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rfc:rfc2495

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

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

Status of this Memo

 This document specifies an Internet standards track protocol for the
 Internet community, and requests discussion and suggestions for
 improvements.  Please refer to the current edition of the "Internet
 Official Protocol Standards" (STD 1) for the standardization state
 and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

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

Abstract

 This memo defines a portion of the Management Information Base (MIB)
 for use with network management protocols in the Internet community.
 In particular, it describes objects used for managing DS1, E1, DS2
 and E2 interfaces.  This document is a companion document with
 Definitions of Managed Objects for the DS0 (RFC 2494 [30]), DS3/E3
 (RFC 2496 [28]), and the work in progress, SONET/SDH Interface Types.
 This memo specifies a MIB module in a manner that is both compliant
 to the SNMPv2 SMI, and semantically identical to the peer SNMPv1
 definitions.

Table of Contents

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

Fowler, Ed. Standards Track [Page 1] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

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

1. The SNMP Management Framework

 The SNMP Management Framework presently consists of five major
 components:
  o   An overall architecture, described in RFC 2271 [1].
  o   Mechanisms for describing and naming objects and events for the
      purpose of management. The first version of this Structure of
      Management Information (SMI) is called SMIv1 and described in
      STD 16, RFC 1155 [2], STD 16, RFC 1212 [3] and RFC 1215 [4]. The
      second version, called SMIv2, is described in RFC 1902 [5], RFC
      1903 [6] and RFC 1904 [7].
  o   Message protocols for transferring management information. The
      first version of the SNMP message protocol is called SNMPv1 and
      described in STD 15, RFC 1157 [8]. A second version of the SNMP
      message protocol, which is not an Internet standards track
      protocol, is called SNMPv2c and described in RFC 1901 [9] and
      RFC 1906 [10].  The third version of the message protocol is

Fowler, Ed. Standards Track [Page 2] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

      called SNMPv3 and described in RFC 1906 [10], RFC 2272 [11] and
      RFC 2274 [12].
  o   Protocol operations for accessing management information. The
      first set of protocol operations and associated PDU formats is
      described in STD 15, RFC 1157 [8]. A second set of protocol
      operations and associated PDU formats is described in RFC 1905
      [13].
  o   A set of fundamental applications described in RFC 2273 [14] and
      the view-based access control mechanism described in RFC 2275
      [15].  Managed objects are accessed via a virtual information
      store, termed the Management Information Base or MIB.  Objects
      in the MIB are defined using the mechanisms defined in the SMI.
      This memo specifies a MIB module that is compliant to the SMIv2.
      A MIB conforming to the SMIv1 can be produced through the
      appropriate translations. The resulting translated MIB must be
      semantically equivalent, except where objects or events are
      omitted because no translation is possible (use of Counter64).
      Some machine readable information in SMIv2 will be converted
      into textual descriptions in SMIv1 during the translation
      process. However, this loss of machine readable information is
      not considered to change the semantics of the MIB.

1.1. Changes from RFC1406

 The changes from RFC1406 are the following:
      (1)  The Fractional Table has been deprecated.
      (2)  This document uses SMIv2.
      (3)  Usage is given for ifTable and ifXTable.
      (4)  Example usage of ifStackTable is included.
      (5)  dsx1IfIndex has been deprecated.
      (6)  Support for DS2 and E2 have been added.
      (7)  Additional lineTypes for DS2, E2, and unframed E1
           were added.
      (8)  The definition of valid intervals has been clarified
           for the case where the agent proxied for other devices.  In
           particular, the treatment of missing intervals has been
           clarified.

Fowler, Ed. Standards Track [Page 3] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

      (9)  An inward loopback has been added.
      (10) Additional lineStatus bits have been added for Near End in
           Unavailable Signal State, Carrier Equipment Out of Service,
           DS2 Payload AIS, and DS2 Performance Threshold.
      (11) A read-write line Length object has been added.
      (12) Signal mode of other has been added.
      (13) Added a lineStatus last change, trap and enabler.
      (14) The e1(19) ifType has been obsoleted so this MIB
           does not list it as a supported ifType.
      (15) Textual Conventions for statistics objects have been used.
      (16) A new object, dsx1LoopbackStatus has been introduced to
           reflect the loopbacks established on a DS1 interface and
           the source to the requests.  dsx1LoopbackConfig continues
           to be the desired loopback state while dsx1LoopbackStatus
           reflects the actual state.
      (17) A dual loopback has been added to allow the setting of an
           inward loopback and a line loopback at the same time.
      (18) An object indicating which channel to use within a parent
           object (i.e. DS3) has been added.
      (19) An object has been added to indicate whether or not this
           DS1/E1 is channelized.
      (20) Line coding type of B6ZS has been added for DS2

2. Overview

 These objects are used when the particular media being used to
 realize an interface is a DS1/E1/DS2/E2 interface.  At present, this
 applies to these values of the ifType variable in the Internet-
 standard MIB:
      ds1 (18)
 The definitions contained herein are based on the AT&T T-1 Superframe
 (a.k.a., D4) and Extended Superframe (ESF) formats [17, 18], the
 latter of which conforms to ANSI specifications [19], and the CCITT
 Recommendations [20, 21], referred to as E1 for the rest of this
 memo.

