rfc2662.txt

著名的RFC文档,其中有一些文档是已经翻译成中文的的.

Network Working Group                                        G. Bathrick
Request for Comments: 2662                      AG Communication Systems
Category: Standards Track                                          F. Ly
                                                Copper Mountain Networks
                                                             August 1999


           Definitions of Managed Objects for the ADSL Lines

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (1999).  All Rights Reserved.

Table of Contents

    1.  Abstract  ..............................................   1
    2.  The SNMP Network Management Framework  .................   2
    3.  Object Definitions .....................................   3
    4.  Relationship of the ADSL LINE MIB with standard MIBs ...   3
    5.  Conventions used in the MIB ............................   7
    6.  Conformance and Compliance .............................  17
    7.  Definitions ............................................  17
    8.  Acknowledgments ........................................ 110
    9.  References ............................................. 111
   10.  Security Considerations ................................ 113
   11.  Intellectual Property Notice ........................... 114
   12.  Authors' Addresses ..................................... 114
   13.  Full Copyright Statement ............................... 115

1.  Abstract

   This document defines a standard SNMP MIB for ADSL lines based on the
   ADSL Forum standard data model [9].  The ADSL standard describes
   ATU-C and ATU-R as two sides of the ADSL line.  This MIB covers both
   ATU-C and ATU-R agent's perspectives.  Each instance defined in the

   MIB represents a single ADSL line.






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   It should be noted that the ADSL Forum Network Management Working
   Group provided input towards the content of this document.  See the
   Acknowledgement Section for a list of individuals who made this
   document possible.

2.  The SNMP Network Management Framework

   The SNMP Management Framework presently consists of five major
   components:

   o  An overall architecture, described in RFC 2571 [13].

   o  Mechanisms for describing and naming objects and events for the
      purpose of management.  The first version of this Structure of
      Management Information (SMI) is called SMIv1 and described in STD
      16, RFC 1155 [14], STD 16, RFC 1212 [15] and RFC 1215 [16].  The
      second version, called SMIv2, is described in STD 58, RFC 2578
      [1], STD 58, RFC 2579 [2] and STD 58, RFC 2580 [17].

   o  Message protocols for transferring management information.  The
      first version of the SNMP message protocol is called SNMPv1 and
      described in STD 15, RFC 1157 [7].  A second version of the SNMP
      message protocol, which is not an Internet standards track
      protocol, is called SNMPv2c and described in RFC 1901 [18] and RFC
      1906 [19].  The third version of the message protocol is called
      SNMPv3 and described in RFC 1906 [19], RFC 2572 [20] and RFC 2574
      [21].

   o  Protocol operations for accessing management information.  The
      first set of protocol operations and associated PDU formats is
      described in STD 15, RFC 1157 [7].  A second set of protocol
      operations and associated PDU formats is described in RFC 1905
      [8].

   o  A set of fundamental applications described in RFC 2573 [22] and
      the view-based access control mechanism described in RFC 2575
      [23].

   This document specifies a MIB module that is compliant to the SMIv2.
   A MIB conforming to the SMIv1 can be produced through the appropriate
   translations.  The resulting translated MIB must be semantically
   equivalent, except where objects or events are omitted because no
   translation is possible (e.g., use of Counter64).  Some machine
   readable information in SMIv2 will be converted into textual
   descriptions in SMIv1 during the translation process.  However, this
   loss of machine readable information is not considered to change the
   semantics of the MIB.




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3.  Object Definitions

   Managed objects are accessed via a virtual information store, termed
   the Management Information Base or MIB.  Objects in the MIB are
   defined using the extended subset of Abstract Syntax Notation One
   (ASN.1) defined in the SMI.  In particular, each object type is named
   by an OBJECT IDENTIFIER, an administratively assigned name.  The
   object type together with an object instance serves to uniquely
   identify a specific instantiation of the object.  For human
   convenience, we often use a textual string, termed the descriptor, to
   also refer to the object type.

4.  Relationship of the ADSL LINE MIB with standard MIBs

   This section outlines the relationship of ADSL Line MIB with other
   MIBs described in RFCs and in their various degrees of
   "standardization".

4.1  Use of the IfTable

   The ADSL LINE MIB specifies the detailed attributes of a data
   interface.  As such, it needs to integrate with IF-MIB [5].  The IANA
   has assigned the following ifType(s) relative to ADSL:

       IANAifType ::= TEXTUAL-CONVENTION

           . . .

