path: root/doc/rfc/rfc2495.txt

Network Working Group                              D. Fowler, Editor
Request for Comments: 2495                        Newbridge Networks
Obsoletes: 1406                                         January 1999
Category: Standards Track


                     Definitions of Managed Objects
              for the DS1, E1, DS2 and E2 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.

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 describes objects used for managing DS1, E1, DS2
   and E2 interfaces.  This document is a companion document with
   Definitions of Managed Objects for the DS0 (RFC 2494 [30]), DS3/E3
   (RFC 2496 [28]), and the work in progress, SONET/SDH Interface Types.

   This memo specifies a MIB module in a manner that is both compliant
   to the SNMPv2 SMI, and semantically identical to the peer SNMPv1
   definitions.

Table of Contents

   1 The SNMP Management Framework ................................    2
   1.1 Changes from RFC1406 .......................................    3
   2 Overview .....................................................    4
   2.1 Use of ifTable for DS1 Layer ...............................    5
   2.2 Usage Guidelines ...........................................    6
   2.2.1 Usage of ifStackTable for Routers and DSUs ...............    6
   2.2.2 Usage of ifStackTable for DS1/E1 on DS2/E2 ...............    8
   2.2.3 Usage of Channelization for DS3, DS1, DS0 ................    9
   2.2.4 Usage of Channelization for DS3, DS2, DS1 ................    9
   2.2.5 Usage of Loopbacks .......................................   10
   2.3 Objectives of this MIB Module ..............................   11
   2.4 DS1 Terminology ............................................   11



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   2.4.1 Error Events .............................................   12
   2.4.2 Performance Defects ......................................   12
   2.4.3 Performance Parameters ...................................   14
   2.4.4 Failure States ...........................................   17
   2.4.5 Other Terms ..............................................   21
   3 Object Definitions ...........................................   21
   3.1 The DS1 Near End Group .....................................   22
   3.1.1 The DS1 Configuration Table ..............................   22
   3.1.2 The DS1 Current Table ....................................   33
   3.1.3 The DS1 Interval Table ...................................   36
   3.1.4 The DS1 Total Table ......................................   39
   3.1.5 The DS1 Channel Table ....................................   42
   3.2 The DS1 Far End Group ......................................   43
   3.2.1 The DS1 Far End Current Table ............................   43
   3.2.2 The DS1 Far End Interval Table ...........................   47
   3.2.3 The DS1 Far End Total Table ..............................   50
   3.3 The DS1 Fractional Table ...................................   53
   3.4 The DS1 Trap Group .........................................   55
   3.5 Conformance Groups .........................................   61
   4 Appendix A - Use of dsx1IfIndex and dsx1LineIndex ............   66
   5 Appendix B - The delay approach to Unavialable Seconds.  .....   69
   6 Intellectual Property ........................................   70
   7 Acknowledgments ..............................................   70
   8 References ...................................................   71
   9 Security Considerations ......................................   73
   10 Author's Address ............................................   74
   11 Full Copyright Statement ....................................   75

1.  The SNMP Management Framework

   The SNMP Management Framework presently consists of five major
   components:

    o   An overall architecture, described in RFC 2271 [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 RFC 1902 [5], RFC
        1903 [6] and RFC 1904 [7].

    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 [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



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        called SNMPv3 and described in RFC 1906 [10], RFC 2272 [11] and
        RFC 2274 [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 2273 [14] and
        the view-based access control mechanism described in RFC 2275
        [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.

1.1.  Changes from RFC1406

   The changes from RFC1406 are the following:

        (1)  The Fractional Table has been deprecated.

        (2)  This document uses SMIv2.

        (3)  Usage is given for ifTable and ifXTable.

        (4)  Example usage of ifStackTable is included.

        (5)  dsx1IfIndex has been deprecated.

        (6)  Support for DS2 and E2 have been added.

        (7)  Additional lineTypes for DS2, E2, and unframed E1
             were added.

        (8)  The definition of valid intervals has been clarified
             for the case where the agent proxied for other devices.  In
             particular, the treatment of missing intervals has been
             clarified.




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        (9)  An inward loopback has been added.

        (10) Additional lineStatus bits have been added for Near End in
             Unavailable Signal State, Carrier Equipment Out of Service,
             DS2 Payload AIS, and DS2 Performance Threshold.

        (11) A read-write line Length object has been added.

        (12) Signal mode of other has been added.

        (13) Added a lineStatus last change, trap and enabler.

        (14) The e1(19) ifType has been obsoleted so this MIB
             does not list it as a supported ifType.

        (15) Textual Conventions for statistics objects have been used.

        (16) A new object, dsx1LoopbackStatus has been introduced to
             reflect the loopbacks established on a DS1 interface and
             the source to the requests.  dsx1LoopbackConfig continues
             to be the desired loopback state while dsx1LoopbackStatus
             reflects the actual state.

        (17) A dual loopback has been added to allow the setting of an
             inward loopback and a line loopback at the same time.

        (18) An object indicating which channel to use within a parent
             object (i.e. DS3) has been added.

        (19) An object has been added to indicate whether or not this
             DS1/E1 is channelized.

        (20) Line coding type of B6ZS has been added for DS2

2.  Overview

   These objects are used when the particular media being used to
   realize an interface is a DS1/E1/DS2/E2 interface.  At present, this
   applies to these values of the ifType variable in the Internet-
   standard MIB:

        ds1 (18)

   The definitions contained herein are based on the AT&T T-1 Superframe
   (a.k.a., D4) and Extended Superframe (ESF) formats [17, 18], the
   latter of which conforms to ANSI specifications [19], and the CCITT
   Recommendations [20, 21], referred to as E1 for the rest of this
   memo.



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   The various DS1 and E1 line disciplines are similar enough that
   separate MIBs are unwarranted, although there are some differences.
   For example, Loss of Frame is defined more rigorously in the ESF
   specification than in the D4 specification, but it is defined in
   both.  Therefore,  interface types e1(19) and g703at2mb(67) have been
   obsoleted.

   Where it is necessary to distinguish between the flavors of E1 with
   and without CRC, E1-CRC denotes the "with CRC" form (G.704 Table 4b)
   and E1-noCRC denotes the "without CRC" form (G.704 Table 4a).

2.1.  Use of ifTable for DS1 Layer

   Only the ifGeneralGroup needs to be supported.

           ifTable Object    Use for DS1 Layer
======================================================================
           ifIndex           Interface index.

           ifDescr           See interfaces MIB [16]

           ifType            ds1(18)

           ifSpeed           Speed of line rate
                             DS1 - 1544000
                             E1  - 2048000
                             DS2 - 6312000
                             E2  - 8448000

           ifPhysAddress     The value of the Circuit Identifier.
                             If no Circuit Identifier has been assigned
                             this object should have an octet string
                             with zero length.

           ifAdminStatus     See interfaces MIB [16]

           ifOperStatus      See interfaces MIB [16]

           ifLastChange      See interfaces MIB [16]

           ifName            See interfaces MIB [16].

           ifLinkUpDownTrapEnable   Set to enabled(1).

           ifHighSpeed       Speed of line in Mega-bits per second
                             (2, 6, or 8)

           ifConnectorPresent Set to true(1) normally, except for



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                              cases such as DS1/E1 over AAL1/ATM where
                              false(2) is appropriate

2.2.  Usage Guidelines

2.2.1.  Usage of ifStackTable for Routers and DSUs

   The object dsx1IfIndex has been deprecated.  This object previously
   allowed a very special proxy situation to exist for Routers and CSUs.
   This section now describes how to use ifStackTable to represent this
   relationship.

   The paragraphs discussing dsx1IfIndex and dsx1LineIndex have been
   preserved in Appendix A for informational purposes.

   The ifStackTable is used in the proxy case to represent the
   association between pairs of interfaces, e.g. this T1 is attached to
   that T1.  This use is consistent with the use of the ifStackTable to
   show the association between various sub-layers of an interface.  In
   both cases entire PDUs are exchanged between the interface pairs - in
   the case of a T1, entire T1 frames are exchanged; in the case of PPP
   and HDLC, entire HDLC frames are exchanged.  This usage is not meant
   to suggest the use of the ifStackTable to represent Time Division
   Multiplexing (TDM) connections in general.

   External&Internal interface scenario: the SNMP Agent resides on a
   host external from the device supporting DS1 interfaces (e.g., a
   router). The Agent represents both the host and the DS1 device.

   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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         +-----+
   |     |     |
   |     |     |               +---------------------+
   |E    |     |  1.544  MBPS  |              Line#A | DS1 Link
   |t    |  R  |---------------+ - - - - -  - - -  - +------>
   |h    |     |               |                     |
   |e    |  O  |  1.544  MBPS  |              Line#B | DS1 Link
   |r    |     |---------------+ - - - - - - - - - - +------>
   |n    |  U  |               |  CSU Shelf          |
   |e    |     |  1.544  MBPS  |              Line#C | DS1 Link
   |t    |  T  |---------------+ - - - -- -- - - - - +------>
   |     |     |               |                     |
   |-----|  E  |  1.544  MBPS  |              Line#D | DS1 Link
   |     |     |---------------+ -  - - - -- - - - - +------>
   |     |  R  |               |_____________________|
   |     |     |
   |     +-----+

   The assignment of the index values could for example be:

           ifIndex  Description
           1        Ethernet
           2        Line#A Router
           3        Line#B Router
           4        Line#C Router
           5        Line#D Router
           6        Line#A CSU Router
           7        Line#B CSU Router
           8        Line#C CSU Router
           9        Line#D CSU Router
           10       Line#A CSU Network
           11       Line#B CSU Network
           12       Line#C CSU Network
           13       Line#D CSU Network

   The ifStackTable is then used to show the relationships between the
   various DS1 interfaces.

           ifStackTable Entries
           HigherLayer   LowerLayer
           2             6
           3             7
           4             8
           5             9
           6             10
           7             11
           8             12
           9             13



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   If the CSU shelf is managed by itself by a local SNMP Agent, the
   situation would be identical, except the Ethernet and the 4 router
   interfaces are deleted.  Interfaces would also be numbered from 1 to
   8.

           ifIndex  Description
           1        Line#A CSU Router
           2        Line#B CSU Router
           3        Line#C CSU Router
           4        Line#D CSU Router
           5        Line#A CSU Network
           6        Line#B CSU Network
           7        Line#C CSU Network
           8        Line#D CSU Network

           ifStackTable Entries

           HigherLayer   LowerLayer
           1             5
           2             6
           3             7
           4             8

2.2.2.  Usage of ifStackTable for DS1/E1 on DS2/E2

   An example is given of how DS1/E2 interfaces are stacked on DS2/E2
   interfaces.  It is not necessary nor is it always desirable to
   represent DS2 interfaces.  If this is required, the following
   stacking should be used.  All ifTypes are ds1.  The DS2 is determined
   by examining ifSpeed or dsx1LineType.

        ifIndex  Description
        1        DS1 #1
        2        DS1 #2
        3        DS1 #3
        4        DS1 #4
        5        DS2

        ifStackTable Entries

        HigherLayer   LowerLayer
        1             5
        2             5
        3             5
        4             5






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2.2.3.  Usage of Channelization for DS3, DS1, DS0

   An example is given here to explain the channelization objects in the
   DS3, DS1, and DS0 MIBs to help the implementor use the objects
   correctly. Treatment of E3 and E1 would be similar, with the number
   of DS0s being different depending on the framing of the E1.


   Assume that a DS3 (with ifIndex 1) is Channelized into DS1s (without
   DS2s).  The object dsx3Channelization is set to enabledDs1.  There
   will be 28 DS1s in the ifTable.  Assume the entries in the ifTable
   for the DS1s are created in channel order and the ifIndex values are
   2 through 29. In the DS1 MIB, there will be an entry in the
   dsx1ChanMappingTable for each ds1.  The entries will be as follows:

           dsx1ChanMappingTable Entries

           ifIndex  dsx1Ds1ChannelNumber   dsx1ChanMappedIfIndex
           1        1                      2
           1        2                      3
           ......
           1        28                     29

   In addition, the DS1s are channelized into DS0s.  The object
   dsx1Channelization is set to enabledDS0 for each DS1.   When this
   object is set to this value, 24 DS0s are created by the agent. There
   will be 24 DS0s in the ifTable for each DS1.  If the
   dsx1Channelization is set to disabled, the 24 DS0s are destroyed.

   Assume the entries in the ifTable are created in channel order and
   the ifIndex values for the DS0s in the first DS1 are 30 through 53.
   In the DS0 MIB, there will be an entry in the dsx0ChanMappingTable
   for each DS0.  The entries will be as follows:

           dsx0ChanMappingTable Entries

           ifIndex   dsx0Ds0ChannelNumber  dsx0ChanMappedIfIndex
           2         1                     30
           2         2                     31
           ......
           2         24                    53

2.2.4.  Usage of Channelization for DS3, DS2, DS1

   An example is given here to explain the channelization objects in the
   DS3 and DS1 MIBs to help the implementor use the objects correctly.





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   Assume that a DS3 (with ifIndex 1) is Channelized into DS2s.  The
   object dsx3Channelization is set to enabledDs2.  There will be 7 DS2s
   (ifType of DS1) in the ifTable.  Assume the entries in the ifTable
   for the DS2s are created in channel order and the ifIndex values are
   2 through 8. In the DS1 MIB, there will be an entry in the
   dsx1ChanMappingTable for each DS2.  The entries will be as follows:

           dsx1ChanMappingTable Entries

           ifIndex  dsx1Ds1ChannelNumber   dsx1ChanMappedIfIndex
           1        1                      2
           1        2                      3
           ......
           1        7                      8

   In addition, the DS2s are channelized into DS1s.  The object
   dsx1Channelization is set to enabledDS1 for each DS2.  There will be
   4 DS1s in the ifTable for each DS2.  Assume the entries in the
   ifTable are created in channel order and the ifIndex values for the
   DS1s in the first DS2 are 9 through 12, then 13 through 16 for the
   second DS2, and so on.  In the DS1 MIB, there will be an entry in the
   dsx1ChanMappingTable for each DS1.  The entries will be as follows:

           dsx1ChanMappingTable Entries

           ifIndex   dsx1Ds1ChannelNumber  dsx1ChanMappedIfIndex
           2         1                     9
           2         2                     10
           2         3                     11
           2         4                     12
           3         1                     13
           3         2                     14
           ...
           8         4                     36


2.2.5.  Usage of Loopbacks

   This section discusses the behaviour of objects related to loopbacks.

   The object dsx1LoopbackConfig represents the desired state of
   loopbacks on this interface.  Using this object a Manager can
   request:
       LineLoopback
       PayloadLoopback (if ESF framing)
       InwardLoopback
       DualLoopback (Line + Inward)
       NoLoopback



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   The remote end can also request loopbacks either through the FDL
   channel if ESF or inband if D4.  The loopbacks that can be request
   this way are:
       LineLoopback
       PayloadLoopback (if ESF framing)
       NoLoopback

   To model the current state of loopbacks on a DS1 interface, the
   object dsx1LoopbackStatus defines which loopback is currently applies
   to an interface.  This objects, which is a bitmap, will have bits
   turned on which reflect the currently active loopbacks on the
   interface as well as the source of those loopbacks.

   The following restrictions/rules apply to loopbacks:

   The far end cannot undo loopbacks set by a manager.

