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.

Network Working Group                                   M. St. Johns, Ed.
Request for Comments: 2670                                  @Home Network
Category: Proposed Standard                                   August 1999


       Radio Frequency (RF) Interface Management Information Base
                for MCNS/DOCSIS compliant RF interfaces


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.

Abstract

   This memo defines a portion of the Management Information Base (MIB)
   for use with network management protocols in the Internet community.
   In particular, it defines a basic set of managed objects for SNMP-
   based management of MCNS/DOCSIS compliant Radio Frequency (RF)
   interfaces.

   This memo specifies a MIB module in a manner that is compliant to the
   SNMP SMIv2 [5][6][7].  The set of objects are consistent with the
   SNMP framework and existing SNMP standards.

   This memo is a product of the IPCDN working group within the Internet
   Engineering Task Force.  Comments are solicited and should be
   addressed to the working group's mailing list at [e-mail]
   and/or the author.

 Table of Contents

   1 The SNMP Management Framework ................................... 3
   2 Glossary ........................................................ 4
   2.1 CATV .......................................................... 4
   2.2 Channel ....................................................... 4
   2.3 CM ............................................................ 4
   2.4 CMTS .......................................................... 4
   2.5 Codeword ...................................................... 4
   2.6 Data Packet ................................................... 4



St. Johns                       Standard                        [Page 1]

RFC 2670                DOCSIS RF Interface MIB              August 1999


   2.7 dBmV .......................................................... 4
   2.8 DOCSIS ........................................................ 5
   2.9 Downstream .................................................... 5
   2.10 Head-end ..................................................... 5
   2.11 MAC Packet ................................................... 5
   2.12 MCNS ......................................................... 5
   2.13 Mini-slot .................................................... 5
   2.14 QPSK ......................................................... 5
   2.15 QAM .......................................................... 5
   2.16 RF ........................................................... 5
   2.17 Symbol-times ................................................. 5
   2.18 Upstream ..................................................... 6
   3 Overview ........................................................ 6
   3.1 Structure of the MIB .......................................... 6
   3.1.1 docsIfBaseObjects ........................................... 6
   3.1.2 docsIfCmObjects ............................................. 7
   3.1.3 docsIfCmtsObjects ........................................... 7
   3.2 Relationship to the Interfaces MIB ............................ 7
   3.2.1 Layering Model .............................................. 7
   3.2.2 Virtual Circuits ............................................ 8
   3.2.3 ifTestTable ................................................. 9
   3.2.4 ifRcvAddressTable ........................................... 9
   3.2.5 ifEntry ..................................................... 9
   3.2.5.1 ifEntry for Downstream interfaces ......................... 9
   3.2.5.1.1 ifEntry for Downstream interfaces in Cable Modem
        Termination Systems .......................................... 9
   3.2.5.1.2 ifEntry for Downstream interfaces in Cable Modems ...... 11
   3.2.5.2 ifEntry for Upstream interfaces .......................... 12
   3.2.5.2.1  ifEntry for Upstream interfaces in Cable Modem
        Termination Systems ......................................... 12
   3.2.5.2.2 ifEntry for Upstream interfaces in Cable Modems ........ 14
   3.2.5.3 ifEntry for the MAC Layer ................................ 15
   4 Definitions .................................................... 18
   5 Acknowledgments ................................................ 69
   6 References ..................................................... 69
   7 Security Considerations ........................................ 70
   8 Intellectual Property .......................................... 71
   9 Author's Address ............................................... 71
   10 Full Copyright Statement ...................................... 72












St. Johns                       Standard                        [Page 2]

RFC 2670                DOCSIS RF Interface MIB              August 1999


1.  The SNMP Management Framework

   The SNMP Management Framework presently consists of five major
   components:

   o   An overall architecture, described in RFC 2571 [1].

   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 [2], STD 16, RFC 1212 [3] and RFC 1215 [4]. The
       second version, called SMIv2, is described in STD 58, RFC 2578
       [5], STD 58, RFC 2579 [6] and STD 58, RFC 2580 [7].

   o   Message protocols for transferring management information. The
       first version of the SNMP message protocol is called SNMPv1 and
       described in RFC 1157 [8]. A second version of the SNMP message
       protocol, which is not an Internet standards track protocol, is
       called SNMPv2c and described in RFC 1901 [9] and RFC 1906 [10].
       The third version of the message protocol is called SNMPv3 and
       described in RFC 1906 [10], RFC 2572 [11] and RFC 2574 [12].

   o   Protocol operations for accessing management information. The
       first set of protocol operations and associated PDU formats is
       described in STD 15, RFC 1157 [8]. A second set of protocol
       operations and associated PDU formats is described in RFC 1905
       [13].

   o   A set of fundamental applications described in RFC 2573 [14] and
       the view-based access control mechanism described in RFC 2575
       [15].

   Managed objects are accessed via a virtual information store, termed
   the Management Information Base or MIB.  Objects in the MIB are
   defined using the mechanisms defined in the SMI.

   This memo 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 (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.






St. Johns                       Standard                        [Page 3]

RFC 2670                DOCSIS RF Interface MIB              August 1999


2.  Glossary

   The terms in this document are derived either from normal cable
   system usage, or from the documents associated with the Data Over
   Cable Service Interface Specification process.