       SYNTAX INTEGER {

                . . .

           adsl(94),    -- Asymmetric Digital Subscriber Loop

                . . .

           adslInterleave(124),    -- ADSL Interleaved Channel
           adslFast(125),          -- ADSL Fast Channel

                . . .          }

   Interfaces of each of these types are modeled by this document.  Most
   MIB tables in this document represent information of one of these
   interface types and are indexed by ifIndex.  Remaining are `profile'
   tables which may be accessed by the profileIndex.  This is explained
   in more detail in section 5.4 Profiles.





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4.1.1  ADSL Interface Types

   As shown below, three ADSL interface types are defined in this
   document, namely physical, interleaved channel, and fast channel.
   The physical interface represents characteristics of the physical
   media associated with both the ATUC and ATUR.  The interleaved and
   fast channel interface represent the characteristics of the two types
   of ADSL channels.

   For each ADSL Line, a physical interface always exists.   Depending
   on which ADSL operational configuration is present (as listed in
   Figure 5), the channel interfaces (fast or interleaved) may or may
   not exist.

               ______                      ______
              |      |____________________|      |
              | ATUC |                    | ATUR |
              |      |____________________|      |
              |______|                    |______|

                 | <----- physical --------> |

                 | <--- fast channel ------> |

                 | <- interleaved channel -> |

                      Figure 1: ADSL Model

4.1.2  Use of IF-MIB  (Interface MIB RFC 2233) [5]

   The following attributes are part of the required
   ifGeneralInformationGroup object group specified in RFC 2233 [5], and
   are not duplicated in the ADSL MIB.  Keep in mind that these objects
   apply to the agent's view of the line.

















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              ifTable Object    Use for ADSL
   ==================================================================
              ifIndex           Interface index.

              ifDescr           See interfaces MIB [5]

              ifType            physical    - adsl(94)
                                fast        - adslFast(125)
                                interleaved - adslInterleave(124)

              ifSpeed           Transmit rate from the perspective
                                of the agent.

                                physical      - line rate
                                fast          - channel rate
                                interleaved   - channel rate

              ifPhysAddress     This object should have an octet string
                                with zero length.

              ifAdminStatus     See interfaces MIB [5]

              ifOperStatus      See interfaces MIB [5]

                                Supplemented by adslAturCurrStatus and
                                adslAturCurrStatus

              ifLastChange      See interfaces MIB [5]

              ifName            See interfaces MIB [5]

              ifLinkUpDownTrapEnable   See interfaces MIB [5]

                                Default set as follows:

                                physical      - enabled(1)
                                fast          - disabled(2)
                                interleaved   - disabled(2)

              ifHighSpeed       Speed of line in Mega-bits per second
                                (ifSpeed/1,000,000)

              ifConnectorPresent See interfaces MIB [5]

                                Default set as follows:

                                physical      - true(1)
                                fast          - false(2)



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                                interleaved   - false(2)

              ifAlias           See interfaces MIB [5]

              ifTableLastChange See interfaces MIB [5]

   ==================================================================

        Figure 2: Use of ifTable Objects: ifGeneralInformationGroup

   Use of the ifStackTable to associate the entries for physical, fast,
   interleaved channels, and higher layers (e.g., ATM) is shown below in
   figure 3.  Use of ifStackTable is necessary, because configuration
   information is stored in profile tables associated with the
   physical-layer ifEntry only.  The channels' ifEntrys need the
   ifStackTable to find their associated physical-layer entry and thus
   their configuration parameters.  (See Profile section, 5.4).

               ______       (ifEntry=j)        ______
              |      |      fast channel      |      |
              |      |________________________|      |
              |      |        and/or          |      |
              |      |                        |      |
              |      |     (ifEntry=k)        |      |
              |      |   interleaved channel  |      |
              |      |________________________|      |
              | ATUC |                        | ATUR |
              |      |                        |      |
              |      |     (ifEntry=i)        |      |
              |      |      physical          |      |
              |      |________________________|      |
              |______|                        |______|

               Figure 3: Use of ifStackTable (part 1)

   The ifStackTable is then used to show the relationships between the
   various ADSL interfaces, as illustrated below in figure 4.

                     HigherLayer   LowerLayer
                    --------------------------
                         j             i
                         k             i

                  Figure 4: Use of ifStackTable (part 2)

   The ifRcvAddressTable is not applicable for ADSL interfaces.





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4.2  Relationship with RFC 2037 [25]

   Implementation of the Entity MIB [25] is optional.  It in no way
   alters the information required in the adslLineMib, nor does it alter
   the relationship with IF-MIB.

   The Entity MIB introduces a standardized way of presenting the