   A manager can undo loopbacks set by the far end.

   Both a line loopback and an inward loopback can be set at the same
   time.  Only these two loopbacks can co-exist and either one may be
   set by the manager or the far end.  A LineLoopback request from the
   far end is incremental to an existing Inward loopback established by
   a manager.  When a NoLoopback is received from the far end in this
   case, the InwardLoopback remains in place.

2.3.  Objectives of this MIB Module

   There are numerous things that could be included in a MIB for DS1
   signals:  the management of multiplexors, CSUs, DSUs, and the like.
   The intent of this document is to facilitate the common management of
   all devices with DS1, E1, DS2, or E3 interfaces.  As such, a design
   decision was made up front to very closely align the MIB with the set
   of objects that can generally be read from these types devices that
   are currently deployed.

   J2 interfaces are not supported by this MIB.

2.4.  DS1 Terminology

   The terminology used in this document to describe error conditions on
   a DS1 interface as monitored by a DS1 device are based on the late
   but not final draft of what became the ANSI T1.231 standard [11].  If
   the definition in this document does not match the definition in the
   ANSI T1.231 document, the implementer should follow the definition
   described in this document.





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2.4.1.  Error Events

   Bipolar Violation (BPV) Error Event
       A BPV error event for an AMI-coded signal is the occurrence of a
       pulse of the same polarity as the previous pulse.  (See T1.231
       Section 6.1.1.1.1) A BPV error event for a B8ZS- or HDB3- coded
       signal is the occurrence of a pulse of the same polarity as the
       previous pulse without being a part of the zero substitution
       code.

   Excessive Zeroes (EXZ) Error Event
       An Excessive Zeroes error event for an AMI-coded signal is the
       occurrence of more than fifteen contiguous zeroes.  (See T1.231
       Section 6.1.1.1.2) For a B8ZS coded signal, the defect occurs
       when more than seven contiguous zeroes are detected.

   Line Coding Violation (LCV) Error Event
       A Line Coding Violation (LCV) is the occurrence of either a
       Bipolar Violation (BPV) or Excessive Zeroes (EXZ) Error Event.
       (Also known as CV-L; See T1.231 Section 6.5.1.1)

   Path Coding Violation (PCV) Error Event
       A Path Coding Violation error event is a frame synchronization
       bit error in the D4 and E1-noCRC formats, or a CRC or frame
       synch. bit error in the ESF and E1-CRC formats. (Also known as
       CV-P; See T1.231 Section 6.5.2.1)

   Controlled Slip (CS) Error Event
       A Controlled Slip is the replication or deletion of the payload
       bits of a DS1 frame.  (See T1.231 Section 6.1.1.2.3) A Controlled
       Slip may be performed when there is a difference between the
       timing of a synchronous receiving terminal and the received
       signal.  A Controlled Slip does not cause an Out of Frame defect.

2.4.2.  Performance Defects

   Out Of Frame (OOF) Defect
       An OOF defect is the occurrence of a particular density of
       Framing Error events. (See T1.231 Section 6.1.2.2.1)

       For DS1 links, an Out of Frame defect is declared when the
       receiver detects two or more framing errors within a 3 msec
       period for ESF signals and 0.75 msec for D4 signals, or two or
       more errors out of five or fewer consecutive framing-bits.

       For E1 links, an Out Of Frame defect is declared when three
       consecutive frame alignment signals have been received with an
       error (see G.706 Section 4.1 [26]).



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       For DS2 links, an Out of Frame defect is declared when 7 or more
       consecutive errored framing patterns (4 multiframe) are received.
       The LOF is cleared when 3 or more consecutive correct framing
       patterns are received.

       Once an Out Of Frame Defect is declared, the framer starts
       searching for a correct framing pattern.  The Out of Frame defect
       ends when the signal is in frame.

       In-frame occurs when there are fewer than two frame bit errors
       within 3 msec period for ESF signals and 0.75 msec for D4
       signals.

       For E1 links, in-frame occurs when a) in frame N the frame
       alignment signal is correct and b) in frame N+1 the frame
       alignment signal is absent (i.e., bit 2 in TS0 is a one) and c)
       in frame N+2 the frame alignment signal is present and correct.
       (See G.704 Section 4.1)

   Alarm Indication Signal (AIS) Defect
       For D4 and ESF links, the 'all ones' condition is detected at a
       DS1 line interface upon observing an unframed signal with a one's
       density of at least 99.9% present for a time equal to or greater
       than T, where 3 ms <= T <= 75 ms.  The AIS is terminated upon
       observing a signal not meeting the one's density or the unframed
       signal criteria for a period equal to or greater than than T.
       (See G.775, Section 5.4)

       For E1 links, the 'all-ones' condition is detected at the line
       interface as a string of 512 bits containing fewer than three
       zero bits (see O.162 [23] Section 3.3.2).

       For DS2 links, the DS2 AIS shall be sent from the NT1 to the user
       to indicate a loss of the 6,312 kbps frame capability on the
       network side.  The DS2 AIS is defined as a bit array of 6,312
       kbps in which all binary bits are set to '1'.

       The DS2 AIS detection and removal shall be implemented according
       to ITU-T Draft Recommendation G.775 [31] Section 5.5:
       - a DS2 AIS defect is detected when the incoming signal has two
       (2) or less ZEROs in a sequence of 3156 bits (0.5 ms).
       - a DS2 AIS defect is cleared when the incoming signal has three
       (3) or more ZEROs in a sequence of 3156 bits (0.5 ms).








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2.4.3.  Performance Parameters

   All performance parameters are accumulated in fifteen minute
   intervals and up to 96 intervals (24 hours worth) are kept by an
   agent.  Fewer than 96 intervals of data whelfill be available if the
   agent has been restarted within the last 24 hours.  In addition,
   there is a rolling 24-hour total of each performance parameter.
   Performance parameters continue to be collected when the interface is
   down.

   There is no requirement for an agent to ensure fixed relationship
   between the start of a fifteen minute interval and any wall clock;
   however some agents may align the fifteen minute intervals with
   quarter hours.

   Performance parameters are of types PerfCurrentCount,
   PerfIntervalCount and PerfTotalCount.  These textual conventions are
   all Gauge32, and they are used because it is possible for these
   objects to decrease.  Objects may decrease when Unavailable Seconds
   occurs across a fifteen minutes interval boundary. See Unavailable
   Seconds discussion later in this section.

    Line Errored Seconds (LES)
        A Line Errored Second is a second in which one or more Line Code
        Violation error events were detected. (Also known as ES-L; See
        T1.231 Section 6.5.1.2)

    Controlled Slip Seconds (CSS)
        A Controlled Slip Second is a one-second interval containing one
        or more controlled slips.  (See T1.231 Section 6.5.2.8) This is
        not incremented during an Unavailable Second.

    Errored Seconds (ES)
        For ESF and E1-CRC links an Errored Second is a second with one
        or more Path Code Violation OR one or more Out of Frame defects
        OR one or more Controlled Slip events OR a detected AIS defect.
        (See T1.231 Section 6.5.2.2 and G.826 [32] Section B.1)

        For D4 and E1-noCRC links, the presence of Bipolar Violations
        also triggers an Errored Second.

        This is not incremented during an Unavailable Second.









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    Bursty Errored Seconds (BES)
        A Bursty Errored Second (also known as Errored Second type B in
        T1.231 Section 6.5.2.4) is a second with fewer than 320 and more
        than 1 Path Coding Violation error events, no Severely Errored
        Frame defects and no detected incoming AIS defects.  Controlled
        slips are not included in this parameter.

        This is not incremented during an Unavailable Second.  It
        applies to ESF signals only.

    Severely Errored Seconds (SES)
        A Severely Errored Second for ESF signals is a second with 320
        or more Path Code Violation Error Events OR one or more Out of
        Frame defects OR a detected AIS defect. (See T1.231 Section
        6.5.2.5)

        For E1-CRC signals, a Severely Errored Second is a second with
        832 or more Path Code Violation error events OR one or more Out
        of Frame defects.

        For E1-noCRC signals, a Severely Errored Second is a 2048 LCVs
        or more.

        For D4 signals, a Severely Errored Second is a count of one-
        second intervals with Framing Error events, or an OOF defect, or
        1544 LCVs or more.

        Controlled slips are not included in this parameter.

        This is not incremented during an Unavailable Second.

    Severely Errored Framing Second (SEFS)
        An Severely Errored Framing Second is a second with one or more
        Out of Frame defects OR a detected AIS defect.  (Also known as
        SAS-P (SEF/AIS second); See T1.231 Section 6.5.2.6)

    Degraded Minutes
        A Degraded Minute is one in which the estimated error rate
        exceeds 1E-6 but does not exceed 1E-3 (see G.821 [24]).

        Degraded Minutes are determined by collecting all of the
        Available Seconds, removing any Severely Errored Seconds
        grouping the result in 60-second long groups and counting a 60-
        second long group (a.k.a., minute) as degraded if the cumulative
        errors during the seconds present in the group exceed 1E-6.
        Available seconds are merely those seconds which are not
        Unavailable as described below.




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    Unavailable Seconds (UAS)
        Unavailable Seconds (UAS) are calculated by counting the number
        of seconds that the interface is unavailable.  The DS1 interface
        is said to be unavailable from the onset of 10 contiguous SESs,
        or the onset of the condition leading to a failure (see Failure
        States).  If the condition leading to the failure was
        immediately preceded by one or more contiguous SESs, then the
        DS1 interface unavailability starts from the onset of these
        SESs.  Once unavailable, and if no failure is present, the DS1
        interface becomes available at the onset of 10 contiguous
        seconds with no SESs.  Once unavailable, and if a failure is
        present, the DS1 interface becomes available at the onset of 10
        contiguous seconds with no SESs, if the failure clearing time is
        less than or equal to 10 seconds.  If the failure clearing time
        is more than 10 seconds, the DS1 interface becomes available at
        the onset of 10 contiguous seconds with no SESs, or the onset
        period leading to the successful clearing condition, whichever
        occurs later.  With respect to the DS1 error counts, all
        counters are incremented while the DS1 interface is deemed
        available.  While the interface is deemed unavailable, the only
        count that is incremented is UASs.

        Note that this definition implies that the agent cannot
        determine until after a ten second interval has passed whether a
        given one-second interval belongs to available or unavailable
        time.  If the agent chooses to update the various performance
        statistics in real time then it must be prepared to
        retroactively reduce the ES, BES, SES, and SEFS counts by 10 and
        increase the UAS count by 10 when it determines that available
        time has been entered.  It must also be prepared to adjust the
        PCV count and the DM count as necessary since these parameters
        are not accumulated during unavailable time.  It must be
        similarly prepared to retroactively decrease the UAS count by 10
        and increase the ES, BES, and DM counts as necessary upon
        entering available time.  A special case exists when the 10
        second period leading to available or unavailable time crosses a
        900 second statistics window boundary, as the foregoing
        description implies that the ES, BES, SES, SEFS, DM, and UAS
        counts the PREVIOUS interval must be adjusted.  In this case
        successive GETs of the affected dsx1IntervalSESs and
        dsx1IntervalUASs objects will return differing values if the
        first GET occurs during the first few seconds of the window.

        The agent may instead choose to delay updates to the various
        statistics by 10 seconds in order to avoid retroactive
        adjustments to the counters.  A way to do this is sketched in
        Appendix B.




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        In any case, a linkDown trap shall be sent only after the agent
        has determined for certain that the unavailable state has been
        entered, but the time on the trap will be that of the first UAS
        (i.e., 10 seconds earlier).  A linkUp trap shall be handled
        similarly.

        According to ANSI T1.231 unavailable time begins at the _onset_
        of 10 contiguous severely errored seconds -- that is,
        unavailable time starts with the _first_ of the 10 contiguous
        SESs.  Also, while an interface is deemed unavailable all
        counters for that interface are frozen except for the UAS count.
        It follows that an implementation which strictly complies with
        this standard must _not_ increment any counters other than the
        UAS count -- even temporarily -- as a result of anything that
        happens during those 10 seconds.  Since changes in the signal
        state lag the data to which they apply by 10 seconds, an ANSI-
        compliant implementation must pass the the one-second statistics
        through a 10-second delay line prior to updating any counters.
        That can be done by performing the following steps at the end of
        each one second interval.

   i)   Read near/far end CV counter and alarm status flags from the
        hardware.

   ii)  Accumulate the CV counts for the preceding second and compare
        them to the ES and SES threshold for the layer in question.
        Update the signal state and shift the one-second CV counts and
        ES/SES flags into the 10-element delay line.  Note that far-end
        one-second statistics are to be flagged as "absent" during any
        second in which there is an incoming defect at the layer in
        question or at any lower layer.

   iii) Update the current interval statistics using the signal state
        from the _previous_ update cycle and the one-second CV counts
        and ES/SES flags shifted out of the 10-element delay line.

   This approach is further described in Appendix B.

2.4.4.  Failure States

   The following failure states are received, or detected failures, that
   are reported in the dsx1LineStatus object.  When a DS1 interface
   would, if ever, produce the conditions leading to the failure state
   is described in the appropriate specification.







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    Far End Alarm Failure
        The Far End Alarm failure is also known as "Yellow Alarm" in the
        DS1 case, "Distant Alarm" in the E1 case, and "Remote Alarm" in
        the DS2 case.

        For D4 links, the Far End Alarm failure is declared when bit 6
        of all channels has been zero for at least 335 ms and is cleared
        when bit 6 of at least one channel is non-zero for a period T,
        where T is usually less than one second and always less than 5
        seconds.  The Far End Alarm failure is not declared for D4 links
        when a Loss of Signal is detected.

        For ESF links, the Far End Alarm failure is declared if the
        Yellow Alarm signal pattern occurs in at least seven out of ten
        contiguous 16-bit pattern intervals and is cleared if the Yellow
        Alarm signal pattern does not occur in ten contiguous 16-bit
        signal pattern intervals.

        For E1 links, the Far End Alarm failure is declared when bit 3
        of time-slot zero is received set to one on two consecutive
        occasions.  The Far End Alarm failure is cleared when bit 3 of
        time-slot zero is received set to zero.

        For DS2 links, if a loss of frame alignment (LOF or LOS) and/or
        DS2 AIS condition, is detected, the RAI signal shall be
        generated and transmitted to the remote side.

        The Remote Alarm Indication(RAI) signal is defined on m-bits as
        a repetition of the 16bit sequence consisting of eight binary
        '1s' and eight binary '0s' in m-bits(1111111100000000).  When
        the RAI signal is not sent (in normal operation),the HDLC flag
        pattern (01111110) in the m-bit is sent.

        The RAI failure is detected when 16 or more consecutive RAI-
        patterns (1111111100000000) are received.  The RAI failure is
        cleared when 4 or more consecutive incorrect-RAI-patterns are
        received.

    Alarm Indication Signal (AIS) Failure
        The Alarm Indication Signal failure is declared when an AIS
        defect is detected at the input and the  AIS defect still exists
        after the Loss Of Frame failure (which is caused by the unframed
        nature of the 'all-ones' signal) is declared. The AIS failure is
        cleared when the Loss Of Frame failure is cleared.  (See T1.231
        Section 6.2.1.2.1)






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        An AIS defect at a 6312 kbit/s (G.704) interface is detected
        when the incoming signal has two {2} or less ZEROs in a sequence
        of 3156 bits (0.5ms).

