rfc2670.txt

著名的RFC文档,其中有一些文档是已经翻译成中文的的.

   docsIfCmtsCmTable via a MAC address (of the CM) interface.

3.2.  Relationship to the Interfaces MIB

   This section clarifies the relationship of this MIB to the Interfaces
   MIB [17].  Several areas of correlation are addressed in the
   following subsections.  The implementor is referred to the Interfaces
   MIB document in order to understand the general intent of these
   areas.

3.2.1.  Layering Model

   An instance of ifEntry exists for each RF Downstream interface, for
   each RF Upstream interface, and for each RF MAC layer.  The
   ifStackTable [17] MUST be implemented to identify relationships among
   sub-interfaces.








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RFC 2670                DOCSIS RF Interface MIB              August 1999


   The following example illustrates a MAC interface with one downstream
   and two upstream channels.

                               | <== to network layer
                 +-------------+--------------+
                 |           RF MAC           |
                 +----+---------+-----------+-+
                      |         |           |
            +---------+---+ +---+-------+ +-+---------+
            | Downstream1 | | Upstream1 | | Upstream2 |
            +-------------+ +-----------+ +-----------+

   As can be seen from this example, the RF MAC interface is layered on
   top of the downstream and upstream interfaces.

   In this example, the assignment of index values could be as follows:

      ifIndex ifType                   Description

      1    docsCableMaclayer(127)   CATV MAC Layer
      2    docsCableDownstream(128) CATV Downstream interface
      3    docsCableUpstream(129)   CATV Upstream interface
      4    docsCableUpstream(129)   CATV Upstream interface

      The corresponding ifStack entries would then be:

           | IfStackHigherLayer | ifStackLowerLayer |
           |         0          |         1         |
           |         1          |         2         |
           |         1          |         3         |
           |         1          |         4         |
           |         2          |         0         |
           |         3          |         0         |
           |         4          |         0         |

   The same interface model can also be used in Telephony or Telco
   Return systems.  A pure Telco Return system (Cable Modem as well as
   Cable Modem Termination System) would not have upstream, but only
   downstream cable channels.  Systems supporting both Telco Return and
   cable upstream channels can use the above model without modification.

   Telco Return Upstream channel(s) are handled by the appropriate MIBs,
   such as PPP or Modem MIBs.

3.2.2.  Virtual Circuits

   This medium does not support virtual circuits and this area is not
   applicable to this MIB.



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RFC 2670                DOCSIS RF Interface MIB              August 1999


3.2.3.  ifTestTable

   The ifTestTable is not supported by this MIB.

3.2.4.  ifRcvAddressTable

   The ifRcvAddressTable is not supported by this MIB.

3.2.5.  ifEntry

   This section documents only the differences from the requirements
   specified in the Interfaces MIB.  See that MIB for columns omitted
   from the descriptions below.

3.2.5.1.  ifEntry for Downstream interfaces

   The ifEntry for Downstream interfaces supports the
   ifGeneralInformationGroup and the ifPacketGroup of the Interfaces
   MIB.  This is an output only interface at the CMTS and all input
   status counters - ifIn* - will return zero.  This is an input only
   interface at the CM and all output status counters - ifOut* - will
   return zero.

3.2.5.1.1.  ifEntry for Downstream interfaces in Cable Modem Termination
            Systems

   ifTable           Comments
   ==============    ===========================================
   ifIndex           Each RF Cable Downstream interface is represented
                     by an ifEntry.

   ifType            The IANA value of docsCableDownstream(128).

   ifSpeed           Return the speed of this downstream channel.
                     The returned value the raw bandwidth in bits/s
                     of this interface. This is the symbol rate
                     multiplied with the number of bits per symbol.

   ifPhysAddress     Return an empty string.

   ifAdminStatus     The administrative status of this interface.

   ifOperStatus      The current operational status of this interface.

   ifMtu             The size of the largest frame which can be
                     sent on this interface, specified in octets.
                     The value includes the length of the MAC header.




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RFC 2670                DOCSIS RF Interface MIB              August 1999


   ifInOctets        Return zero.

   ifInUcastPkts     Return zero.

   ifInMulticastPkts Return zero.

   ifInBroadcastPkts Return zero.

   ifInDiscards      Return zero.

   ifInErrors        Return zero.

   ifInUnknownProtos Return zero.

   ifOutOctets       The total number of octets transmitted on this
                     interface. This includes MAC packets as well as
                     data packets, and includes the length of the MAC
                     header.

   ifOutUcastPkts    The number of Unicast packets transmitted on this
                     interface. This includes MAC packets as well as
                     data packets.

   ifOutMulticastPkts
                     Return the number of Multicast packets transmitted
                     on this interface.
                     This includes MAC packets as well as data packets.

   ifOutBroadcastPkts
                     Return the number of broadcast packets transmitted
                     on this interface.
                     This includes MAC packets as well as data packets.

   ifOutDiscards     The total number of outbound packets which
                     were discarded. Possible reasons are:
                     buffer shortage.

   ifOutErrors       The number of packets which could not be
                     transmitted due to errors.

   ifPromiscuousMode Return false.










