RFC2495

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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.

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
    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.

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.
    (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

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.

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).

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

Usage Guidelines

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:

     +-----+

| | | | | | +---------------------+ |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

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

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

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

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.

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

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

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.

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.

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.

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.

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]).
   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).

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.
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.
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.
    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.

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.

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)
    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.
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."

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.

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
                Fax: +1 613 599 3667
        E-mail: [email protected]"
     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,
          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 }
 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
             "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
             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
             "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),
                  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
             "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
        "'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),
        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
             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
             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,
          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 }
 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 }
 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,
          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."
      ::= { 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
      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,
          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
             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
      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
      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
      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 }
 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
             "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
      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,
          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."
      ::= { 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
      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,
          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
             "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."
      ::= { 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,
             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 }
 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 }
 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
         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
             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
             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
             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
                  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
             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,
               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."
     ::= { 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
     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

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.

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
               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

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

+---------------------------------------------------------------------+ | 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.

Intellectual Property

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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.

Acknowledgments

This document was produced by the Trunk MIB Working Group.

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.

[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.

[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.

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.

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: [email protected]

11. Full Copyright Statement

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