        The AIS signal defect is cleared when the incoming signal has
        three {3} or more ZEROs in a sequence of 3156 bits (0.5ms).

    Loss Of Frame Failure
        For DS1 links, the Loss Of Frame failure is declared when an OOF
        or LOS  defect has persisted for T seconds, where 2 <= T <= 10.
        The Loss Of Frame failure is cleared when there have been no OOF
        or LOS defects during a period T where 0 <= T <= 20.  Many
        systems will perform "hit integration" within the period T
        before declaring or clearing the failure e.g., see TR 62411
        [25].

        For E1 links, the Loss Of Frame Failure is declared when an OOF
        defect is detected.

    Loss Of Signal Failure
        For DS1, the Loss Of Signal failure is declared upon observing
        175 +/- 75 contiguous pulse positions with no pulses of either
        positive or negative polarity.  The LOS failure is cleared upon
        observing an average pulse density of at least 12.5% over a
        period of 175 +/- 75 contiguous pulse positions starting with
        the receipt of a pulse.

        For E1 links, the Loss Of Signal failure is declared when
        greater than 10 consecutive zeroes are detected (see O.162
        Section 3.4`<.4).

        A LOS defect at 6312kbit/s interfaces is detected when the
        incoming signal has "no transitions", i.e. when the signal level
        is less than or equal to a signal level of 35dB below nominal,
        for N consecutive pulse intervals, where 10 <=N<=255.

        The LOS defect is cleared when the incoming signal has
        "transitions", i.e. when the signal level is greater than or
        equal to a signal level of 9dB below nominal, for N consecutive
        pulse intervals, where 10<=N<=255.

        A signal with "transitions" corresponds to a G.703 compliant
        signal.








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    Loopback Pseudo-Failure
        The Loopback Pseudo-Failure is declared when the near end
        equipment has placed a loopback (of any kind) on the DS1.  This
        allows a management entity to determine from one object whether
        the DS1 can be considered to be in service or not (from the
        point of view of the near end equipment).

    TS16 Alarm Indication Signal Failure
        For E1 links, the TS16 Alarm Indication Signal failure is
        declared when time-slot 16 is received as all ones for all
        frames of two consecutive multiframes (see G.732 Section 4.2.6).
        This condition is never declared for DS1.

    Loss Of MultiFrame Failure
        The Loss Of MultiFrame failure is declared when two consecutive
        multiframe alignment signals (bits 4 through 7 of TS16 of frame
        0) have been received with an error.  The Loss Of Multiframe
        failure is cleared when the first correct multiframe alignment
        signal is received.  The Loss Of Multiframe failure can only be
        declared for E1 links operating with G.732 [27] framing
        (sometimes called "Channel Associated Signalling" mode).

    Far End Loss Of Multiframe Failure
        The Far End Loss Of Multiframe failure is declared when bit 2 of
        TS16 of frame 0 is received set to one on two consecutive
        occasions.  The Far End Loss Of Multiframe failure is cleared
        when bit 2 of TS16 of frame 0 is received set to zero.  The Far
        End Loss Of Multiframe failure can only be declared for E1 links
        operating in "Channel Associated Signalling" mode. (See G.732)

    DS2 Payload AIS Failure
        The DS2 Payload AIS is detected when the incoming signal of the
        6,312 kbps frame payload [TS1-TS96] has 2 or less 0's in a
        sequence of 3072 bits (0.5ms).  The DS2 Payload AIS is cleared
        when the incoming signal of the 6,312 kbps frame payload [TS1-
        TS96] has 3 or more 0's in a sequence of 3072 bits (0.5 ms).

    DS2 Performance Threshold
        DS2 Performance Threshold Failure monitors equipment performance
        and is based on the CRC (Cyclic Redundancy Check) Procedure
        defined in G.704.

        The DS2 Performance Threshold Failure is detected when the bit
        error ratio exceeds 10^-4 (Performance Threshold), and the DS2
        Performance Threshold Failure shall be cleared when the bit
        error ratio decreased to less than 10^-6."





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2.4.5.  Other Terms

    Circuit Identifier
        This is a character string specified by the circuit vendor, and
        is useful when communicating with the vendor during the
        troubleshooting process.

    Proxy
        In this document, the word proxy is meant to indicate an
        application which receives SNMP messages and replies to them on
        behalf of the devices which implement the actual DS3/E3
        interfaces.  The proxy may have already collected the
        information about the DS3/E3 interfaces into its local database
        and may not necessarily forward the requests to the actual
        DS3/E3 interface.  It is expected in such an application that
        there are periods of time where the proxy is not communicating
        with the DS3/E3 interfaces.  In these instances the proxy will
        not necessarily have up-to-date configuration information and
        will most likely have missed the collection of some statistics
        data.  Missed statistics data collection will result in invalid
        data in the interval table.

3.  Object Definitions

     DS1-MIB DEFINITIONS ::= BEGIN

     IMPORTS
          MODULE-IDENTITY, OBJECT-TYPE,
          NOTIFICATION-TYPE, transmission         FROM SNMPv2-SMI
          DisplayString, TimeStamp, TruthValue    FROM SNMPv2-TC
          MODULE-COMPLIANCE, OBJECT-GROUP,
          NOTIFICATION-GROUP                      FROM SNMPv2-CONF
          InterfaceIndex, ifIndex                 FROM IF-MIB
          PerfCurrentCount, PerfIntervalCount,
          PerfTotalCount                          FROM PerfHist-TC-MIB;


     ds1 MODULE-IDENTITY
         LAST-UPDATED "9808011830Z"
         ORGANIZATION "IETF Trunk MIB Working Group"
         CONTACT-INFO
           "        David Fowler

            Postal: Newbridge Networks Corporation
                    600 March Road
                    Kanata, Ontario, Canada K2K 2E6

                    Tel: +1 613 591 3600



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                    Fax: +1 613 599 3667

            E-mail: davef@newbridge.com"
         DESCRIPTION
              "The MIB module to describe DS1, E1, DS2, and
               E2 interfaces objects."

         ::= { transmission 18 }

     -- note that this subsumes cept (19) and g703at2mb (67)
     -- there is no separate CEPT or G703AT2MB MIB

     -- The DS1 Near End Group

     -- The DS1 Near End Group consists of five tables:
     --    DS1 Configuration
     --    DS1 Current
     --    DS1 Interval
     --    DS1 Total
     --    DS1 Channel Table

     -- The DS1 Configuration Table

     dsx1ConfigTable OBJECT-TYPE
          SYNTAX  SEQUENCE OF Dsx1ConfigEntry
          MAX-ACCESS  not-accessible
          STATUS  current
          DESCRIPTION
                 "The DS1 Configuration table."
          ::= { ds1 6 }

     dsx1ConfigEntry OBJECT-TYPE
          SYNTAX  Dsx1ConfigEntry
          MAX-ACCESS  not-accessible
          STATUS  current
          DESCRIPTION
                 "An entry in the DS1 Configuration table."
          INDEX   { dsx1LineIndex }
          ::= { dsx1ConfigTable 1 }

     Dsx1ConfigEntry ::=
          SEQUENCE {
              dsx1LineIndex                        InterfaceIndex,
              dsx1IfIndex                          InterfaceIndex,
              dsx1TimeElapsed                      INTEGER,
              dsx1ValidIntervals                   INTEGER,
              dsx1LineType                         INTEGER,
              dsx1LineCoding                       INTEGER,



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              dsx1SendCode                         INTEGER,
              dsx1CircuitIdentifier                DisplayString,
              dsx1LoopbackConfig                   INTEGER,
              dsx1LineStatus                       INTEGER,
              dsx1SignalMode                       INTEGER,
              dsx1TransmitClockSource              INTEGER,
              dsx1Fdl                              INTEGER,
              dsx1InvalidIntervals                 INTEGER,
              dsx1LineLength                       INTEGER,
              dsx1LineStatusLastChange             TimeStamp,
              dsx1LineStatusChangeTrapEnable       INTEGER,
              dsx1LoopbackStatus                   INTEGER,
              dsx1Ds1ChannelNumber                 INTEGER,
              dsx1Channelization                   INTEGER
     }

     dsx1LineIndex OBJECT-TYPE
          SYNTAX  InterfaceIndex
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "This object should be made equal to ifIndex.  The
                 next paragraph describes its previous usage.
                 Making the object equal to ifIndex allows proper
                 use of ifStackTable and ds0/ds0bundle mibs.

                 Previously, this object is the identifier of a DS1
                 Interface on a managed device.  If there is an
                 ifEntry that is directly associated with this and
                 only this DS1 interface, it should have the same
                 value as ifIndex.  Otherwise, number the
                 dsx1LineIndices with an unique identifier
                 following the rules of choosing a number that is
                 greater than ifNumber and numbering the inside
                 interfaces (e.g., equipment side) with even
                 numbers and outside interfaces (e.g, network side)
                 with odd numbers."
          ::= { dsx1ConfigEntry 1 }

     dsx1IfIndex OBJECT-TYPE
          SYNTAX  InterfaceIndex
          MAX-ACCESS  read-only
          STATUS  deprecated
          DESCRIPTION
                 "This value for this object is equal to the value
                 of ifIndex from the Interfaces table of MIB II
                 (RFC 1213)."
          ::= { dsx1ConfigEntry 2 }



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     dsx1TimeElapsed OBJECT-TYPE
          SYNTAX  INTEGER (0..899)
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                   "The number of seconds that have elapsed since
                        the beginning of the near end current error-
                   measurement period.  If, for some reason, such
                        as an adjustment in the system's time-of-day
                        clock, the current interval exceeds the maximum
                        value, the agent will return the maximum value."

          ::= { dsx1ConfigEntry 3 }

     dsx1ValidIntervals OBJECT-TYPE
          SYNTAX  INTEGER (0..96)
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of previous near end intervals for
                 which data was collected.  The value will be
                 96 unless the interface was brought online within
                 the last 24 hours, in which case the value will be
                 the number of complete 15 minute near end
                 intervals since the interface has been online.  In
                 the case where the agent is a proxy, it is
                 possible that some intervals are unavailable.  In
                 this case, this interval is the maximum interval
                 number for which data is available."
          ::= { dsx1ConfigEntry 4 }

     dsx1LineType OBJECT-TYPE
          SYNTAX  INTEGER {
                     other(1),
                     dsx1ESF(2),
                     dsx1D4(3),
                     dsx1E1(4),
                     dsx1E1CRC(5),
                     dsx1E1MF(6),
                     dsx1E1CRCMF(7),
                     dsx1Unframed(8),
                     dsx1E1Unframed(9),
                     dsx1DS2M12(10),
                     dsx2E2(11)
                 }
          MAX-ACCESS  read-write
          STATUS  current
          DESCRIPTION



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                 "This variable indicates  the  variety  of  DS1
                 Line  implementing  this  circuit.  The type of
                 circuit affects the number of bits  per  second
                 that  the circuit can reasonably carry, as well
                 as the interpretation of the  usage  and  error
                 statistics.  The values, in sequence, describe:

                 TITLE:         SPECIFICATION:
                 dsx1ESF         Extended SuperFrame DS1 (T1.107)
                 dsx1D4          AT&T D4 format DS1 (T1.107)
                 dsx1E1          ITU-T Recommendation G.704
                                  (Table 4a)
                 dsx1E1-CRC      ITU-T Recommendation G.704
                                  (Table 4b)
                 dsxE1-MF        G.704 (Table 4a) with TS16
                                  multiframing enabled
                 dsx1E1-CRC-MF   G.704 (Table 4b) with TS16
                                  multiframing enabled
                 dsx1Unframed    DS1 with No Framing
                 dsx1E1Unframed  E1 with No Framing (G.703)
                 dsx1DS2M12      DS2 frame format (T1.107)
                 dsx1E2          E2 frame format (G.704)

                 For clarification, the capacity for each E1 type
                 is as listed below:
                 dsx1E1Unframed - E1, no framing = 32 x 64k = 2048k
                 dsx1E1 or dsx1E1CRC - E1, with framing,
                    no signalling = 31 x 64k = 1984k
                 dsx1E1MF or dsx1E1CRCMF - E1, with framing,
                    signalling = 30 x 64k = 1920k

                 For further information See ITU-T Recomm G.704"
          ::= { dsx1ConfigEntry 5 }

     dsx1LineCoding OBJECT-TYPE
          SYNTAX  INTEGER {
                     dsx1JBZS (1),
                     dsx1B8ZS (2),
                     dsx1HDB3 (3),
                     dsx1ZBTSI (4),
                     dsx1AMI (5),
                     other(6),
                     dsx1B6ZS(7)
                 }
          MAX-ACCESS  read-write
          STATUS  current
          DESCRIPTION
                 "This variable describes the variety of Zero Code



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                 Suppression used on this interface, which in turn
                 affects a number of its characteristics.

                 dsx1JBZS refers the Jammed Bit Zero Suppression,
                 in which the AT&T specification of at least one
                 pulse every 8 bit periods is literally implemented
                 by forcing a pulse in bit 8 of each channel.
                 Thus, only seven bits per channel, or 1.344 Mbps,
                 is available for data.

                 dsx1B8ZS refers to the use of a specified pattern
                 of normal bits and bipolar violations which are
                 used to replace a sequence of eight zero bits.

                 ANSI Clear Channels may use dsx1ZBTSI, or Zero
                 Byte Time Slot Interchange.

                 E1 links, with or without CRC, use dsx1HDB3 or
                 dsx1AMI.

                 dsx1AMI refers to a mode wherein no zero code
                 suppression is present and the line encoding does
                 not solve the problem directly.  In this
                 application, the higher layer must provide data
                 which meets or exceeds the pulse density
                 requirements, such as inverting HDLC data.

                 dsx1B6ZS refers to the user of a specifed pattern
                 of normal bits and bipolar violations which are
                 used to replace a sequence of six zero bits.  Used
                 for DS2."

