rfc1407.txt

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Network Working Group                                             T. Cox
Request for Comments: 1407                                     K. Tesink
Obsoletes: 1233                             Bell Communications Research
                                                                 Editors
                                                            January 1993


                     Definitions of Managed Objects
                     for the DS3/E3 Interface Type

Status of this Memo

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

Abstract

   This memo defines an extension to the Management Information Base
   (MIB) for use with network management protocols in TCP/IP-based
   internets.  In particular, it defines objects for managing DS3 and E3
   Interfaces.  This document is a companion document with Definitions
   of Managed Objects for the DS1 Interface Type.

   This document entirely replaces RFC 1233, which contains a
   fundamental error: many objects are encoded as Counters that must be
   encoded as INTEGERs or Gauges.  The magnitude of the change required
   is sufficient that virtually every object changed.  Therefore, the
   MIB documented in RFC 1233 should not be implemented.

Table of Contents

   1. The Network Management Framework ......................    2
   2. Objects ...............................................    2
   2.1 Format of Definitions ................................    3
   2.2 Changes from RFC 1233 ................................    3
   3. Overview ..............................................    5
   3.1 Binding between ifIndex and DS3/E3 Interfaces ........    5
   3.2 Objectives of this MIB Module ........................    7
   3.3 DS3/E3 Terminology ...................................    7
   3.3.1 Error Events .......................................    7
   3.3.2 Performance Parameters .............................    8
   3.3.3 Performance Defects ................................   10
   3.3.4 Other Terms ........................................   11
   4. Object Definitions ....................................   12
   4.1 The DS3/E3 Near End Group ............................   12



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RFC 1407                       DS3/E3 MIB                   January 1993


   4.1.1 The DS3/E3 Configuration ...........................   12
   4.1.2 The DS3/E3 Current .................................   18
   4.1.3 The DS3/E3 Interval ................................   21
   4.1.4 The DS3/E3 Total ...................................   25
   4.2 The DS3 Far End Group ................................   29
   4.2.1 The DS3 Far End Configuration ......................   29
   4.2.2 The DS3 Far End Current ............................   31
   4.2.3 The DS3 Far End Interval ...........................   34
   4.2.4 The DS3 Far End Total ..............................   36
   4.3 The DS3/E3 Fractional Group ..........................   38
   5. Acknowledgments .......................................   41
   6. References ............................................   41
   7. Security Considerations ...............................   43
   8. Authors' Addresses ....................................   43

1.  The Network Management Framework

   The Internet-standard Network Management Framework consists of three
   components.  They are:

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

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

      STD 15/RFC 1157 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.

2.  Objects

   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.  In particular, each object has a name, a syntax,
   and an encoding.  The name is an object identifier, an
   administratively assigned name, which specifies an object type.  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 OBJECT
   DESCRIPTOR, to also refer to the object type.



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RFC 1407                       DS3/E3 MIB                   January 1993


   The syntax of an object type defines the abstract data structure
   corresponding to that object type.  The ASN.1 language is used for
   this purpose.  However, the SMI [3] purposely restricts the ASN.1
   constructs which may be used.  These restrictions are explicitly made
   for simplicity.

   The encoding of an object type is simply how that object type is
   represented using the object type's syntax.  Implicitly tied to the
   notion of an object type's syntax and encoding is how the object type
   is represented when being transmitted on the network.  The SMI
   specifies the use of the basic encoding rules of ASN.1 [8], subject
   to the additional requirements imposed by the SNMP.

2.1.  Format of Definitions

   Section 4 contains contains the specification of all object types
   contained in this MIB module.  The object types are defined using the
   conventions defined in the SMI, as amended by the extensions
   specified in STD 16, RFC 1212 [13].

2.2.  Changes from RFC 1233

   This MIB obsoletes RFC 1233.  The changes from RFC 1233 are the
   following:

      --  This MIB module contains information to manage
          an E3 interface, also.

      --  This MIB module contains three groups:
           DS3/E3 Near End Group which is mandatory,
           DS3 Far End Group which is optional, and
           DS3 Fractional Group which is optional.

      --  The DS3 Far End Group is a new group and contains
          configuration information and statistics
          that are collected from the far end DS3/E3 interface.
          Presently, the Far End Group may only be implemented by
          DS3 systems that use C-bit Parity or SYNTRAN.

      --  The DS3 Fractional Group is a new group and is
          modeled after the DS1 Fractional Group.

      --  ds3CSUIndex has been redefined and renamed
          to dsx3LineIndex.  This object
          is the identifier of a DS3/E3 Interface on a device.
          On a CSU, a single DS3/E3 data stream will cross two DS3/E3
          interfaces, which have separate dsx3LineIndex values.




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RFC 1407                       DS3/E3 MIB                   January 1993


      --  ds3Index has been redefined and renamed to
          dsx3IfIndex.  This value for this
          object is equal to the value of ifIndex from the Interfaces
          table of MIB II (STD 17, RFC 1213).

      --  The ACCESS for objects in the dsx3ConfigTable has
          been set to read-write for items that are configurable.

      --  The dsx3ZeroCoding has been renamed to dsx3LineCoding.

      --  A new object has been added called dsx3LoopbackConfig,
          which better describes the loopback capabilities of
          a DS3/E3 interface on a device.

      --  The dsx3SendCode object has been updated to reflect
          different types of loopback messages.