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RFC 2670                DOCSIS RF Interface MIB              August 1999


3.2.5.1.2.  ifEntry for Downstream interfaces in Cable Modems

   ifTable           Comments
   ==============    ===========================================
   ifIndex           Each RF Cable Downstream interface is represented
                     by an ifEntry.

   ifType            The IANA value of docsCableDownstream(128).

   ifSpeed           Return the speed of this downstream channel.
                     The returned value the raw bandwidth in bits/s
                     of this interface. This is the symbol rate
                     multiplied with the number of bits per symbol.

   ifPhysAddress     Return an empty string.

   ifAdminStatus     The administrative status of this interface.

   ifOperStatus      The current operational status of this interface.

   ifMtu             The size of the largest frame which can be
                     received from this interface, specified in octets.
                     The value includes the length of the MAC header.

   ifInOctets        The total number of octets received on this
                     interface. This includes data packets as well as
                     MAC layer packets, and includes the length of the
                     MAC header.

   ifInUcastPkts     The number of Unicast packets received on this
                     interface. This includes data packets as well as
                     MAC layer packets.

   ifInMulticastPkts Return the number of Multicast packets received
                     on this interface. This includes data packets as
                     well as MAC layer packets.

   ifInBroadcastPkts Return the number of Broadcast packets received
                     on this interface. This includes data packets
                     as well as MAC layer packets.

   ifInDiscards      The total number of received packets which have
                     been discarded.
                     The possible reasons are: buffer shortage.

   ifInErrors        The number of inbound packets that contained
                     errors preventing them from being deliverable
                     to higher layers.



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RFC 2670                DOCSIS RF Interface MIB              August 1999


                     Possible reasons are: MAC FCS error.

   ifInUnknownProtos The number of frames with an unknown packet type.
                     These are MAC frames with an unknown packet type.

   ifOutOctets       Return zero.

   ifOutUcastPkts    Return zero.

   ifOutMulticastPkts
                     Return zero.

   ifOutBroadcastPkts
                     Return zero.

   ifOutDiscards     Return zero.

   ifOutErrors       Return zero.

   ifPromiscuousMode Refer to the Interfaces MIB.

3.2.5.2.  ifEntry for Upstream interfaces

   The ifEntry for Upstream interfaces supports the
   ifGeneralInformationGroup and the ifPacketGroup of the Interfaces
   MIB.  This is an input only interface at the CMTS and all output
   status counters - ifOut* - will return zero.  This is an output only
   interface at the CM and all input status counters - ifIn* - will
   return zero.

3.2.5.2.1.  ifEntry for Upstream interfaces in Cable Modem Termination
            Systems

   ifTable           Comments
   ==============    ===========================================
   ifIndex           Each RF Cable Upstream interface is represented
                     by an ifEntry.

   ifType            The IANA value of docsCableUpstream(129).

   ifSpeed           Return the speed of this upstream channel.
                     The returned value is the raw bandwidth
                     in bits/s of this interface, regarding the
                     highest speed modulation profile that is
                     defined. This is the symbol rate multiplied
                     with the number of bits per symbol for this
                     modulation profile.




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RFC 2670                DOCSIS RF Interface MIB              August 1999


   ifPhysAddress     Return an empty string.

   ifAdminStatus     The administrative status of this interface.

   ifOperStatus      The current operational status of this interface.

   ifMtu             The size of the largest frame which can be
                     received on this interface, specified in octets.
                     The value includes the length of the MAC header.

   ifInOctets        The total number of octets received on this
                     interface. This includes data packets as well as
                     MAC layer packets, and includes the length of the
                     MAC header.

   ifInUcastPkts     The number of Unicast packets received on this
                     interface. This includes data packets as well as
                     MAC layer packets.

   ifInMulticastPkts Return the number of Multicast packets received
                     on this interface. This includes data packets as
                     well as MAC layer packets.

   ifInBroadcastPkts Return the number of Broadcast packets received
                     on this interface. This includes data packets
                     as well as MAC layer packets.

   ifInDiscards      The total number of received packets which have
                     been discarded.
                     The possible reasons are: buffer shortage.

   ifInErrors        The number of inbound packets that contained
                     errors preventing them from being deliverable
                     to higher layers.
                     Possible reasons are: MAC FCS error.

   ifInUnknownProtos The number of frames with an unknown packet type.
                     This are MAC frames with an unknown packet type.

   ifOutOctets       Return zero.

   ifOutUcastPkts    Return zero.

   ifOutMulticastPkts
                     Return zero.

   ifOutBroadcastPkts
                     Return zero.



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RFC 2670                DOCSIS RF Interface MIB              August 1999


   ifOutDiscards     Return zero.

   ifOutErrors       Return zero.