          ::= { dsx1ConfigEntry 6 }

     dsx1SendCode OBJECT-TYPE
          SYNTAX  INTEGER {
                    dsx1SendNoCode(1),
                    dsx1SendLineCode(2),
                    dsx1SendPayloadCode(3),
                    dsx1SendResetCode(4),
                    dsx1SendQRS(5),
                    dsx1Send511Pattern(6),
                    dsx1Send3in24Pattern(7),
                    dsx1SendOtherTestPattern(8)
                    }
          MAX-ACCESS  read-write
          STATUS  current
          DESCRIPTION



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                 "This variable indicates what type of code is
                 being sent across the DS1 interface by the device.
                 Setting this variable causes the interface to send
                 the code requested.  The values mean:
           dsx1SendNoCode
                sending looped or normal data

           dsx1SendLineCode
                sending a request for a line loopback

           dsx1SendPayloadCode
                sending a request for a payload loopback

           dsx1SendResetCode
                sending a loopback termination request

           dsx1SendQRS
                sending a Quasi-Random Signal  (QRS)  test
                pattern

           dsx1Send511Pattern
                sending a 511 bit fixed test pattern

           dsx1Send3in24Pattern
                sending a fixed test pattern of 3 bits set
                in 24

           dsx1SendOtherTestPattern
                sending a test pattern  other  than  those
                described by this object"
::= { dsx1ConfigEntry 7 }

     dsx1CircuitIdentifier OBJECT-TYPE
          SYNTAX  DisplayString (SIZE (0..255))
          MAX-ACCESS  read-write
          STATUS  current
          DESCRIPTION
                 "This variable contains the transmission vendor's
                 circuit identifier, for the purpose of
                 facilitating troubleshooting."
          ::= { dsx1ConfigEntry 8 }

     dsx1LoopbackConfig OBJECT-TYPE
          SYNTAX  INTEGER {
                      dsx1NoLoop(1),
                      dsx1PayloadLoop(2),
                      dsx1LineLoop(3),
                      dsx1OtherLoop(4),



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                      dsx1InwardLoop(5),
                      dsx1DualLoop(6)
                    }
          MAX-ACCESS  read-write
          STATUS  current
          DESCRIPTION
                 "This variable represents the desired loopback
                 configuration of the DS1 interface.  Agents
                 supporting read/write access should return
                 inconsistentValue in response to a requested
                 loopback state that the interface does not
                 support.  The values mean:

                 dsx1NoLoop
                  Not in the loopback state.  A device that is not
                 capable of performing a loopback on the interface
                 shall always return this as its value.

                 dsx1PayloadLoop
                  The received signal at this interface is looped
                 through the device.  Typically the received signal
                 is looped back for retransmission after it has
                 passed through the device's framing function.

                 dsx1LineLoop
                  The received signal at this interface does not go
                 through the device (minimum penetration) but is
                 looped back out.

                 dsx1OtherLoop
                  Loopbacks that are not defined here.

                 dsx1InwardLoop
                  The transmitted signal at this interface is
                 looped back and received by the same interface.
                 What is transmitted onto the line is product
                 dependent.

                 dsx1DualLoop
                  Both dsx1LineLoop and dsx1InwardLoop will be
                 active simultaneously."
          ::= { dsx1ConfigEntry 9 }

     dsx1LineStatus OBJECT-TYPE
          SYNTAX  INTEGER (1..131071)
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION



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                 "This variable indicates the Line Status of the
                 interface.  It contains loopback, failure,
                 received 'alarm' and transmitted 'alarms
                 information.

                 The dsx1LineStatus is a bit map represented as a
                 sum, therefore, it can represent multiple failures
                 (alarms) and a LoopbackState simultaneously.

                 dsx1NoAlarm must be set if and only if no other
                 flag is set.

                 If the dsx1loopbackState bit is set, the loopback
                 in effect can be determined from the
                 dsx1loopbackConfig object.
       The various bit positions are:
      1     dsx1NoAlarm           No alarm present
      2     dsx1RcvFarEndLOF      Far end LOF (a.k.a., Yellow Alarm)
      4     dsx1XmtFarEndLOF      Near end sending LOF Indication
      8     dsx1RcvAIS            Far end sending AIS
     16     dsx1XmtAIS            Near end sending AIS
     32     dsx1LossOfFrame       Near end LOF (a.k.a., Red Alarm)
     64     dsx1LossOfSignal      Near end Loss Of Signal
    128     dsx1LoopbackState     Near end is looped
    256     dsx1T16AIS            E1 TS16 AIS
    512     dsx1RcvFarEndLOMF     Far End Sending TS16 LOMF
   1024     dsx1XmtFarEndLOMF     Near End Sending TS16 LOMF
   2048     dsx1RcvTestCode       Near End detects a test code
   4096     dsx1OtherFailure      any line status not defined here
   8192     dsx1UnavailSigState   Near End in Unavailable Signal
                                  State
  16384     dsx1NetEquipOOS       Carrier Equipment Out of Service
  32768     dsx1RcvPayloadAIS     DS2 Payload AIS
  65536     dsx1Ds2PerfThreshold  DS2 Performance Threshold
                                  Exceeded"
     ::= { dsx1ConfigEntry 10 }

     dsx1SignalMode OBJECT-TYPE
          SYNTAX  INTEGER {
                     none (1),
                     robbedBit (2),
                     bitOriented (3),
                     messageOriented (4),
                     other (5)
                 }
          MAX-ACCESS  read-write
          STATUS  current
          DESCRIPTION



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            "'none' indicates that no bits are reserved for
            signaling on this channel.

            'robbedBit' indicates that DS1 Robbed Bit  Sig-
            naling is in use.

            'bitOriented' indicates that E1 Channel  Asso-
            ciated Signaling is in use.

            'messageOriented' indicates that Common  Chan-
            nel Signaling is in use either on channel 16 of
            an E1 link or channel 24 of a DS1."
          ::= { dsx1ConfigEntry 11 }

     dsx1TransmitClockSource OBJECT-TYPE
          SYNTAX  INTEGER {
                     loopTiming(1),
                     localTiming(2),
                     throughTiming(3)
                 }
          MAX-ACCESS  read-write
          STATUS  current
          DESCRIPTION
            "The source of Transmit Clock.
             'loopTiming' indicates that the recovered re-
            ceive clock is used as the transmit clock.

             'localTiming' indicates that a local clock
            source is used or when an external clock is
            attached to the box containing the interface.

             'throughTiming' indicates that recovered re-
            ceive clock from another interface is used as
            the transmit clock."
          ::= { dsx1ConfigEntry 12 }

     dsx1Fdl OBJECT-TYPE
          SYNTAX  INTEGER (1..15)
          MAX-ACCESS  read-write
          STATUS  current
          DESCRIPTION
            "This bitmap describes the use of  the  facili-
            ties data link, and is the sum of the capabili-
            ties.  Set any bits that are appropriate:

            other(1),
            dsx1AnsiT1403(2),
            dsx1Att54016(4),



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            dsx1FdlNone(8)

             'other' indicates that a protocol  other  than
            one following is used.

             'dsx1AnsiT1403' refers to the  FDL  exchange
            recommended by ANSI.

             'dsx1Att54016' refers to ESF FDL exchanges.

             'dsx1FdlNone' indicates that the device  does
            not use the FDL."
          ::= { dsx1ConfigEntry 13 }

     dsx1InvalidIntervals OBJECT-TYPE
          SYNTAX  INTEGER (0..96)
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of intervals in the range from 0 to
                 dsx1ValidIntervals for which no data is
                 available.  This object will typically be zero
                 except in cases where the data for some intervals
                 are not available (e.g., in proxy situations)."
          ::= { dsx1ConfigEntry 14 }

     dsx1LineLength OBJECT-TYPE
          SYNTAX  INTEGER (0..64000)
          UNITS  "meters"
          MAX-ACCESS  read-write
          STATUS  current
          DESCRIPTION
                 "The length of the ds1 line in meters. This
                 objects provides information for line build out
                 circuitry.  This object is only useful if the
                 interface has configurable line build out
                 circuitry."

          ::= { dsx1ConfigEntry 15 }

     dsx1LineStatusLastChange OBJECT-TYPE
          SYNTAX  TimeStamp
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The value of MIB II's sysUpTime object at the
                 time this DS1 entered its current line status
                 state.  If the current state was entered prior to



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                 the last re-initialization of the proxy-agent,
                 then this object contains a zero value."
          ::= { dsx1ConfigEntry 16 }

     dsx1LineStatusChangeTrapEnable  OBJECT-TYPE
          SYNTAX      INTEGER {
                         enabled(1),
                         disabled(2)
                      }
          MAX-ACCESS  read-write
          STATUS      current
          DESCRIPTION
                 "Indicates whether dsx1LineStatusChange traps
                 should be generated for this interface."
          DEFVAL { disabled }
          ::= { dsx1ConfigEntry 17 }

     dsx1LoopbackStatus  OBJECT-TYPE
          SYNTAX      INTEGER (1..127)
          MAX-ACCESS  read-only
          STATUS      current
          DESCRIPTION
                 "This variable represents the current state of the
                 loopback on the DS1 interface.  It contains
                 information about loopbacks established by a
                 manager and remotely from the far end.

                 The dsx1LoopbackStatus is a bit map represented as
                 a sum, therefore is can represent multiple
                 loopbacks simultaneously.

                 The various bit positions are:
                  1  dsx1NoLoopback
                  2  dsx1NearEndPayloadLoopback
                  4  dsx1NearEndLineLoopback
                  8  dsx1NearEndOtherLoopback
                 16  dsx1NearEndInwardLoopback
                 32  dsx1FarEndPayloadLoopback
                 64  dsx1FarEndLineLoopback"

     ::= { dsx1ConfigEntry 18 }

     dsx1Ds1ChannelNumber  OBJECT-TYPE
          SYNTAX      INTEGER (0..28)
          MAX-ACCESS  read-only
          STATUS      current
          DESCRIPTION
                 "This variable represents the channel number of



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                 the DS1/E1 on its parent Ds2/E2 or DS3/E3.  A
                 value of 0 indicated this DS1/E1 does not have a
                 parent DS3/E3."

     ::= { dsx1ConfigEntry 19 }

     dsx1Channelization  OBJECT-TYPE
          SYNTAX      INTEGER {
                         disabled(1),
                         enabledDs0(2),
                         enabledDs1(3)
                      }
          MAX-ACCESS  read-write
          STATUS      current
          DESCRIPTION
                 "Indicates whether this ds1/e1 is channelized or
                 unchannelized.  The value of enabledDs0 indicates
                 that this is a DS1 channelized into DS0s.  The
                 value of enabledDs1 indicated that this is a DS2
                 channelized into DS1s.  Setting this value will
                 cause the creation or deletion of entries in the
                 ifTable for the DS0s that are within the DS1."
     ::= { dsx1ConfigEntry 20 }

     -- The DS1 Current Table
     dsx1CurrentTable OBJECT-TYPE
          SYNTAX  SEQUENCE OF Dsx1CurrentEntry
          MAX-ACCESS  not-accessible
          STATUS  current
          DESCRIPTION
                 "The DS1 current table contains various statistics
                 being collected for the current 15 minute
                 interval."
          ::= { ds1 7 }

     dsx1CurrentEntry OBJECT-TYPE
          SYNTAX  Dsx1CurrentEntry
          MAX-ACCESS  not-accessible
          STATUS  current
          DESCRIPTION
                 "An entry in the DS1 Current table."
                      INDEX   { dsx1CurrentIndex }
                      ::= { dsx1CurrentTable 1 }

     Dsx1CurrentEntry ::=
          SEQUENCE {
              dsx1CurrentIndex            InterfaceIndex,
              dsx1CurrentESs              PerfCurrentCount,



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              dsx1CurrentSESs             PerfCurrentCount,
              dsx1CurrentSEFSs            PerfCurrentCount,
              dsx1CurrentUASs             PerfCurrentCount,
              dsx1CurrentCSSs             PerfCurrentCount,
              dsx1CurrentPCVs             PerfCurrentCount,
              dsx1CurrentLESs             PerfCurrentCount,
              dsx1CurrentBESs             PerfCurrentCount,
              dsx1CurrentDMs              PerfCurrentCount,
              dsx1CurrentLCVs             PerfCurrentCount
     }

     dsx1CurrentIndex OBJECT-TYPE
          SYNTAX  InterfaceIndex
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The index value which uniquely identifies  the
                 DS1 interface to which this entry is applicable.
                 The interface identified by a particular value of
                 this index is the same interface as identified by
                 the same value as a dsx1LineIndex object
                 instance."
          ::= { dsx1CurrentEntry 1 }

     dsx1CurrentESs OBJECT-TYPE
          SYNTAX  PerfCurrentCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Errored Seconds."
          ::= { dsx1CurrentEntry 2 }

     dsx1CurrentSESs OBJECT-TYPE
          SYNTAX  PerfCurrentCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Severely Errored Seconds."
          ::= { dsx1CurrentEntry 3 }

     dsx1CurrentSEFSs OBJECT-TYPE
          SYNTAX  PerfCurrentCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Severely Errored Framing Seconds."
          ::= { dsx1CurrentEntry 4 }




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     dsx1CurrentUASs OBJECT-TYPE
          SYNTAX  PerfCurrentCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Unavailable Seconds."
          ::= { dsx1CurrentEntry 5 }

     dsx1CurrentCSSs OBJECT-TYPE
          SYNTAX  PerfCurrentCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Controlled Slip Seconds."
          ::= { dsx1CurrentEntry 6 }

     dsx1CurrentPCVs OBJECT-TYPE
          SYNTAX  PerfCurrentCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Path Coding Violations."
          ::= { dsx1CurrentEntry 7 }

     dsx1CurrentLESs OBJECT-TYPE
          SYNTAX  PerfCurrentCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Line Errored Seconds."
          ::= { dsx1CurrentEntry 8 }

     dsx1CurrentBESs OBJECT-TYPE
          SYNTAX PerfCurrentCount
          MAX-ACCESS read-only
          STATUS current
          DESCRIPTION
                 "The number of Bursty Errored Seconds."
          ::= { dsx1CurrentEntry 9 }

     dsx1CurrentDMs OBJECT-TYPE
          SYNTAX PerfCurrentCount
          MAX-ACCESS read-only
          STATUS current
          DESCRIPTION
                 "The number of Degraded Minutes."
          ::= { dsx1CurrentEntry 10 }




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     dsx1CurrentLCVs OBJECT-TYPE
          SYNTAX PerfCurrentCount
          MAX-ACCESS read-only
          STATUS current
          DESCRIPTION
                 "The number of Line Code Violations (LCVs)."
          ::= { dsx1CurrentEntry 11 }


     -- The DS1 Interval Table
     dsx1IntervalTable OBJECT-TYPE
          SYNTAX  SEQUENCE OF Dsx1IntervalEntry
          MAX-ACCESS  not-accessible
          STATUS  current
          DESCRIPTION
                 "The DS1 Interval Table contains various
                 statistics collected by each DS1 Interface over
                 the previous 24 hours of operation.  The past 24
                 hours are broken into 96 completed 15 minute
                 intervals.  Each row in this table represents one
                 such interval (identified by dsx1IntervalNumber)
                 for one specific instance (identified by
                 dsx1IntervalIndex)."
          ::= { ds1 8 }

     dsx1IntervalEntry OBJECT-TYPE
          SYNTAX  Dsx1IntervalEntry
          MAX-ACCESS  not-accessible
          STATUS  current
          DESCRIPTION
                 "An entry in the DS1 Interval table."
          INDEX   { dsx1IntervalIndex, dsx1IntervalNumber }
          ::= { dsx1IntervalTable 1 }

     Dsx1IntervalEntry ::=
          SEQUENCE {
              dsx1IntervalIndex             InterfaceIndex,
              dsx1IntervalNumber            INTEGER,
              dsx1IntervalESs               PerfIntervalCount,
              dsx1IntervalSESs              PerfIntervalCount,
              dsx1IntervalSEFSs             PerfIntervalCount,
              dsx1IntervalUASs              PerfIntervalCount,
              dsx1IntervalCSSs              PerfIntervalCount,
              dsx1IntervalPCVs              PerfIntervalCount,
              dsx1IntervalLESs              PerfIntervalCount,
              dsx1IntervalBESs              PerfIntervalCount,
              dsx1IntervalDMs               PerfIntervalCount,
              dsx1IntervalLCVs              PerfIntervalCount,



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              dsx1IntervalValidData         TruthValue
     }

     dsx1IntervalIndex OBJECT-TYPE
          SYNTAX  InterfaceIndex
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The index value which uniquely identifies the DS1
                 interface to which this entry is applicable.  The
                 interface identified by a particular value of this
                 index is the same interface as identified by the
                 same value as a dsx1LineIndex object instance."
          ::= { dsx1IntervalEntry 1 }

     dsx1IntervalNumber OBJECT-TYPE
          SYNTAX  INTEGER (1..96)
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "A number between 1 and 96, where 1 is the most
                 recently completed 15 minute interval and 96 is
                 the 15 minutes interval completed 23 hours and 45
                 minutes prior to interval 1."
          ::= { dsx1IntervalEntry 2 }

     dsx1IntervalESs OBJECT-TYPE
          SYNTAX  PerfIntervalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Errored Seconds."
          ::= { dsx1IntervalEntry 3 }

     dsx1IntervalSESs OBJECT-TYPE
          SYNTAX  PerfIntervalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Severely Errored Seconds."
          ::= { dsx1IntervalEntry 4 }

     dsx1IntervalSEFSs OBJECT-TYPE
          SYNTAX  PerfIntervalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Severely Errored Framing Seconds."