2.1.  CATV

   Originally "Community Antenna Television", now used to refer to any
   cable or hybrid fiber and cable system used to deliver video signals
   to a community.

2.2.  Channel

   A specific frequency allocation with an RF medium, specified by
   channel width in Hertz (cycles per second) and by center frequency.
   Within the US Cable Systems, upstream channels are generally
   allocated from the 5-42MHz range while down stream channels are
   generally allocated from the 50-750MHz range depending on the
   capabilities of the given system.  The typical broadcast channel
   width in the US is 6MHz.  Upstream channel widths for DOCSIS vary.

2.3.  CM   Cable Modem.

   A CM acts as a "slave" station in a DOCSIS compliant cable data
   system.

2.4.  CMTS   Cable Modem Termination System.

   A generic term covering a cable bridge or cable router in a head-end.
   A CMTS acts as the master station in a DOCSIS compliant cable data
   system.  It is the only station that transmits downstream, and it
   controls the scheduling of upstream transmissions by its associated
   CMs.

2.5.  Codeword

   See [16]. A characteristic of the Foward Error Correction scheme used
   above the RF media layer.

2.6.  Data Packet

   The payload portion of the MAC Packet.

2.7.  dBmV

   Decibel relative to one milli-volt. A measure of RF power.




St. Johns                       Standard                        [Page 4]

RFC 2670                DOCSIS RF Interface MIB              August 1999


2.8.  DOCSIS

   "Data Over Cable Interface Specification".  A term referring to the
   ITU-T J.112 Annex B standard for cable modem systems [20].

2.9.  Downstream

   The direction from the head-end towards the subscriber.

2.10.  Head-end

   The origination point in most cable systems of the subscriber video
   signals.

2.11.  MAC Packet

   A DOCSIS PDU.

2.12.  MCNS

   "Multimedia Cable Network System".  Generally replaced in usage by
   DOCSIS.

2.13.  Mini-slot

   See [16].  In general, an interval of time which is allocated by the
   CMTS to a given CM for that CM to transmit in an upstream direction.

2.14.  QPSK   Quadrature Phase Shift Keying.

   A particular modulation scheme on an RF medium. See [19].

2.15.  QAM   Quadrature Amplitude Modulation.

   A particular modulation scheme on on RF medium.  Usually expressed
   with a number indicating the size of the modulation constellation
   (e.g. 16 QAM). See [19], or any other book on digital communications
   over RF for a complete explanation of this.

2.16.  RF

   Radio Frequency.

2.17.  Symbol-times

   See [16]. A characteristic of the RF modulation scheme.





St. Johns                       Standard                        [Page 5]

RFC 2670                DOCSIS RF Interface MIB              August 1999


2.18.  Upstream

   The direction from the subscriber towards the head-end.

3.  Overview

   This MIB provides a set of objects required for the management of
   MCNS/DOCSIS compliant Cable Modem (CM) and Cable Modem Termination
   System (CMTS) RF interfaces.  The specification is derived in part
   from the parameters and protocols described in DOCSIS Radio Frequency
   Interface Specification [16].

3.1.  Structure of the MIB

   This MIB is structured as three groups:

   o    Management information pertinent to both Cable Modems (CM) and
        Cable Modem Termination Systems (CMTS) (docsIfBaseObjects).

   o    Management information pertinent to Cable Modems only
        (docsIfCmObjects).

   o    Management information pertinent to Cable Modem Termination
        Systems only (docsIfCmtsObjects).

   Tables within each of these groups group objects functionally - e.g.
   Quality of Service, Channel characteristics, MAC layer management,
   etc.  Rows created automatically (e.g. by the device according to the
   hardware configuration) may and generally will have a mixture of
   configuration and status objects within them.  Rows that are meant to
   be created by the management station are generally restricted to
   configuration (read-create) objects.

3.1.1.  docsIfBaseObjects

   docsIfDownstreamChannelTable - This table describes the active
   downstream channels for a CMTS and the received downstream channel
   for a CM.

   docsIfUpstreamChannelTable - This table describes the active upstream
   channels for a a CMTS and the current upstream transmission channel
   for a CM.

   docsIfQosProfileTable - This table describes the valid Quality of
   Service service profiles for the cable data system.

   docsIfSignalQualityTable - This table is used to monitor RF signal
   quality characteristics of received signals.



St. Johns                       Standard                        [Page 6]

RFC 2670                DOCSIS RF Interface MIB              August 1999


3.1.2.  docsIfCmObjects

   docsIfCmMacTable - This table is used to monitor the DOCSIS MAC
   interface and can be considered an extension to the ifEntry.

   docsIfCmServiceTable - This table describes the upstream service
   queues available at this CM.  There is a comparable table at the
   CMTS, docsIfCmtsServiceEntry, which describes the service queues from
   the point of view of the CMTS.

3.1.3.  docsIfCmtsObjects

   docsIfCmtsStatusTable - This table provides a set of aggregated
   counters which roll-up values and events that occur on the underlying
   sub-interfaces.

   docsIfCmtsCmStatusTable - This table is used to hold information
   about known (e.g. registered) cable modems on the system serviced by
   this CMTS.

   docsIfCmtsServiceEntry - This table provides access to the
   information related to upstream service queues.

   docsIfCmtsModulationTable - This table allows control over the
   modulation profiles for RF channels associated with this CMTS.

   docsIfCmtsMacToCmTable - This table allows fast access into the