Fowler, Ed. Standards Track [Page 4] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

 The various DS1 and E1 line disciplines are similar enough that
 separate MIBs are unwarranted, although there are some differences.
 For example, Loss of Frame is defined more rigorously in the ESF
 specification than in the D4 specification, but it is defined in
 both.  Therefore,  interface types e1(19) and g703at2mb(67) have been
 obsoleted.
 Where it is necessary to distinguish between the flavors of E1 with
 and without CRC, E1-CRC denotes the "with CRC" form (G.704 Table 4b)
 and E1-noCRC denotes the "without CRC" form (G.704 Table 4a).

2.1. Use of ifTable for DS1 Layer

 Only the ifGeneralGroup needs to be supported.
         ifTable Object    Use for DS1 Layer
         ifIndex           Interface index.
         ifDescr           See interfaces MIB [16]
         ifType            ds1(18)
         ifSpeed           Speed of line rate
                           DS1 - 1544000
                           E1  - 2048000
                           DS2 - 6312000
                           E2  - 8448000
         ifPhysAddress     The value of the Circuit Identifier.
                           If no Circuit Identifier has been assigned
                           this object should have an octet string
                           with zero length.
         ifAdminStatus     See interfaces MIB [16]
         ifOperStatus      See interfaces MIB [16]
         ifLastChange      See interfaces MIB [16]
         ifName            See interfaces MIB [16].
         ifLinkUpDownTrapEnable   Set to enabled(1).
         ifHighSpeed       Speed of line in Mega-bits per second
                           (2, 6, or 8)
         ifConnectorPresent Set to true(1) normally, except for

Fowler, Ed. Standards Track [Page 5] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

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

2.2. Usage Guidelines

2.2.1. Usage of ifStackTable for Routers and DSUs

 The object dsx1IfIndex has been deprecated.  This object previously
 allowed a very special proxy situation to exist for Routers and CSUs.
 This section now describes how to use ifStackTable to represent this
 relationship.
 The paragraphs discussing dsx1IfIndex and dsx1LineIndex have been
 preserved in Appendix A for informational purposes.
 The ifStackTable is used in the proxy case to represent the
 association between pairs of interfaces, e.g. this T1 is attached to
 that T1.  This use is consistent with the use of the ifStackTable to
 show the association between various sub-layers of an interface.  In
 both cases entire PDUs are exchanged between the interface pairs - in
 the case of a T1, entire T1 frames are exchanged; in the case of PPP
 and HDLC, entire HDLC frames are exchanged.  This usage is not meant
 to suggest the use of the ifStackTable to represent Time Division
 Multiplexing (TDM) connections in general.
 External&Internal interface scenario: the SNMP Agent resides on a
 host external from the device supporting DS1 interfaces (e.g., a
 router). The Agent represents both the host and the DS1 device.
 Example:
 A shelf full of CSUs connected to a Router. An SNMP Agent residing on
 the router proxies for itself and the CSU. The router has also an
 Ethernet interface:

Fowler, Ed. Standards Track [Page 6] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

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

Fowler, Ed. Standards Track [Page 7] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

 If the CSU shelf is managed by itself by a local SNMP Agent, the
 situation would be identical, except the Ethernet and the 4 router
 interfaces are deleted.  Interfaces would also be numbered from 1 to
 8.
         ifIndex  Description
         1        Line#A CSU Router
         2        Line#B CSU Router
         3        Line#C CSU Router
         4        Line#D CSU Router
         5        Line#A CSU Network
         6        Line#B CSU Network
         7        Line#C CSU Network
         8        Line#D CSU Network
         ifStackTable Entries
         HigherLayer   LowerLayer
         1             5
         2             6
         3             7
         4             8

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

 An example is given of how DS1/E2 interfaces are stacked on DS2/E2
 interfaces.  It is not necessary nor is it always desirable to
 represent DS2 interfaces.  If this is required, the following
 stacking should be used.  All ifTypes are ds1.  The DS2 is determined
 by examining ifSpeed or dsx1LineType.
      ifIndex  Description
      1        DS1 #1
      2        DS1 #2
      3        DS1 #3
      4        DS1 #4
      5        DS2
      ifStackTable Entries
      HigherLayer   LowerLayer
      1             5
      2             5
      3             5
      4             5

Fowler, Ed. Standards Track [Page 8] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