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          ::= { dsx1IntervalEntry 5 }

     dsx1IntervalUASs OBJECT-TYPE
          SYNTAX  PerfIntervalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Unavailable Seconds.  This object
                 may decrease if the occurance of unavailable
                 seconds occurs across an inteval boundary."
          ::= { dsx1IntervalEntry 6 }

     dsx1IntervalCSSs OBJECT-TYPE
          SYNTAX  PerfIntervalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Controlled Slip Seconds."
          ::= { dsx1IntervalEntry 7 }

     dsx1IntervalPCVs OBJECT-TYPE
          SYNTAX  PerfIntervalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Path Coding Violations."
          ::= { dsx1IntervalEntry 8 }

     dsx1IntervalLESs OBJECT-TYPE
          SYNTAX  PerfIntervalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Line Errored Seconds."
          ::= { dsx1IntervalEntry 9 }

     dsx1IntervalBESs OBJECT-TYPE
          SYNTAX PerfIntervalCount
          MAX-ACCESS read-only
          STATUS current
          DESCRIPTION
                 "The number of Bursty Errored Seconds."
          ::= { dsx1IntervalEntry 10 }

     dsx1IntervalDMs OBJECT-TYPE
          SYNTAX PerfIntervalCount
          MAX-ACCESS read-only
          STATUS current



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          DESCRIPTION
                 "The number of Degraded Minutes."
          ::= { dsx1IntervalEntry 11 }

     dsx1IntervalLCVs OBJECT-TYPE
          SYNTAX PerfIntervalCount
          MAX-ACCESS read-only
          STATUS current
          DESCRIPTION
                 "The number of Line Code Violations."
          ::= { dsx1IntervalEntry 12 }

     dsx1IntervalValidData OBJECT-TYPE
          SYNTAX TruthValue
          MAX-ACCESS read-only
          STATUS current
          DESCRIPTION
                 "This variable indicates if the data for this
                 interval is valid."
          ::= { dsx1IntervalEntry 13 }

     -- The DS1 Total Table
     dsx1TotalTable OBJECT-TYPE
          SYNTAX  SEQUENCE OF Dsx1TotalEntry
          MAX-ACCESS  not-accessible
          STATUS  current
          DESCRIPTION
                 "The DS1 Total Table contains the cumulative sum
                 of the various statistics for the 24 hour period
                 preceding the current interval."
          ::= { ds1 9 }

     dsx1TotalEntry OBJECT-TYPE
          SYNTAX  Dsx1TotalEntry
          MAX-ACCESS  not-accessible
          STATUS  current
          DESCRIPTION
                 "An entry in the DS1 Total table."
          INDEX   { dsx1TotalIndex }
          ::= { dsx1TotalTable 1 }

     Dsx1TotalEntry ::=
          SEQUENCE {
              dsx1TotalIndex                InterfaceIndex,
              dsx1TotalESs                  PerfTotalCount,
              dsx1TotalSESs                 PerfTotalCount,
              dsx1TotalSEFSs                PerfTotalCount,
              dsx1TotalUASs                 PerfTotalCount,



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              dsx1TotalCSSs                 PerfTotalCount,
              dsx1TotalPCVs                 PerfTotalCount,
              dsx1TotalLESs                 PerfTotalCount,
              dsx1TotalBESs                 PerfTotalCount,
              dsx1TotalDMs                  PerfTotalCount,
              dsx1TotalLCVs                 PerfTotalCount
     }

     dsx1TotalIndex OBJECT-TYPE
          SYNTAX  InterfaceIndex
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The index value which uniquely identifies the DS1
                 interface to which this entry is applicable.  The
                 interface identified by a particular value of this
                 index is the same interface as identified by the
                 same value as a dsx1LineIndex object instance."

          ::= { dsx1TotalEntry 1 }

     dsx1TotalESs OBJECT-TYPE
          SYNTAX  PerfTotalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The sum of Errored Seconds encountered by a DS1
                 interface in the previous 24 hour interval.
                 Invalid 15 minute intervals count as 0."
          ::= { dsx1TotalEntry 2 }

     dsx1TotalSESs OBJECT-TYPE
          SYNTAX  PerfTotalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Severely Errored Seconds
                 encountered by a DS1 interface in the previous 24
                 hour interval.  Invalid 15 minute intervals count
                 as 0."
          ::= { dsx1TotalEntry 3 }

     dsx1TotalSEFSs OBJECT-TYPE
          SYNTAX  PerfTotalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Severely Errored Framing Seconds



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                 encountered by a DS1 interface in the previous 24
                 hour interval.  Invalid 15 minute intervals count
                 as 0."
          ::= { dsx1TotalEntry 4 }

     dsx1TotalUASs OBJECT-TYPE
          SYNTAX  PerfTotalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Unavailable Seconds encountered by
                 a DS1 interface in the previous 24 hour interval.
                 Invalid 15 minute intervals count as 0."
          ::= { dsx1TotalEntry 5 }

     dsx1TotalCSSs OBJECT-TYPE
          SYNTAX  PerfTotalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Controlled Slip Seconds encountered
                 by a DS1 interface in the previous 24 hour
                 interval.  Invalid 15 minute intervals count as
                 0."
          ::= { dsx1TotalEntry 6 }

     dsx1TotalPCVs OBJECT-TYPE
          SYNTAX  PerfTotalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Path Coding Violations encountered
                 by a DS1 interface in the previous 24 hour
                 interval.  Invalid 15 minute intervals count as
                 0."
          ::= { dsx1TotalEntry 7 }

     dsx1TotalLESs OBJECT-TYPE
          SYNTAX  PerfTotalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Line Errored Seconds encountered by
                 a DS1 interface in the previous 24 hour interval.
                 Invalid 15 minute intervals count as 0."
          ::= { dsx1TotalEntry 8 }

     dsx1TotalBESs OBJECT-TYPE



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          SYNTAX PerfTotalCount
          MAX-ACCESS read-only
          STATUS current
          DESCRIPTION
                 "The number of Bursty Errored Seconds (BESs)
                 encountered by a DS1 interface in the previous 24
                 hour interval. Invalid 15 minute intervals count
                 as 0."
          ::= { dsx1TotalEntry 9 }

     dsx1TotalDMs OBJECT-TYPE
          SYNTAX PerfTotalCount
          MAX-ACCESS read-only
          STATUS current
          DESCRIPTION
                 "The number of Degraded Minutes (DMs) encountered
                 by a DS1 interface in the previous 24 hour
                 interval.  Invalid 15 minute intervals count as
                 0."
          ::= { dsx1TotalEntry 10 }

     dsx1TotalLCVs OBJECT-TYPE
          SYNTAX PerfTotalCount
          MAX-ACCESS read-only
          STATUS current
          DESCRIPTION
                 "The number of Line Code Violations (LCVs)
                 encountered by a DS1 interface in the current 15
                 minute interval.  Invalid 15 minute intervals
                 count as 0."
          ::= { dsx1TotalEntry 11 }

     -- The DS1 Channel Table
     dsx1ChanMappingTable OBJECT-TYPE
          SYNTAX  SEQUENCE OF Dsx1ChanMappingEntry
          MAX-ACCESS  not-accessible
          STATUS  current
          DESCRIPTION
                 "The DS1 Channel Mapping table.  This table maps a
                 DS1 channel number on a particular DS3 into an
                 ifIndex.  In the presence of DS2s, this table can
                 be used to map a DS2 channel number on a DS3 into
                 an ifIndex, or used to map a DS1 channel number on
                 a DS2 onto an ifIndex."
          ::= { ds1 16 }

     dsx1ChanMappingEntry OBJECT-TYPE
          SYNTAX  Dsx1ChanMappingEntry



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          MAX-ACCESS  not-accessible
          STATUS  current
          DESCRIPTION
                 "An entry in the DS1 Channel Mapping table.  There
                 is an entry in this table corresponding to each
                 ds1 ifEntry within any interface that is
                 channelized to the individual ds1 ifEntry level.

                 This table is intended to facilitate mapping from
                 channelized interface / channel number to DS1
                 ifEntry.  (e.g. mapping (DS3 ifIndex, DS1 Channel
                 Number) -> ifIndex)

                 While this table provides information that can
                 also be found in the ifStackTable and
                 dsx1ConfigTable, it provides this same information
                 with a single table lookup, rather than by walking
                 the ifStackTable to find the various constituent
                 ds1 ifTable entries, and testing various
                 dsx1ConfigTable entries to check for the entry
                 with the applicable DS1 channel number."
          INDEX   { ifIndex, dsx1Ds1ChannelNumber }
          ::= { dsx1ChanMappingTable 1 }

     Dsx1ChanMappingEntry ::=
          SEQUENCE {
              dsx1ChanMappedIfIndex  InterfaceIndex
     }


     dsx1ChanMappedIfIndex OBJECT-TYPE
          SYNTAX  InterfaceIndex
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "This object indicates the ifIndex value assigned
                 by the agent for the individual ds1 ifEntry that
                 corresponds to the given DS1 channel number
                 (specified by the INDEX element
                 dsx1Ds1ChannelNumber) of the given channelized
                 interface (specified by INDEX element ifIndex)."
          ::= { dsx1ChanMappingEntry 1 }

     -- The DS1 Far End Current Table

     dsx1FarEndCurrentTable OBJECT-TYPE
          SYNTAX  SEQUENCE OF Dsx1FarEndCurrentEntry
          MAX-ACCESS  not-accessible



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          STATUS  current
          DESCRIPTION
                 "The DS1 Far End Current table contains various
                 statistics being collected for the current 15
                 minute interval.  The statistics are collected
                 from the far end messages on the Facilities Data
                 Link.  The definitions are the same as described
                 for the near-end information."
          ::= { ds1 10 }

     dsx1FarEndCurrentEntry OBJECT-TYPE
          SYNTAX  Dsx1FarEndCurrentEntry
          MAX-ACCESS  not-accessible
          STATUS  current
          DESCRIPTION
                 "An entry in the DS1 Far End Current table."
          INDEX   { dsx1FarEndCurrentIndex }
          ::= { dsx1FarEndCurrentTable 1 }

     Dsx1FarEndCurrentEntry ::=
          SEQUENCE {
              dsx1FarEndCurrentIndex      InterfaceIndex,
              dsx1FarEndTimeElapsed       INTEGER,
              dsx1FarEndValidIntervals    INTEGER,
              dsx1FarEndCurrentESs        PerfCurrentCount,
              dsx1FarEndCurrentSESs       PerfCurrentCount,
              dsx1FarEndCurrentSEFSs      PerfCurrentCount,
              dsx1FarEndCurrentUASs       PerfCurrentCount,
              dsx1FarEndCurrentCSSs       PerfCurrentCount,
              dsx1FarEndCurrentLESs       PerfCurrentCount,
              dsx1FarEndCurrentPCVs       PerfCurrentCount,
              dsx1FarEndCurrentBESs       PerfCurrentCount,
              dsx1FarEndCurrentDMs        PerfCurrentCount,
              dsx1FarEndInvalidIntervals  INTEGER
     }

     dsx1FarEndCurrentIndex OBJECT-TYPE
          SYNTAX  InterfaceIndex
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The index value which uniquely identifies the DS1
                 interface to which this entry is applicable.  The
                 interface identified by a particular value of this
                 index is identical to the interface identified by
                 the same value of dsx1LineIndex."
          ::= { dsx1FarEndCurrentEntry 1 }




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     dsx1FarEndTimeElapsed OBJECT-TYPE
          SYNTAX  INTEGER (0..899)
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                      "The number of seconds that have elapsed since the
                 beginning of the far end current error-measurement
                 period.  If, for some reason, such as an
                 adjustment in the system's time-of-day clock, the
                 current interval exceeds the maximum value, the
                 agent will return the maximum value."
          ::= { dsx1FarEndCurrentEntry 2 }

     dsx1FarEndValidIntervals OBJECT-TYPE
          SYNTAX  INTEGER (0..96)
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                      "The number of previous far end intervals for
                 which data was collected.  The value will be
                 96 unless the interface was brought online within
                 the last 24 hours, in which case the value will be
                 the number of complete 15 minute far end intervals
                 since the interface has been online."
          ::= { dsx1FarEndCurrentEntry 3 }

     dsx1FarEndCurrentESs OBJECT-TYPE
          SYNTAX  PerfCurrentCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Far End Errored Seconds."
          ::= { dsx1FarEndCurrentEntry 4 }

     dsx1FarEndCurrentSESs OBJECT-TYPE
          SYNTAX  PerfCurrentCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Far End Severely Errored Seconds."

          ::= { dsx1FarEndCurrentEntry 5 }

     dsx1FarEndCurrentSEFSs OBJECT-TYPE
          SYNTAX  PerfCurrentCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION



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                 "The number of Far End Severely Errored Framing
                 Seconds."
          ::= { dsx1FarEndCurrentEntry 6 }

     dsx1FarEndCurrentUASs OBJECT-TYPE
          SYNTAX  PerfCurrentCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Unavailable Seconds."
          ::= { dsx1FarEndCurrentEntry 7 }

     dsx1FarEndCurrentCSSs OBJECT-TYPE
          SYNTAX  PerfCurrentCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Far End Controlled Slip Seconds."
          ::= { dsx1FarEndCurrentEntry 8 }

     dsx1FarEndCurrentLESs OBJECT-TYPE
          SYNTAX  PerfCurrentCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Far End Line Errored Seconds."
          ::= { dsx1FarEndCurrentEntry 9 }

     dsx1FarEndCurrentPCVs OBJECT-TYPE
          SYNTAX  PerfCurrentCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Far End Path Coding Violations."
          ::= { dsx1FarEndCurrentEntry 10 }

     dsx1FarEndCurrentBESs OBJECT-TYPE
          SYNTAX PerfCurrentCount
          MAX-ACCESS read-only
          STATUS current
          DESCRIPTION
                 "The number of Far End Bursty Errored Seconds."
          ::= { dsx1FarEndCurrentEntry 11 }

     dsx1FarEndCurrentDMs OBJECT-TYPE
          SYNTAX PerfCurrentCount
          MAX-ACCESS read-only
          STATUS current



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          DESCRIPTION
                 "The number of Far End Degraded Minutes."
          ::= { dsx1FarEndCurrentEntry 12 }

     dsx1FarEndInvalidIntervals OBJECT-TYPE
          SYNTAX  INTEGER (0..96)
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of intervals in the range from 0 to
                 dsx1FarEndValidIntervals for which no data is
                 available.  This object will typically be zero
                 except in cases where the data for some intervals
                 are not available (e.g., in proxy situations)."
          ::= { dsx1FarEndCurrentEntry 13 }

     -- The DS1 Far End Interval Table
     dsx1FarEndIntervalTable OBJECT-TYPE
          SYNTAX  SEQUENCE OF Dsx1FarEndIntervalEntry
          MAX-ACCESS  not-accessible
          STATUS  current
          DESCRIPTION
                 "The DS1 Far End Interval Table contains various
                 statistics collected by each DS1 interface over
                 the previous 24 hours of operation.  The past 24
                 hours are broken into 96 completed 15 minute
                 intervals. Each row in this table represents one
                 such interval (identified by
                 dsx1FarEndIntervalNumber) for one specific
                 instance (identified by dsx1FarEndIntervalIndex)."
          ::= { ds1 11 }

     dsx1FarEndIntervalEntry OBJECT-TYPE
          SYNTAX  Dsx1FarEndIntervalEntry
          MAX-ACCESS  not-accessible
          STATUS  current
          DESCRIPTION
                 "An entry in the DS1 Far End Interval table."

