rfc1623.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                                      F. Kastenholz
Request for Comments: 1623                            FTP Software, Inc.
Obsoletes: 1398                                                 May 1994
STD: 50
Category: Standards Track


                   Definitions of Managed Objects for
                   the Ethernet-like Interface Types

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.

Table of Contents

   Introduction .............................................    1
   1. The SNMP Network Management Framework .................    2
   1.1 Object Definitions ...................................    2
   2. Change Log ............................................    2
   3. Overview ..............................................    3
   3.1 Relation to RFC 1213 .................................    4
   3.2 Relation to RFC 1573 .................................    4
   3.2.1 Layering Model .....................................    4
   3.2.2 Virtual Circuits ...................................    4
   3.2.3 ifTestTable ........................................    4
   3.2.4 ifRcvAddressTable ..................................    5
   3.2.5 ifPhysAddress ......................................    5
   3.2.6 ifType .............................................    6
   4. Definitions ...........................................    6
   5. Acknowledgements ......................................   16
   6. References ............................................   17
   7. Security Considerations ...............................   19
   8. Author's Address ......................................   19

Introduction

   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 objects for managing ethernet-like objects.

   This memo also includes a MIB module.  This MIB module corrects minor
   errors in the earlier version of this MIB: RFC 1398 [15].




Kastenholz                                                      [Page 1]

RFC 1623                   Ethernet-Like MIB                    May 1994


1.  The SNMP Network Management Framework

   The SNMP Network Management Framework consists of three major
   components.  They are:

      o    STD 16/RFC 1155 [3] which defines the SMI, the mechanisms
           used for describing and naming objects for the purpose of
           management.  STD 16/RFC 1212 [13] defines a more concise
           description mechanism, which is wholly consistent with
           the SMI.

      o    RFC 1156 [4] which defines MIB-I, the core set of managed
           objects for the Internet suite of protocols.  STD 17/RFC
           1213 [6] defines MIB-II, an evolution of MIB-I based on
           implementation experience and new operational
           requirements.

      o    STD 15/RFC 1157 [5] which defines the SNMP, the protocol
           used for network access to managed objects.

   The Framework permits new objects to be defined for the purpose of
   experimentation and evaluation.

1.1.  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 subset of Abstract Syntax Notation One (ASN.1) [7]
   defined in the SMI [16].  In particular, each object 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
   refer to the object type.

2.  Change Log

   This section enumerates changes made to RFC 1398 to produce this
   document.

    (1)   A section describing the applicability of various parts
          of RFC 1573 to ethernet-like interfaces has been added.

    (2)   A minor error in the description of the TDR test was
          fixed.

    (3)   A loopback test was defined to replace the standard
          loopback test that was defined in RFC 1229.



Kastenholz                                                      [Page 2]

RFC 1623                   Ethernet-Like MIB                    May 1994


    (4)   The description of dot3CollFrequencies was made a bit
          clearer.

    (5)   A new object, EtherChipset, has been added. This object
          replaces the ifExtnsChipSet object, which has been
          removed per the Interface MIB Evolution effort.

    (6)   Several minor editorial changes, spelling corrections,
          grammar and punctuation corrections, and so forth, were
          made.

3.  Overview

   Instances of these object types represent attributes of an interface
   to an ethernet-like communications medium.  At present, ethernet-like
   media are identified by three values of the ifType object in the
   Internet-standard MIB:

         ethernet-csmacd(6)
         iso88023-csmacd(7)
         starLan(11)

   For these interfaces, the value of the ifSpecific variable in the
   MIB-II [6] has the OBJECT IDENTIFIER value:

      dot3    OBJECT IDENTIFER ::= { experimental 3 }

   The definitions presented here are based on the IEEE 802.3 Layer
   Management Specification [9], as originally interpreted by Frank
   Kastenholz then of Interlan in [10].  Implementors of these MIB
   objects should note that the IEEE document explicitly describes (in
   the form of Pascal pseudocode) when, where, and how various MAC
   attributes are measured.  The IEEE document also describes the
   effects of MAC actions that may be invoked by manipulating instances
   of the MIB objects defined here.

   To the extent that some of the attributes defined in [9] are
   represented by previously defined objects in the Internet-standard
   MIB or in the Generic Interface Extensions MIB [11], such attributes
   are not redundantly represented by objects defined in this memo.
   Among the attributes represented by objects defined in other memos
   are the number of octets transmitted or received on a particular
   interface, the number of frames transmitted or received on a
   particular interface, the promiscuous status of an interface, the MAC
   address of an interface, and multicast information associated with an
   interface.





Kastenholz                                                      [Page 3]

RFC 1623                   Ethernet-Like MIB                    May 1994


3.1.  Relation to RFC 1213

   This section applies only when this MIB is used in conjunction with
   the "old" (i.e., pre-RFC 1573) interface group.

   The relationship between an ethernet-like interface and an interface
   in the context of the Internet-standard MIB is one-to-one.  As such,
   the value of an ifIndex object instance can be directly used to
   identify corresponding instances of the objects defined herein.

3.2.  Relation to RFC 1573

   RFC 1573, the Interface MIB Evolution, requires that any MIB which is
   an adjunct of the Interface MIB, clarify specific areas within the
   Interface MIB.  These areas were intentionally left vague in RFC 1573
   to avoid over constraining the MIB, thereby precluding management of
   certain media-types.