2.2.3. Usage of Channelization for DS3, DS1, DS0

 An example is given here to explain the channelization objects in the
 DS3, DS1, and DS0 MIBs to help the implementor use the objects
 correctly. Treatment of E3 and E1 would be similar, with the number
 of DS0s being different depending on the framing of the E1.
 Assume that a DS3 (with ifIndex 1) is Channelized into DS1s (without
 DS2s).  The object dsx3Channelization is set to enabledDs1.  There
 will be 28 DS1s in the ifTable.  Assume the entries in the ifTable
 for the DS1s are created in channel order and the ifIndex values are
 2 through 29. In the DS1 MIB, there will be an entry in the
 dsx1ChanMappingTable for each ds1.  The entries will be as follows:
         dsx1ChanMappingTable Entries
         ifIndex  dsx1Ds1ChannelNumber   dsx1ChanMappedIfIndex
         1        1                      2
         1        2                      3
         ......
         1        28                     29
 In addition, the DS1s are channelized into DS0s.  The object
 dsx1Channelization is set to enabledDS0 for each DS1.   When this
 object is set to this value, 24 DS0s are created by the agent. There
 will be 24 DS0s in the ifTable for each DS1.  If the
 dsx1Channelization is set to disabled, the 24 DS0s are destroyed.
 Assume the entries in the ifTable are created in channel order and
 the ifIndex values for the DS0s in the first DS1 are 30 through 53.
 In the DS0 MIB, there will be an entry in the dsx0ChanMappingTable
 for each DS0.  The entries will be as follows:
         dsx0ChanMappingTable Entries
         ifIndex   dsx0Ds0ChannelNumber  dsx0ChanMappedIfIndex
         2         1                     30
         2         2                     31
         ......
         2         24                    53

2.2.4. Usage of Channelization for DS3, DS2, DS1

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

Fowler, Ed. Standards Track [Page 9] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

 Assume that a DS3 (with ifIndex 1) is Channelized into DS2s.  The
 object dsx3Channelization is set to enabledDs2.  There will be 7 DS2s
 (ifType of DS1) in the ifTable.  Assume the entries in the ifTable
 for the DS2s are created in channel order and the ifIndex values are
 2 through 8. In the DS1 MIB, there will be an entry in the
 dsx1ChanMappingTable for each DS2.  The entries will be as follows:
         dsx1ChanMappingTable Entries
         ifIndex  dsx1Ds1ChannelNumber   dsx1ChanMappedIfIndex
         1        1                      2
         1        2                      3
         ......
         1        7                      8
 In addition, the DS2s are channelized into DS1s.  The object
 dsx1Channelization is set to enabledDS1 for each DS2.  There will be
 4 DS1s in the ifTable for each DS2.  Assume the entries in the
 ifTable are created in channel order and the ifIndex values for the
 DS1s in the first DS2 are 9 through 12, then 13 through 16 for the
 second DS2, and so on.  In the DS1 MIB, there will be an entry in the
 dsx1ChanMappingTable for each DS1.  The entries will be as follows:
         dsx1ChanMappingTable Entries
         ifIndex   dsx1Ds1ChannelNumber  dsx1ChanMappedIfIndex
         2         1                     9
         2         2                     10
         2         3                     11
         2         4                     12
         3         1                     13
         3         2                     14
         ...
         8         4                     36

2.2.5. Usage of Loopbacks

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

Fowler, Ed. Standards Track [Page 10] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

 The remote end can also request loopbacks either through the FDL
 channel if ESF or inband if D4.  The loopbacks that can be request
 this way are:
     LineLoopback
     PayloadLoopback (if ESF framing)
     NoLoopback
 To model the current state of loopbacks on a DS1 interface, the
 object dsx1LoopbackStatus defines which loopback is currently applies
 to an interface.  This objects, which is a bitmap, will have bits
 turned on which reflect the currently active loopbacks on the
 interface as well as the source of those loopbacks.
 The following restrictions/rules apply to loopbacks:
 The far end cannot undo loopbacks set by a manager.
 A manager can undo loopbacks set by the far end.
 Both a line loopback and an inward loopback can be set at the same
 time.  Only these two loopbacks can co-exist and either one may be
 set by the manager or the far end.  A LineLoopback request from the
 far end is incremental to an existing Inward loopback established by
 a manager.  When a NoLoopback is received from the far end in this
 case, the InwardLoopback remains in place.

2.3. Objectives of this MIB Module

 There are numerous things that could be included in a MIB for DS1
 signals:  the management of multiplexors, CSUs, DSUs, and the like.
 The intent of this document is to facilitate the common management of
 all devices with DS1, E1, DS2, or E3 interfaces.  As such, a design
 decision was made up front to very closely align the MIB with the set
 of objects that can generally be read from these types devices that
 are currently deployed.
 J2 interfaces are not supported by this MIB.