      --  A new object has been added called dsx3LineStatus.
          This object better describes the status (e.g.,
          failure state and loopback state) of a
          DS3/E3 interface.

      --  A new object has been added called dsx3TransmitClockSource.
          This object identifies the source for the transmit clock.

      --  All Counters have been changed to Gauges.

      --  A Line Errored Seconds object has been added to
          all near end tables.

      --  Line Coding Violations are counted instead of Bipolar
          Violations.

      --  A new Coding Violation counter has been added to count
          coding violations reported via the C-bits of SYNTRAN
          and C-bit Parity DS3 applications.
          The original Coding Violation counter has been renamed
          to PCV to mean coding violations reported via the P-bits.
          This count is also added for symmetry with the far end
          statistics.

      --  A new Errored Second counter and Severely Errored Second
          counter has been added to count these performance events
          via the C-bits of the SYNTRAN and C-bit Parity DS3
          applications.  The original ES and SES counters have been
          renamed to PES and PSES to mean reported via the P-bits.
          These counts are also added for symmetry with the far end
          statistics.



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RFC 1407                       DS3/E3 MIB                   January 1993


3.  Overview

   These objects are used when the particular media being used to
   realize an interface is a DS3/E3 interface.  At present, this applies
   to these values of the ifType variable in the Internet-standard MIB:

               ds3 (30)

   The DS3 definitions contained herein are based on the DS3
   specifications in ANSI T1.102-1987, ANSI T1.107-1988, ANSI T1.107a-
   1990, and ANSI T1.404-1989 [9,10,10a,11].  The E3 definitions
   contained herein are based on the E3 specifications in CCITT G.751
   [14].

3.1.  Binding between ifIndex and DS3/E3 Interfaces

   Different physical configurations for the support of SNMP with DS3/E3
   equipment exist. To accommodate these scenarios, two different
   indices for DS3/E3 interfaces are introduced in this MIB.  These
   indices are dsx3IfIndex and dsx3LineIndex.

   External interface scenario: the SNMP Agent represents all managed
   DS3/E3 lines as external interfaces (for example, an Agent residing
   on the device supporting DS3/E3 interfaces directly):

   For this scenario, all interfaces are assigned an integer value equal
   to ifIndex, and the following applies:

             ifIndex=dsx3IfIndex=dsx3LineIndex for all interfaces.

   The dsx3IfIndex column of the DS3/E3 Configuration table relates each
   DS3/E3 interface to its corresponding interface (ifIndex) in the
   Internet-standard MIB (MIB-II STD 17, RFC 1213).

   External&Internal interface scenario: the SNMP Agents resides on an
   host external from the device supporting DS3/E3 interfaces (e.g., a
   router). The Agent represents both the host and the DS3/E3 device.
   The index dsx3LineIndex is used to not only represent the DS3/E3
   interfaces external from the host/DS3/E3-device combination, but also
   the DS3/E3 interfaces connecting the host and the DS3/E3 device.  The
   index dsx3IfIndex is always equal to ifIndex.

   Example:

   A shelf full of CSUs connected to a Router. An SNMP Agent residing on
   the router proxies for itself and the CSU. The router has also an
   Ethernet interface:




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RFC 1407                       DS3/E3 MIB                   January 1993


          +-----+
    |     |     |
    |     |     |               +---------------------+
    |E    |     |  44.736 MBPS  |   ds3 M13    Line#A | ds3 C-bit Parity
    |t    |  R  |---------------+ - - - - -  - - -  - +------>
    |h    |     |               |                     |
    |e    |  O  |  44.736 MBPS  |   ds3 M13    Line#B | ds3 C-bit Parity
    |r    |     |---------------+ - - - - - - - - - - +------>
    |n    |  U  |               |                     |
    |e    |     |  44.736 MBPS  |   ds3 M13    Line#C | ds3 C-bit Parity
    |t    |  T  |---------------+ - - - -- -- - - - - +------>
    |     |     |               |                     |
    |-----|  E  |  44.736 MBPS  |   ds3 M13    Line#D | ds3 C-bit Parity
    |     |     |---------------+ -  - - - -- - - - - +------>
    |     |  R  |               |_____________________|
    |     |     |
    |     +-----+

   The assignment of the index values could for example be:

            ifIndex (= dsx3IfIndex)                     dsx3LineIndex

                    1                   NA                  NA (Ethernet)
                    2      Line#A   Router Side             6
                    2      Line#A   Network Side            7
                    3      Line#B   Router Side             8
                    3      Line#B   Network Side            9
                    4      Line#C   Router Side            10
                    4      Line#C   Network Side           11
                    5      Line#D   Router Side            12
                    5      Line#D   Network Side           13

   For this example, ifNumber is equal to 5.  Note the following
   description of dsx3LineIndex: the dsx3LineIndex identifies a DS3/E3
   Interface on a managed device.  If there is an ifEntry that is
   directly associated with this and only this DS3/E3 interface, it
   should have the same value as ifIndex.  Otherwise, number the
   dsx3LineIndices with an unique identifier following the rules of
   choosing a number greater than ifNumber and numbering inside
   interfaces (e.g., equipment side) with even numbers and outside
   interfaces (e.g., network side) with odd numbers.

   If the CSU shelf is managed by itself by a local SNMP Agent, the
   situation would be:







Trunk MIB Working Group                                         [Page 6]