          INDEX   { dsx1FarEndIntervalIndex,
                    dsx1FarEndIntervalNumber }
          ::= { dsx1FarEndIntervalTable 1 }

     Dsx1FarEndIntervalEntry ::=
          SEQUENCE {
              dsx1FarEndIntervalIndex       InterfaceIndex,
              dsx1FarEndIntervalNumber      INTEGER,
              dsx1FarEndIntervalESs         PerfIntervalCount,



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              dsx1FarEndIntervalSESs        PerfIntervalCount,
              dsx1FarEndIntervalSEFSs       PerfIntervalCount,
              dsx1FarEndIntervalUASs        PerfIntervalCount,
              dsx1FarEndIntervalCSSs        PerfIntervalCount,
              dsx1FarEndIntervalLESs        PerfIntervalCount,
              dsx1FarEndIntervalPCVs        PerfIntervalCount,
              dsx1FarEndIntervalBESs        PerfIntervalCount,
              dsx1FarEndIntervalDMs         PerfIntervalCount,
              dsx1FarEndIntervalValidData   TruthValue
     }

     dsx1FarEndIntervalIndex OBJECT-TYPE
          SYNTAX  InterfaceIndex
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The index value which uniquely identifies the DS1
                 interface to which this entry is applicable.  The
                 interface identified by a particular value of this
                 index is identical to the interface identified by
                 the same value of dsx1LineIndex."
          ::= { dsx1FarEndIntervalEntry 1 }

     dsx1FarEndIntervalNumber OBJECT-TYPE
          SYNTAX  INTEGER (1..96)
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "A number between 1 and 96, where 1 is the most
                 recently completed 15 minute interval and 96 is
                 the 15 minutes interval completed 23 hours and 45
                 minutes prior to interval 1."
          ::= { dsx1FarEndIntervalEntry 2 }

     dsx1FarEndIntervalESs OBJECT-TYPE
          SYNTAX  PerfIntervalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Far End Errored Seconds."
          ::= { dsx1FarEndIntervalEntry 3 }

     dsx1FarEndIntervalSESs OBJECT-TYPE
          SYNTAX  PerfIntervalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Far End Severely Errored Seconds."



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          ::= { dsx1FarEndIntervalEntry 4 }

     dsx1FarEndIntervalSEFSs OBJECT-TYPE
          SYNTAX  PerfIntervalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Far End Severely Errored Framing
                 Seconds."
          ::= { dsx1FarEndIntervalEntry 5 }

     dsx1FarEndIntervalUASs OBJECT-TYPE
          SYNTAX  PerfIntervalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Unavailable Seconds."
          ::= { dsx1FarEndIntervalEntry 6 }

     dsx1FarEndIntervalCSSs OBJECT-TYPE
          SYNTAX  PerfIntervalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Far End Controlled Slip Seconds."
          ::= { dsx1FarEndIntervalEntry 7 }

     dsx1FarEndIntervalLESs OBJECT-TYPE
          SYNTAX  PerfIntervalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Far End Line Errored Seconds."

          ::= { dsx1FarEndIntervalEntry 8 }

     dsx1FarEndIntervalPCVs OBJECT-TYPE
          SYNTAX  PerfIntervalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Far End Path Coding Violations."
          ::= { dsx1FarEndIntervalEntry 9 }

     dsx1FarEndIntervalBESs OBJECT-TYPE
          SYNTAX PerfIntervalCount
          MAX-ACCESS read-only
          STATUS current



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          DESCRIPTION
                 "The number of Far End Bursty Errored Seconds."
          ::= { dsx1FarEndIntervalEntry 10 }

     dsx1FarEndIntervalDMs OBJECT-TYPE
          SYNTAX PerfIntervalCount
          MAX-ACCESS read-only
          STATUS current
          DESCRIPTION
                 "The number of Far End Degraded Minutes."
          ::= { dsx1FarEndIntervalEntry 11 }

     dsx1FarEndIntervalValidData OBJECT-TYPE
          SYNTAX TruthValue
          MAX-ACCESS read-only
          STATUS current
          DESCRIPTION
                      "This variable indicates if the data for this
                 interval is valid."
          ::= { dsx1FarEndIntervalEntry 12 }

     -- The DS1 Far End Total Table

     dsx1FarEndTotalTable OBJECT-TYPE
          SYNTAX  SEQUENCE OF Dsx1FarEndTotalEntry
          MAX-ACCESS  not-accessible
          STATUS  current
          DESCRIPTION
                 "The DS1 Far End Total Table contains the
                 cumulative sum of the various statistics for the
                 24 hour period preceding the current interval."
          ::= { ds1 12 }

     dsx1FarEndTotalEntry OBJECT-TYPE
          SYNTAX  Dsx1FarEndTotalEntry
          MAX-ACCESS  not-accessible
          STATUS  current
          DESCRIPTION
                 "An entry in the DS1 Far End Total table."
          INDEX   { dsx1FarEndTotalIndex }
          ::= { dsx1FarEndTotalTable 1 }

     Dsx1FarEndTotalEntry ::=
          SEQUENCE {
              dsx1FarEndTotalIndex          InterfaceIndex,
              dsx1FarEndTotalESs            PerfTotalCount,
              dsx1FarEndTotalSESs           PerfTotalCount,
              dsx1FarEndTotalSEFSs          PerfTotalCount,



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              dsx1FarEndTotalUASs           PerfTotalCount,
              dsx1FarEndTotalCSSs           PerfTotalCount,
              dsx1FarEndTotalLESs           PerfTotalCount,
              dsx1FarEndTotalPCVs           PerfTotalCount,
              dsx1FarEndTotalBESs           PerfTotalCount,
              dsx1FarEndTotalDMs            PerfTotalCount
     }

     dsx1FarEndTotalIndex OBJECT-TYPE
          SYNTAX  InterfaceIndex
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The index value which uniquely identifies the DS1
                 interface to which this entry is applicable.  The
                 interface identified by a particular value of this
                 index is identical to the interface identified by
                 the same value of dsx1LineIndex."

          ::= { dsx1FarEndTotalEntry 1 }

     dsx1FarEndTotalESs OBJECT-TYPE
          SYNTAX  PerfTotalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Far End Errored Seconds encountered
                 by a DS1 interface in the previous 24 hour
                 interval.  Invalid 15 minute intervals count as
                 0."
          ::= { dsx1FarEndTotalEntry 2 }

     dsx1FarEndTotalSESs OBJECT-TYPE
          SYNTAX  PerfTotalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Far End Severely Errored Seconds
                 encountered by a DS1 interface in the previous 24
                 hour interval.  Invalid 15 minute intervals count
                 as 0."
          ::= { dsx1FarEndTotalEntry 3 }

     dsx1FarEndTotalSEFSs OBJECT-TYPE
          SYNTAX  PerfTotalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION



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                 "The number of Far End Severely Errored Framing
                 Seconds encountered by a DS1 interface in the
                 previous 24 hour interval. Invalid 15 minute
                 intervals count as 0."
          ::= { dsx1FarEndTotalEntry 4 }

     dsx1FarEndTotalUASs OBJECT-TYPE
          SYNTAX  PerfTotalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Unavailable Seconds encountered by
                 a DS1 interface in the previous 24 hour interval.
                 Invalid 15 minute intervals count as 0."
          ::= { dsx1FarEndTotalEntry 5 }

     dsx1FarEndTotalCSSs OBJECT-TYPE
          SYNTAX  PerfTotalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Far End Controlled Slip Seconds
                 encountered by a DS1 interface in the previous 24
                 hour interval.  Invalid 15 minute intervals count
                 as 0."
          ::= { dsx1FarEndTotalEntry 6 }

     dsx1FarEndTotalLESs OBJECT-TYPE
          SYNTAX  PerfTotalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Far End Line Errored Seconds
                 encountered by a DS1 interface in the previous 24
                 hour interval.  Invalid 15 minute intervals count
                 as 0."
          ::= { dsx1FarEndTotalEntry 7 }

     dsx1FarEndTotalPCVs OBJECT-TYPE
          SYNTAX  PerfTotalCount
          MAX-ACCESS  read-only
          STATUS  current
          DESCRIPTION
                 "The number of Far End Path Coding Violations
                 reported via the far end block error count
                 encountered by a DS1 interface in the previous 24
                 hour interval.  Invalid 15 minute intervals count
                 as 0."



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          ::= { dsx1FarEndTotalEntry 8 }

     dsx1FarEndTotalBESs OBJECT-TYPE
          SYNTAX PerfTotalCount
          MAX-ACCESS read-only
          STATUS current
          DESCRIPTION
                 "The number of Bursty Errored Seconds (BESs)
                 encountered by a DS1 interface in the previous 24
                 hour interval. Invalid 15 minute intervals count
                 as 0."
          ::= { dsx1FarEndTotalEntry 9 }


     dsx1FarEndTotalDMs OBJECT-TYPE
          SYNTAX PerfTotalCount
          MAX-ACCESS read-only
          STATUS current
          DESCRIPTION
                 "The number of Degraded Minutes (DMs) encountered
                 by a DS1 interface in the previous 24 hour
                 interval.  Invalid 15 minute intervals count as
                 0."
          ::= { dsx1FarEndTotalEntry 10 }

     -- The DS1 Fractional Table
     dsx1FracTable OBJECT-TYPE
          SYNTAX  SEQUENCE OF Dsx1FracEntry
          MAX-ACCESS  not-accessible
          STATUS  deprecated
          DESCRIPTION
                 "This table is deprecated in favour of using
                 ifStackTable.

                 The table was mandatory for systems dividing a DS1
                 into channels containing different data streams
                 that are of local interest.  Systems which are
                 indifferent to data content, such as CSUs, need
                 not implement it.

                 The DS1 fractional table identifies which DS1
                 channels associated with a CSU are being used to
                 support a logical interface, i.e., an entry in the
                 interfaces table from the Internet-standard MIB.

                 For example, consider an application managing a
                 North American ISDN Primary Rate link whose
                 division is a 384 kbit/s H1 _B_ Channel for Video,



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                 a second H1 for data to a primary routing peer,
                 and 12 64 kbit/s H0 _B_ Channels. Consider that
                 some subset of the H0 channels are used for voice
                 and the remainder are available for dynamic data
                 calls.

                 We count a total of 14 interfaces multiplexed onto
                 the DS1 interface. Six DS1 channels (for the sake
                 of the example, channels 1..6) are used for Video,
                 six more (7..11 and 13) are used for data, and the
                 remaining 12 are are in channels 12 and 14..24.

                 Let us further imagine that ifIndex 2 is of type
                 DS1 and refers to the DS1 interface, and that the
                 interfaces layered onto it are numbered 3..16.

                 We might describe the allocation of channels, in
                 the dsx1FracTable, as follows:
               dsx1FracIfIndex.2. 1 = 3  dsx1FracIfIndex.2.13 = 4
               dsx1FracIfIndex.2. 2 = 3  dsx1FracIfIndex.2.14 = 6
               dsx1FracIfIndex.2. 3 = 3  dsx1FracIfIndex.2.15 = 7
               dsx1FracIfIndex.2. 4 = 3  dsx1FracIfIndex.2.16 = 8
               dsx1FracIfIndex.2. 5 = 3  dsx1FracIfIndex.2.17 = 9
               dsx1FracIfIndex.2. 6 = 3  dsx1FracIfIndex.2.18 = 10
               dsx1FracIfIndex.2. 7 = 4  dsx1FracIfIndex.2.19 = 11
               dsx1FracIfIndex.2. 8 = 4  dsx1FracIfIndex.2.20 = 12
               dsx1FracIfIndex.2. 9 = 4  dsx1FracIfIndex.2.21 = 13
               dsx1FracIfIndex.2.10 = 4  dsx1FracIfIndex.2.22 = 14
               dsx1FracIfIndex.2.11 = 4  dsx1FracIfIndex.2.23 = 15
               dsx1FracIfIndex.2.12 = 5  dsx1FracIfIndex.2.24 = 16

                 For North American (DS1) interfaces, there are 24
                 legal channels, numbered 1 through 24.

                 For G.704 interfaces, there are 31 legal channels,
                 numbered 1 through 31.  The channels (1..31)
                 correspond directly to the equivalently numbered
                 time-slots."
          ::= { ds1 13 }

     dsx1FracEntry OBJECT-TYPE
          SYNTAX  Dsx1FracEntry
          MAX-ACCESS  not-accessible
          STATUS  deprecated
          DESCRIPTION
             "An entry in the DS1 Fractional table."
         INDEX   { dsx1FracIndex, dsx1FracNumber }
         ::= { dsx1FracTable 1 }



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     Dsx1FracEntry ::=
         SEQUENCE {
             dsx1FracIndex        INTEGER,
             dsx1FracNumber       INTEGER,
             dsx1FracIfIndex      INTEGER
         }


     dsx1FracIndex OBJECT-TYPE
         SYNTAX  INTEGER (1..'7fffffff'h)
         MAX-ACCESS  read-only
         STATUS  deprecated
         DESCRIPTION
            "The index value which uniquely identifies  the
            DS1  interface  to which this entry is applicable
            The interface identified by a  particular
            value  of  this  index is the same interface as
            identified by the same value  an  dsx1LineIndex
            object instance."
        ::= { dsx1FracEntry 1 }

     dsx1FracNumber OBJECT-TYPE
         SYNTAX  INTEGER (1..31)
         MAX-ACCESS  read-only
         STATUS  deprecated
         DESCRIPTION
            "The channel number for this entry."
        ::= { dsx1FracEntry 2 }

     dsx1FracIfIndex OBJECT-TYPE
         SYNTAX  INTEGER (1..'7fffffff'h)
         MAX-ACCESS  read-write
         STATUS  deprecated
         DESCRIPTION
            "An index value that uniquely identifies an
            interface.  The interface identified by a particular
            value of this index is the same  interface
            as  identified by the same value an ifIndex
            object instance. If no interface is currently using
            a channel, the value should be zero.  If a
            single interface occupies more  than  one  time
            slot,  that ifIndex value will be found in multiple
            time slots."
        ::= { dsx1FracEntry 3 }

      -- Ds1 TRAPS

     ds1Traps OBJECT IDENTIFIER ::= { ds1 15 }



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     dsx1LineStatusChange NOTIFICATION-TYPE
         OBJECTS { dsx1LineStatus,
                   dsx1LineStatusLastChange }
         STATUS  current
         DESCRIPTION
                 "A dsx1LineStatusChange trap is sent when the
                 value of an instance dsx1LineStatus changes. It
                 can be utilized by an NMS to trigger polls.  When
                 the line status change results from a higher level
                 line status change (i.e. ds3), then no traps for
                 the ds1 are sent."
          ::= { ds1Traps 0 1 }

     -- conformance information
     ds1Conformance OBJECT IDENTIFIER ::= { ds1 14 }

     ds1Groups      OBJECT IDENTIFIER ::= { ds1Conformance 1 }
     ds1Compliances OBJECT IDENTIFIER ::= { ds1Conformance 2 }



     -- compliance statements

     ds1Compliance MODULE-COMPLIANCE
         STATUS  current
         DESCRIPTION
                 "The compliance statement for T1 and E1
                 interfaces."
         MODULE  -- this module
             MANDATORY-GROUPS { ds1NearEndConfigGroup,
                                ds1NearEndStatisticsGroup }

             GROUP       ds1FarEndGroup
             DESCRIPTION
                 "Implementation of this group is optional for all
                 systems that attach to a DS1 Interface."

