that the management functions are supported by the ILMI
   MIB.  The MIB groups in the "This memo" column are the groups listed
   in Section 5.2.

   For that subset of management information which the ILMI MIB and this
   memo have in common, every effort has been made to retain identical
   semantics and syntax, even though the MIB objects are identified



Ahmed & Tesink                                                 [Page 15]

RFC 1695                 ATM Management Objects              August 1994


   using different OBJECT IDENTIFIERs.

                       Table 1 - Structuring of ATM Managed Objects

          ______________________________________________________________
                        |                                 |This   |ILMI|
          ATM Mgmt.Inf. |ATM Managed Objects              |memo   |MIB |
          ______________|_________________________________|_______|____|

          Local Interface Information:
          _____________________________________________________________
          ATM interface:| (1) port identifier             |ATM MIB|    |
          physical layer| (2) physical transmission types |  gr.1*|yes*|
          configuration | (3) operational status          |MIB II |    |
                        | (4) administrative status       |       |    |
                        | (5) last change status          |       |    |
          _____________________________________________________________
          ATM interface:| (1) active VPI/VCI fields       |ATM MIB|    |
          cell layer    | (2) maximum number of VPCs/VCCs |  gr.1 |yes |
          configuration | (3) configured VPCs/VCCs        |       | ** |
                        | (4) ILMI VPI/VCI values         |       |    |
                        | (5) ATM address type            |       |    |
                        | (6) ATM administrative address  |       |    |
          _____________________________________________________________
          ATM interface:|(1) received/transmitted cells   |       |    |
          cell layer    |(2) cells with HEC error         |MIB II |yes |
          performance   |(3) cell header validation errors|       |    |
          _____________________________________________________________
          ATM interface:|(1)DS3 PLCP severely errored     |ATM MIB|    |
          PLCP & TC     |   framing seconds               | gr.2,3|    |
          layer         |(2)DS3 PLCP unavailable seconds  |       |no  |
          performance   |(3)DS3 PLCP alarm state          |       |    |
                        |(4)out of cell delineation events|       |    |
                        |(5)TC alarm state                |       |    |
          _____________________________________________________________
          VP/VC link:   |(1)VPI or VPI/VCI value          |ATM MIB|    |
          configuration |(2)VCL or VPL operational status |  gr. 4|yes |
                        |(3)VCL/VPL administrative status |       |*** |
                        |(4)VCL/VPL last change status    |       |    |
                        |(5)transmit/receive traffic/QoS  |       |    |
                        |   parameters                    |       |    |
                        |(6)AAL type                      |       |    |
                        |(7)transmit/receive AAL5 SDU size|       |    |
                        |(8)AAL5 encapsulation type       |       |    |
          _____________________________________________________________






Ahmed & Tesink                                                 [Page 16]

RFC 1695                 ATM Management Objects              August 1994


          _____________________________________________________________
          VP/VC         |(1)cross-connect identifier      |       |    |
          Cross-connect:|(2)port identifier of one        |       |    |
          configuration |   end                           |       |    |
                        |(3)port identifier of the other  |ATM MIB|    |
                        |   end                           |  gr. 5|no  |
                        |(4)VPI or VPI/VCI value          |       |    |
                        |   of one end                    |       |    |
                        |(5)VPI or VPI/VCI value of       |       |    |
                        |   the other end                 |       |    |
                        |(6)VC/VP cross-connect           |       |    |
                        |   operational status            |       |    |
                        |(7)VC/VP cross-connect           |       |    |
                        |   administrative status         |       |    |
                        |(8)VC/VP last change status      |       |    |
          _____________________________________________________________
          VCC AAL5 CPCS |(1)PDUs discarded for CRC errors |ATM MIB|    |
          layer:        |(2)PDUs discarded due to         |  gr.6 |    |
          performance   |   reassembly time out           |       |no  |
                        |(3)PDUs discarded due to large   |       |    |
                        |   SDUs                          |       |    |
          _____________________________________________________________
          AAL5 entity:  |(1)received/transmitted PDUs     |       |    |
                        |(2)PDUs discarded due to         |       |    |
                        |   protocol errors               |MIB II |no  |
                        |(3)a set of configuration/state  |       |    |
                        |   parameters                    |       |    |
          _____________________________________________________________

          *The operational, administrative, and last change status of
          the ATM interface and the physical transmission type shall be
          supported by the interface table in MIB II (RFC 1213, RFC
          1573).  ILMI does not contain the administrative and last
          change status of the ATM interface.