   Section 3.3 of RFC 1573 enumerates several areas which a media-
   specific MIB must clarify.  Each of these areas is addressed in a
   following subsection.  The implementor is referred to RFC 1573 in
   order to understand the general intent of these areas.

3.2.1.  Layering Model

   This MIB does not provide for layering.  There are no sublayers.

   EDITOR'S NOTE:

      I could forsee the development of an 802.2 and enet-transceiver
      MIB.  They could be higher and lower sublayers, respectively.  All
      that THIS document should do is allude to the possibilities and
      urge the implementor to be aware of the possibility and that they
      may have requirements which supersede the requirements in this
      document.

3.2.2.  Virtual Circuits

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

3.2.3.  ifTestTable

   This MIB defines two tests for media which are instumented with this
   MIB; TDR and Loopback.  Implementation of these tests is not
   required.  Many common interface chips do not support one or both of
   these tests.




Kastenholz                                                      [Page 4]

RFC 1623                   Ethernet-Like MIB                    May 1994


   These two tests are provided as a convenience, allowing a common
   method to invoke the test.

   Standard MIBs do not include objects in which to return the results
   of the TDR test.  Any needed objects MUST be provided in the vendor
   specific MIB.

3.2.4.  ifRcvAddressTable

   This table contains all IEEE 802.3 addresses, unicast, multicast, and
   broadcast, for which this interface will receive packets and forward
   them up to a higher layer entity for local consumption.  The format
   of the address, contained in ifRcvAddressAddress, is the same as for
   ifPhysAddress.

   In the event that the interface is part of a MAC bridge, this table
   does not include unicast addresses which are accepted for possible
   forwarding out some other port.  This table is explicitly not
   intended to provide a bridge address filtering mechanism.

3.2.5.  ifPhysAddress

   This object contains the IEEE 802.3 address which is placed in the
   source-address field of any Ethernet, Starlan, or IEEE 802.3 frames
   that originate at this interface.  Usually this will be kept in ROM
   on the interface hardware.  Some systems may set this address via
   software.

   In a system where there are several such addresses the designer has a
   tougher choice.  The address chosen should be the one most likely to
   be of use to network management (e.g.  the address placed in ARP
   responses for systems which are primarily IP systems).

   If the designer truly can not chose, use of the factory- provided ROM
   address is suggested.

   If the address can not be determined, an octet string of zero length
   should be returned.

   The address is stored in binary in this object.  The address is
   stored in "canonical" bit order, that is, the Group Bit is positioned
   as the low-order bit of the first octet.  Thus, the first byte of a
   multicast address would have the bit 0x01 set.








Kastenholz                                                      [Page 5]

RFC 1623                   Ethernet-Like MIB                    May 1994


3.2.6.  ifType

   This MIB applies to interfaces which have any of the following three
   ifType values:

         ethernet-csmacd(6)
         iso88023-csmacd(7)
         starLan(11)

   Interfaces with any of these ifType values map to the EtherLike-MIB
   in the same manner.  The EtherLike-MIB applies equally to all three
   types; there are no implementation differences.

4.  Definitions

   EtherLike-MIB DEFINITIONS ::= BEGIN

      IMPORTS
          Counter, Gauge  FROM RFC1155-SMI
          transmission    FROM RFC1213-MIB
          OBJECT-TYPE     FROM RFC-1212;

       -- This MIB module uses the extended OBJECT-TYPE macro as
       -- defined in RFC-1212.

      dot3    OBJECT IDENTIFIER ::= { transmission 7 }

      -- the Ethernet-like Statistics group

       dot3StatsTable  OBJECT-TYPE
            SYNTAX     SEQUENCE OF Dot3StatsEntry
            ACCESS     not-accessible
            STATUS     mandatory
            DESCRIPTION
             "Statistics for a collection of ethernet-like
             interfaces attached to a particular system."
            ::= { dot3 2 }


       dot3StatsEntry   OBJECT-TYPE
            SYNTAX      Dot3StatsEntry
            ACCESS      not-accessible
            STATUS      mandatory
            DESCRIPTION
              "Statistics for a particular interface to an
              ethernet-like medium."
            INDEX     { dot3StatsIndex }
            ::= { dot3StatsTable 1 }



Kastenholz                                                      [Page 6]

RFC 1623                   Ethernet-Like MIB                    May 1994


       Dot3StatsEntry ::= SEQUENCE {
            dot3StatsIndex                      INTEGER,
            dot3StatsAlignmentErrors            Counter,
            dot3StatsFCSErrors                  Counter,
            dot3StatsSingleCollisionFrames      Counter,
            dot3StatsMultipleCollisionFrames    Counter,
            dot3StatsSQETestErrors              Counter,
            dot3StatsDeferredTransmissions      Counter,
            dot3StatsLateCollisions             Counter,
            dot3StatsExcessiveCollisions        Counter,
            dot3StatsInternalMacTransmitErrors  Counter,
            dot3StatsCarrierSenseErrors         Counter,
            dot3StatsFrameTooLongs              Counter,
            dot3StatsInternalMacReceiveErrors   Counter