             GROUP       ds1NearEndOptionalConfigGroup
             DESCRIPTION
                 "Implementation of this group is optional for all
                 systems that attach to a DS1 Interface."

             GROUP       ds1DS2Group
             DESCRIPTION
                 "Implementation of this group is mandatory for all
                 systems that attach to a DS2 Interface."

             GROUP       ds1TransStatsGroup



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             DESCRIPTION
                 "This group is the set of statistics appropriate
                 for all systems which attach to a DS1 Interface
                 running transparent or unFramed lineType."


             GROUP       ds1ChanMappingGroup
             DESCRIPTION
                 "This group is the set of objects for mapping a
                 DS3 Channel (ds1ChannelNumber) to ifIndex.

                 Implementation of this group is mandatory for
                 systems which support the channelization of DS3s
                 into DS1s."

             OBJECT dsx1LineType
             MIN-ACCESS read-only
             DESCRIPTION
                 "The ability to set the line type is not
                 required."

             OBJECT dsx1LineCoding
             MIN-ACCESS read-only
             DESCRIPTION
                 "The ability to set the line coding is not
                 required."

             OBJECT dsx1SendCode
             MIN-ACCESS read-only
             DESCRIPTION
                 "The ability to set the send code is not
                 required."

             OBJECT dsx1LoopbackConfig
             MIN-ACCESS read-only
             DESCRIPTION
                 "The ability to set loopbacks is not required."

             OBJECT dsx1SignalMode
             MIN-ACCESS read-only
             DESCRIPTION
                 "The ability to set the signal mode is not
                 required."

             OBJECT dsx1TransmitClockSource
             MIN-ACCESS read-only
             DESCRIPTION
                 "The ability to set the transmit clock source is



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                 not required."

             OBJECT dsx1Fdl
             MIN-ACCESS read-only
             DESCRIPTION
                 "The ability to set the FDL is not required."

             OBJECT dsx1LineLength
             MIN-ACCESS read-only
             DESCRIPTION
                 "The ability to set the line length is not
                 required."

             OBJECT dsx1Channelization
             MIN-ACCESS read-only
             DESCRIPTION
                 "The ability to set the channelization is not
                 required."
         ::= { ds1Compliances 1 }

     ds1MibT1PriCompliance MODULE-COMPLIANCE
         STATUS current
         DESCRIPTION
                 "Compliance statement for using this MIB for ISDN
                 Primary Rate interfaces on T1 lines."
         MODULE
             MANDATORY-GROUPS { ds1NearEndConfigGroup,
                                ds1NearEndStatisticsGroup }
             OBJECT dsx1LineType
                 SYNTAX INTEGER {
                     dsx1ESF(2)   -- Intl Spec would be G704(2)
                                  -- or I.431(4)
                 }
                 MIN-ACCESS read-only
                 DESCRIPTION
                     "Line type for T1 ISDN Primary Rate
                      interfaces."

             OBJECT dsx1LineCoding
                 SYNTAX INTEGER {
                     dsx1B8ZS(2)
                 }
                 MIN-ACCESS read-only
                 DESCRIPTION
                     "Type of Zero Code Suppression for
                      T1 ISDN Primary Rate interfaces."

             OBJECT dsx1SignalMode



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                 SYNTAX INTEGER {
                     none(1), -- if there is no signaling channel
                     messageOriented(4)
                 }
                 MIN-ACCESS read-only
                 DESCRIPTION
                     "Possible signaling modes for
                      T1 ISDN Primary Rate interfaces."

             OBJECT dsx1TransmitClockSource
                 SYNTAX INTEGER {
                     loopTiming(1)
                 }
                 MIN-ACCESS read-only
                 DESCRIPTION
                     "The transmit clock is derived from
                      received clock on ISDN Primary Rate
                      interfaces."

             OBJECT dsx1Fdl
                 MIN-ACCESS read-only
                 DESCRIPTION
                     "Facilities Data Link usage on T1 ISDN
                      Primary Rate interfaces.
                      Note: Eventually dsx1Att-54016(4) is to be
                            used here since the line type is ESF."

             OBJECT dsx1Channelization
                 MIN-ACCESS read-only
                 DESCRIPTION
                     "The ability to set the channelization
                      is not required."
         ::= { ds1Compliances 2 }


     ds1MibE1PriCompliance MODULE-COMPLIANCE
         STATUS current
         DESCRIPTION
                 "Compliance statement for using this MIB for ISDN
                 Primary Rate interfaces on E1 lines."
         MODULE
             MANDATORY-GROUPS { ds1NearEndConfigGroup,
                                ds1NearEndStatisticsGroup }
             OBJECT dsx1LineType
                 SYNTAX INTEGER {
                     dsx1E1CRC(5)
                 }
                 MIN-ACCESS read-only



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                 DESCRIPTION
                     "Line type for E1 ISDN Primary Rate
                      interfaces."

             OBJECT dsx1LineCoding
                 SYNTAX INTEGER {
                     dsx1HDB3(3)
                 }
                 MIN-ACCESS read-only
                 DESCRIPTION
                     "Type of Zero Code Suppression for
                      E1 ISDN Primary Rate interfaces."

             OBJECT dsx1SignalMode
                 SYNTAX INTEGER {
                     messageOriented(4)
                 }
                 MIN-ACCESS read-only
                 DESCRIPTION
                     "Signaling on E1 ISDN Primary Rate interfaces
                      is always message oriented."

             OBJECT dsx1TransmitClockSource
                 SYNTAX INTEGER {
                     loopTiming(1)
                 }
                 MIN-ACCESS read-only
                 DESCRIPTION
                     "The transmit clock is derived from received
                      clock on ISDN Primary Rate interfaces."

             OBJECT dsx1Fdl
                 MIN-ACCESS read-only
                 DESCRIPTION
                     "Facilities Data Link usage on E1 ISDN
                      Primary Rate interfaces.
                      Note: There is a 'M-Channel' in E1,
                            using National Bit Sa4 (G704,
                            Table 4a). It is used to implement
                            management features between ET
                            and NT.  This is different to
                            FDL in T1, which is used to carry
                            control signals and performance
                            data.  In E1, control and status
                            signals are carried using National
                            Bits Sa5, Sa6 and A (RAI Ind.).
                      This indicates that only the other(1) or
                      eventually the dsx1Fdl-none(8) bits should



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                      be set in this object for E1 PRI."

             OBJECT dsx1Channelization
                 MIN-ACCESS read-only
                 DESCRIPTION
                 "The ability to set the channelization is not
                 required."
         ::= { ds1Compliances 3 }


     ds1Ds2Compliance MODULE-COMPLIANCE
         STATUS current
         DESCRIPTION
                 "Compliance statement for using this MIB for DS2
                 interfaces."
         MODULE
             MANDATORY-GROUPS { ds1DS2Group }

             OBJECT dsx1Channelization
                 MIN-ACCESS read-only
                 DESCRIPTION
                 "The ability to set the channelization is not
                 required."
         ::= { ds1Compliances 4 }

     -- units of conformance

     ds1NearEndConfigGroup  OBJECT-GROUP
         OBJECTS { dsx1LineIndex,
                   dsx1TimeElapsed,
                   dsx1ValidIntervals,
                   dsx1LineType,
                   dsx1LineCoding,
                   dsx1SendCode,
                   dsx1CircuitIdentifier,
                   dsx1LoopbackConfig,
                   dsx1LineStatus,
                   dsx1SignalMode,
                   dsx1TransmitClockSource,
                   dsx1Fdl,
                   dsx1InvalidIntervals,
                   dsx1LineLength,
                   dsx1LoopbackStatus,
                   dsx1Ds1ChannelNumber,
                   dsx1Channelization }
         STATUS  current
         DESCRIPTION
                 "A collection of objects providing configuration



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                 information applicable to all DS1 interfaces."
         ::= { ds1Groups 1 }

     ds1NearEndStatisticsGroup OBJECT-GROUP
         OBJECTS { dsx1CurrentIndex,
                   dsx1CurrentESs,
                   dsx1CurrentSESs,
                   dsx1CurrentSEFSs,
                   dsx1CurrentUASs,
                   dsx1CurrentCSSs,
                   dsx1CurrentPCVs,
                   dsx1CurrentLESs,
                   dsx1CurrentBESs,
                   dsx1CurrentDMs,
                   dsx1CurrentLCVs,
                   dsx1IntervalIndex,
                   dsx1IntervalNumber,
                   dsx1IntervalESs,
                   dsx1IntervalSESs,
                   dsx1IntervalSEFSs,
                   dsx1IntervalUASs,
                   dsx1IntervalCSSs,
                   dsx1IntervalPCVs,
                   dsx1IntervalLESs,
                   dsx1IntervalBESs,
                   dsx1IntervalDMs,
                   dsx1IntervalLCVs,
                   dsx1IntervalValidData,
                   dsx1TotalIndex,
                   dsx1TotalESs,
                   dsx1TotalSESs,
                   dsx1TotalSEFSs,
                   dsx1TotalUASs,
                   dsx1TotalCSSs,
                   dsx1TotalPCVs,
                   dsx1TotalLESs,
                   dsx1TotalBESs,
                   dsx1TotalDMs,
                   dsx1TotalLCVs }
         STATUS  current
         DESCRIPTION
                 "A collection of objects providing statistics
                 information applicable to all DS1 interfaces."
         ::= { ds1Groups 2 }

     ds1FarEndGroup  OBJECT-GROUP
         OBJECTS { dsx1FarEndCurrentIndex,
                   dsx1FarEndTimeElapsed,



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                   dsx1FarEndValidIntervals,
                   dsx1FarEndCurrentESs,
                   dsx1FarEndCurrentSESs,
                   dsx1FarEndCurrentSEFSs,
                   dsx1FarEndCurrentUASs,
                   dsx1FarEndCurrentCSSs,
                   dsx1FarEndCurrentLESs,
                   dsx1FarEndCurrentPCVs,
                   dsx1FarEndCurrentBESs,
                   dsx1FarEndCurrentDMs,
                   dsx1FarEndInvalidIntervals,
                   dsx1FarEndIntervalIndex,
                   dsx1FarEndIntervalNumber,
                   dsx1FarEndIntervalESs,
                   dsx1FarEndIntervalSESs,
                   dsx1FarEndIntervalSEFSs,
                   dsx1FarEndIntervalUASs,
                   dsx1FarEndIntervalCSSs,
                   dsx1FarEndIntervalLESs,
                   dsx1FarEndIntervalPCVs,
                   dsx1FarEndIntervalBESs,
                   dsx1FarEndIntervalDMs,
                   dsx1FarEndIntervalValidData,
                   dsx1FarEndTotalIndex,
                   dsx1FarEndTotalESs,
                   dsx1FarEndTotalSESs,
                   dsx1FarEndTotalSEFSs,
                   dsx1FarEndTotalUASs,
                   dsx1FarEndTotalCSSs,
                   dsx1FarEndTotalLESs,
                   dsx1FarEndTotalPCVs,
                   dsx1FarEndTotalBESs,
                   dsx1FarEndTotalDMs }
         STATUS  current
         DESCRIPTION
                 "A collection of objects providing remote
                 configuration and statistics information."
         ::= { ds1Groups 3 }

     ds1DeprecatedGroup OBJECT-GROUP
         OBJECTS { dsx1IfIndex,
                   dsx1FracIndex,
                   dsx1FracNumber,
                   dsx1FracIfIndex }
         STATUS  deprecated
         DESCRIPTION
                 "A collection of obsolete objects that may be
                 implemented for backwards compatibility."



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         ::= { ds1Groups 4 }

     ds1NearEndOptionalConfigGroup OBJECT-GROUP
         OBJECTS { dsx1LineStatusLastChange,
                   dsx1LineStatusChangeTrapEnable }

         STATUS    current
         DESCRIPTION
                 "A collection of objects that may be implemented
                 on DS1 and DS2 interfaces."
         ::= { ds1Groups 5 }

     ds1DS2Group OBJECT-GROUP
         OBJECTS { dsx1LineIndex,
                   dsx1LineType,
                   dsx1LineCoding,
                   dsx1SendCode,
                   dsx1LineStatus,
                   dsx1SignalMode,
                   dsx1TransmitClockSource,
                   dsx1Channelization }
         STATUS   current
         DESCRIPTION
                 "A collection of objects providing information
                 about DS2 (6,312 kbps) and E2 (8,448 kbps)
                 systems."
         ::= { ds1Groups 6 }

     ds1TransStatsGroup OBJECT-GROUP
         OBJECTS { dsx1CurrentESs,
                   dsx1CurrentSESs,
                   dsx1CurrentUASs,
                   dsx1IntervalESs,
                   dsx1IntervalSESs,
                   dsx1IntervalUASs,
                   dsx1TotalESs,
                   dsx1TotalSESs,
                   dsx1TotalUASs }
         STATUS   current
         DESCRIPTION
                      "A collection of objects which are the
                 statistics which can be collected from a ds1
                 interface that is running transparent or unframed
                 lineType.  Statistics not in this list should
                 return noSuchInstance."
         ::= { ds1Groups 7 }

     ds1NearEndOptionalTrapGroup NOTIFICATION-GROUP



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         NOTIFICATIONS { dsx1LineStatusChange }
         STATUS    current
         DESCRIPTION
                 "A collection of notifications that may be
                 implemented on DS1 and DS2 interfaces."
         ::= { ds1Groups 8 }

     ds1ChanMappingGroup OBJECT-GROUP
         OBJECTS { dsx1ChanMappedIfIndex }
         STATUS    current
         DESCRIPTION
                 "A collection of objects that give an mapping of
                 DS3 Channel (ds1ChannelNumber) to ifIndex."
         ::= { ds1Groups 9 }

     END



































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4.  Appendix A - Use of dsx1IfIndex and dsx1LineIndex

   This Appendix exists to document the previous use if dsx1IfIndex and
   dsx1LineIndex and to clarify the relationship of dsx1LineIndex as
   defined in rfc1406 with the dsx1LineIndex as defined in this
   document.

   The following shows the old and new definitions and the relationship:

   [New Definition]: "This object should be made equal to ifIndex.  The
   next paragraph describes its previous usage.  Making the object equal
   to ifIndex allows proper use of ifStackTable and ds0/ds0bundle mibs.

   [Old Definition]: "This object is the identifier of a DS1 Interface
   on a managed device.  If there is an ifEntry that is directly
   associated with this and only this DS1 interface, it should have the
   same value as ifIndex.  Otherwise, number the dsx1LineIndices with an
   unique identifier following the rules of choosing a number that is
   greater than ifNumber and numbering the inside interfaces (e.g.,
   equipment side) with even numbers and outside interfaces (e.g,
   network side) with odd numbers."

   When the "Old Definition" was created, it was described this way to
   allow a manager to treat the value _as if_ it were and ifIndex, i.e.
   the value would either be:  1) an ifIndex value or 2) a value that
   was guaranteed to be different from all valid ifIndex values.

   The new definition is a subset of that definition, i.e. the value is
   always an ifIndex value.

   The following is Section 3.1 from rfc1406:

   Different physical configurations for the support of SNMP with DS1
   equipment exist. To accommodate these scenarios, two different
   indices for DS1 interfaces are introduced in this MIB.  These indices
   are dsx1IfIndex and dsx1LineIndex.

   External interface scenario: the SNMP Agent represents all managed
   DS1 lines as external interfaces (for example, an Agent residing on
   the device supporting DS1 interfaces directly):

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

      ifIndex=dsx1IfIndex=dsx1LineIndex for all interfaces.






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   The dsx1IfIndex column of the DS1 Configuration table relates each
   DS1 interface to its corresponding interface (ifIndex) in the
   Internet-standard MIB (MIB-II STD 17, RFC1213).

   External&Internal interface scenario: the SNMP Agents resides on an
   host external from the device supporting DS1 interfaces (e.g., a
   router). The Agent represents both the host and the DS1 device.  The
   index dsx1LineIndex is used to not only represent the DS1 interfaces
   external from the host/DS1-device combination, but also the DS1
   interfaces connecting the host and the DS1 device.  The index
   dsx1IfIndex 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:


         +-----+
   |     |     |
   |     |     |               +---------------------+
   |E    |     |  1.544  MBPS  |              Line#A | DS1 Link
   |t    |  R  |---------------+ - - - - -  - - -  - +------>
   |h    |     |               |                     |
   |e    |  O  |  1.544  MBPS  |              Line#B | DS1 Link
   |r    |     |---------------+ - - - - - - - - - - +------>
   |n    |  U  |               |  CSU Shelf          |
   |e    |     |  1.544  MBPS  |              Line#C | DS1 Link
   |t    |  T  |---------------+ - - - -- -- - - - - +------>
   |     |     |               |                     |
   |-----|  E  |  1.544  MBPS  |              Line#D | DS1 Link
   |     |     |---------------+ -  - - - -- - - - - +------>
   |     |  R  |               |_____________________|
   |     |     |
   |     +-----+

   The assignment of the index values could for example be:

           ifIndex (= dsx1IfIndex)                     dsx1LineIndex
                   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





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                   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 dsx1LineIndex:  the dsx1LineIndex identifies a DS1
   Interface on a managed device.  If there is an ifEntry that is
   directly associated with this and only this DS1 interface, it should
   have the same value as ifIndex.  Otherwise, number the
   dsx1LineIndices 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:

           ifIndex (= dsx1IfIndex)                      dsx1LineIndex
                   1      Line#A     Network Side            1
                   2      Line#A     RouterSide              2
                   3      Line#B     Network Side            3
                   4      Line#B     RouterSide              4
                   5      Line#C     Network Side            5
                   6      Line#C     Router Side             6
                   7      Line#D     Network Side            7
                   8      Line#D     Router Side             8

























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5.  Appendix B - The delay approach to Unavialable Seconds.

   This procedure is illustrated below for a DS1 ESF interface.  Similar
   rules would apply for other DS1, DS2, and E1 interface variants.  The
   procedure guarantees that the statistical counters are correctly
   updated at all times, although they lag real time by 10 seconds.  At
   the end of each 15 minutes interval the current interval counts are
   transferred to the  most recent interval entry and each interval is
   shifted up by one position, with the oldest being discarded if
   necessary in order to make room.  The current interval counts then
   start over from zero.  Note, however, that the signal state
   calculation does not start afresh at each interval boundary;  rather,
   signal state information is retained across interval boundaries.

+---------------------------------------------------------------------+
|               READ COUNTERS & STATUS INFO FROM HARDWARE             |
|                                                                     |
| BPV EXZ LOS FE CRC CS AIS SEF OOF LOF       RAI G1-G6 SE FE LV SL   |
+---------------------------------------------------------------------+
   |   |   |   |  |   |  |   |   |   |         |    |    |  |  |  |
   |   |   |   |  |   |  |   |   |   |         |    |    |  |  |  |
   V   V   V   V  V   V  V   V   V   V         V    V    V  V  V  V
+---------------------------------------------------------------------+
|    ACCUM ONE-SEC STATS, CHK ERR THRESHOLDS, & UPDT SIGNAL STATE     |
|                                                                     |
|  |<---------- NEAR END ----------->|    |<-------- FAR END ------>| |
|                                                                     |
|  LCV LES PCV ES CSS BES SES SEFS A/U    PCV ES CSS BES SES SEFS A/U |
+---------------------------------------------------------------------+
    |   |   |  |   |   |   |   |    |      |  |   |   |   |   |    |
    |   |   |  |   |   |   |   |    |      |  |   |   |   |   |    |
    V   V   V  V   V   V   V   V    |      V  V   V   V   V   V    |
 +------------------------------+   |    +----------------------+  |
 |         ONE-SEC DELAY        |   |    |    ONE-SEC DELAY     |  |
 |           (1 OF 10)          |   |    |      (1 OF 10)       |  |
 +------------------------------+   |    +----------------------+  |
   |   |   |  |   |   |   |   |     |      |  |   |   |   |   |    |
   /   /   /  /   /   /   /   /     /      /  /   /   /   /   /    /
   |   |   |  |   |   |   |   |     |      |  |   |   |   |   |    |
   V   V   V  V   V   V   V   V     |      V  V   V   V   V   V    |
 +------------------------------+   |    +----------------------+  |
 |         ONE-SEC DELAY        |   |    |    ONE-SEC DELAY     |  |
 |           (10 OF 10)         |   |    |      (10 OF 10)      |  |
 +------------------------------+   |    +----------------------+  |
   |   |   |  |   |   |   |   |     |      |  |   |   |   |   |    |
   V   V   V  V   V   V   V   V     V      V  V   V   V   V   V    V





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+---------------------------------------------------------------------+
|                    UPDATE STATISTICS COUNTERS                       |
|                                                                     |
|<-------------- NEAR END ----------->| |<--------- FAR END --------->|
|                                                                     |
|LCV LES PCV ES CSS BES SES SEFS UAS DM PCV ES CSS BES SES SEFS UAS DM|
+---------------------------------------------------------------------+

   Note that if such a procedure is adopted there is no current interval
   data for the first ten seconds after a system comes up.
   noSuchInstance must be returned if a management station attempts to
   access the current interval counters during this time.

   It is an implementation-specific matter whether an agent assumes that
   the initial state of the interface is available or unavailable.

6.  Intellectual Property

   The IETF takes no position regarding the validity or scope of any
   intellectual property or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; neither does it represent that it
   has made any effort to identify any such rights.  Information on the
   IETF's procedures with respect to rights in standards-track and
   standards-related documentation can be found in BCP-11.  Copies of
   claims of rights made available for publication and any assurances of
   licenses to be made available, or the result of an attempt made to
   obtain a general license or permission for the use of such
   proprietary rights by implementors or users of this specification can
   be obtained from the IETF Secretariat.

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights which may cover technology that may be required to practice
   this standard.  Please address the information to the IETF Executive
   Director.

7.  Acknowledgments

   This document was produced by the Trunk MIB Working Group.










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8.  References

   [1]  Harrington, D., Presuhn, R. and B. Wijnen, "An Architecture for
        Describing SNMP Management Frameworks", RFC 2271, January 1998.

   [2]  Rose, M. and K. McCloghrie, "Structure and Identification of
        Management Information for TCP/IP-based Internets", STD 16, RFC
        1155, May 1990.

   [3]  Rose, M. and K. McCloghrie, "Concise MIB Definitions", STD 16,
        RFC 1212, March 1991.

   [4]  Rose, M., "A Convention for Defining Traps for use with the
        SNMP", RFC 1215, March 1991.

   [5]  Case, J., McCloghrie, K., Rose, M. and S. Waldbusser, "Structure
        of Management Information for Version 2 of the Simple Network
        Management Protocol (SNMPv2)", RFC 1902, January 1996.

   [6]  Case, J., McCloghrie, K., Rose, M. and S. Waldbusser, "Textual
        Conventions for Version 2 of the Simple Network Management
        Protocol (SNMPv2)", RFC 1903, January 1996.

   [7]  Case, J., McCloghrie, K., Rose, M. and S. Waldbusser,
        "Conformance Statements for Version 2 of the Simple Network
        Management Protocol (SNMPv2)", RFC 1904, January 1996.

   [8]  Case, J., Fedor, M., Schoffstall, M. and J. Davin, "Simple
        Network Management Protocol", STD 15, RFC 1157, May 1990.

   [9]  Case, J., McCloghrie, K., Rose, M. and S. Waldbusser,
        "Introduction to Community-based SNMPv2", RFC 1901, January
        1996.

   [10] Case, J., McCloghrie, K., Rose, M. and S. Waldbusser, "Transport
        Mappings for Version 2 of the Simple Network Management Protocol
        (SNMPv2)", RFC 1906, January 1996.

   [11] Case, J., Harrington D., Presuhn R. and B. Wijnen, "Message
        Processing and Dispatching for the Simple Network Management
        Protocol (SNMP)", RFC 2272, January 1998.

   [12] Blumenthal, U. and B. Wijnen, "User-based Security Model (USM)
        for version 3 of the Simple Network Management Protocol
        (SNMPv3)", RFC 2274, January 1998.






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   [13] Case, J., McCloghrie, K., Rose, M. and S. Waldbusser, "Protocol
        Operations for Version 2 of the Simple Network Management
        Protocol (SNMPv2)", RFC 1905, January 1996.

   [14] Levi, D., Meyer, P. and B. Stewart, "SNMPv3 Applications", RFC
        2273, January 1998.

   [15] Wijnen, B., Presuhn, R. and K. McCloghrie, "View-based Access
        Control Model (VACM) for the Simple Network Management Protocol
        (SNMP)", RFC 2275, January 1998.

   [16] McCloghrie, K. and F. Kastenholz, "The Interfaces Group MIB
        using SMIv2", RFC 2233, November 1997.

   [17] AT&T Information Systems, AT&T ESF DS1 Channel Service Unit
        User's Manual, 999-100-305, February 1988.

   [18] AT&T Technical Reference, Requirements for Interfacing Digital
        Terminal Equipment to Services Employing the Extended Superframe
        Format, Publication 54016, May 1988.

   [19] American National Standard for Telecommunications -- Carrier-to-
        Customer Installation - DS1 Metallic Interface, T1.403, February
        1989.

   [20] CCITT Specifications Volume III, Recommendation G.703,
        Physical/Electrical Characteristics of Hierarchical Digital
        Interfaces, April 1991.

   [21] ITU-T G.704: Synchronous frame structures used at 1544, 6312,
        2048, 8488 and 44 736 kbit/s Hierarchical Levels, July 1995.

   [22] American National Standard for Telecommunications -- Digital
        Hierarchy -- Layer 1 In-Service Digital Transmission Performace
        Monitoring, T1.231, Sept 1993.

   [23] CCITT Specifications Volume IV, Recommendation O.162, Equipment
        To Perform In Service Monitoring On 2048 kbit/s Signals, July
        1988.

   [24] CCITT Specifications Volume III, Recommendation G.821, Error
        Performance Of An International Digital Connection Forming Part
        Of An Integrated Services Digital Network, July 1988.

   [25] AT&T Technical Reference, Technical Reference 62411, ACCUNET
        T1.5 Service Description And Interface Specification, December
        1990.




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   [26] CCITT Specifications Volume III, Recommendation G.706, Frame
        Alignment and Cyclic Redundancy Check (CRC) Procedures Relating
        to Basic Frame Structures Defined in Recommendation G.704, July
        1988.

   [27] CCITT Specifications Volume III, Recommendation G.732,
        Characteristics Of Primary PCM Multiplex Equipment Operating at
        2048 kbit/s, July 1988.

   [28] Fowler, D., "Definitions of Managed Objects for the DS3/E3
        Interface Types", RFC 2496, Janaury 1999.

   [29] Brown, T., and Tesink, K., "Definitions of Managed Objects for
        the SONET/SDH Interface Type", Work in Progress.

   [30] Fowler, D., "Definitions of Managed Objects for the Ds0 and
        DS0Bundle Interface Types", RFC 2494, January 1999.

   [31] ITU-T G.775: Loss of signal (LOS) and alarm indication signal
        (AIS) defect detection and clearance criteria, May 1995.

   [32] ITU-T G.826: Error performance parameters and objectives for
        international, constant bit rate digital paths at or above the
        primary rate, November 1993.

   [33] American National Standard for Telecommunications -- Digital
        Hierarchy - Electrical Interfaces, T1.102, December 1993.

   [34] American National Standard for Telecommunications -- Digital
        Hierarchy - Format Specifications, T1.107, August 1988.

   [35] Tesink, K., "Textual Conventions for MIB Modules Using
        Performance History Based on 15 Minute Intervals", RFC XXXX,
        January 1999.

9.  Security Considerations

   SNMPv1 by itself is such an insecure environment.  Even if the
   network itself is secure (for example by using IPSec), even then,
   there is no control as to who on the secure network is allowed to
   access and GET (read) the objects in this MIB.

   It is recommended that the implementors consider the security
   features as provided by the SNMPv3 framework.  Specifically, the use
   of the User-based Security Model RFC 2274 [12] and the View-based
   Access Control Model RFC 2275 [15] is recommended.





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   It is then a customer/user responsibility to ensure that the SNMP
   entity giving access to an instance of this MIB, is properly
   configured to give access to those objects only to those principals
   (users) that have legitimate rights to access them.

   Setting any of the following objects to an inappropriate value can
   cause loss of traffic.  The definition of inappropriate varies for
   each object.  In the case of dsx1LineType, for example, both ends of
   a ds1/e1 must have the same value in order for traffic to flow.  In
   the case of dsx1SendCode and dsx1LoopbackConfig, for another example,
   traffic may stop transmitting when particular loopbacks are applied.

      dsx1LineType
      dsx1LineCoding
      dsx1SendCode
      dsx1LoopbackConfig
      dsx1SignalMode
      dsx1TransmitClockSource
      dsx1Fdl
      dsx1LineLength
      dsx1Channelization

   Setting the following object is mischevious, but not harmful to
   traffic.

      dsx1CircuitIdentifier

   Setting the following object can cause an increase in the number of
   traps received by the network management station.

      dsx1LineStatusChangeTrabEnable

10.  Author's Address

   David Fowler
   Newbridge Networks
   600 March Road
   Kanata, Ontario, Canada K2K 2E6

   Phone: (613) 599-3600, ext 6559
   EMail: davef@newbridge.com










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RFC 2495                   DS1/E1/DS2/E2 MIB                January 1999


11.  Full Copyright Statement

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

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works.  However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assigns.

   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
























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