2.4. DS1 Terminology

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

Fowler, Ed. Standards Track [Page 11] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

2.4.1. Error Events

 Bipolar Violation (BPV) Error Event
     A BPV error event for an AMI-coded signal is the occurrence of a
     pulse of the same polarity as the previous pulse.  (See T1.231
     Section 6.1.1.1.1) A BPV error event for a B8ZS- or HDB3- coded
     signal is the occurrence of a pulse of the same polarity as the
     previous pulse without being a part of the zero substitution
     code.
 Excessive Zeroes (EXZ) Error Event
     An Excessive Zeroes error event for an AMI-coded signal is the
     occurrence of more than fifteen contiguous zeroes.  (See T1.231
     Section 6.1.1.1.2) For a B8ZS coded signal, the defect occurs
     when more than seven contiguous zeroes are detected.
 Line Coding Violation (LCV) Error Event
     A Line Coding Violation (LCV) is the occurrence of either a
     Bipolar Violation (BPV) or Excessive Zeroes (EXZ) Error Event.
     (Also known as CV-L; See T1.231 Section 6.5.1.1)
 Path Coding Violation (PCV) Error Event
     A Path Coding Violation error event is a frame synchronization
     bit error in the D4 and E1-noCRC formats, or a CRC or frame
     synch. bit error in the ESF and E1-CRC formats. (Also known as
     CV-P; See T1.231 Section 6.5.2.1)
 Controlled Slip (CS) Error Event
     A Controlled Slip is the replication or deletion of the payload
     bits of a DS1 frame.  (See T1.231 Section 6.1.1.2.3) A Controlled
     Slip may be performed when there is a difference between the
     timing of a synchronous receiving terminal and the received
     signal.  A Controlled Slip does not cause an Out of Frame defect.

2.4.2. Performance Defects

 Out Of Frame (OOF) Defect
     An OOF defect is the occurrence of a particular density of
     Framing Error events. (See T1.231 Section 6.1.2.2.1)
     For DS1 links, an Out of Frame defect is declared when the
     receiver detects two or more framing errors within a 3 msec
     period for ESF signals and 0.75 msec for D4 signals, or two or
     more errors out of five or fewer consecutive framing-bits.
     For E1 links, an Out Of Frame defect is declared when three
     consecutive frame alignment signals have been received with an
     error (see G.706 Section 4.1 [26]).

Fowler, Ed. Standards Track [Page 12] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

     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).

Fowler, Ed. Standards Track [Page 13] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

2.4.3. Performance Parameters

 All performance parameters are accumulated in fifteen minute
 intervals and up to 96 intervals (24 hours worth) are kept by an
 agent.  Fewer than 96 intervals of data whelfill be available if the
 agent has been restarted within the last 24 hours.  In addition,
 there is a rolling 24-hour total of each performance parameter.
 Performance parameters continue to be collected when the interface is
 down.
 There is no requirement for an agent to ensure fixed relationship
 between the start of a fifteen minute interval and any wall clock;
 however some agents may align the fifteen minute intervals with
 quarter hours.
 Performance parameters are of types PerfCurrentCount,
 PerfIntervalCount and PerfTotalCount.  These textual conventions are
 all Gauge32, and they are used because it is possible for these
 objects to decrease.  Objects may decrease when Unavailable Seconds
 occurs across a fifteen minutes interval boundary. See Unavailable
 Seconds discussion later in this section.
  Line Errored Seconds (LES)
      A Line Errored Second is a second in which one or more Line Code
      Violation error events were detected. (Also known as ES-L; See
      T1.231 Section 6.5.1.2)
  Controlled Slip Seconds (CSS)
      A Controlled Slip Second is a one-second interval containing one
      or more controlled slips.  (See T1.231 Section 6.5.2.8) This is
      not incremented during an Unavailable Second.
  Errored Seconds (ES)
      For ESF and E1-CRC links an Errored Second is a second with one
      or more Path Code Violation OR one or more Out of Frame defects
      OR one or more Controlled Slip events OR a detected AIS defect.
      (See T1.231 Section 6.5.2.2 and G.826 [32] Section B.1)
      For D4 and E1-noCRC links, the presence of Bipolar Violations
      also triggers an Errored Second.
      This is not incremented during an Unavailable Second.

Fowler, Ed. Standards Track [Page 14] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

  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.

Fowler, Ed. Standards Track [Page 15] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

  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.

Fowler, Ed. Standards Track [Page 16] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

      In any case, a linkDown trap shall be sent only after the agent
      has determined for certain that the unavailable state has been
      entered, but the time on the trap will be that of the first UAS
      (i.e., 10 seconds earlier).  A linkUp trap shall be handled
      similarly.
      According to ANSI T1.231 unavailable time begins at the _onset_
      of 10 contiguous severely errored seconds -- that is,
      unavailable time starts with the _first_ of the 10 contiguous
      SESs.  Also, while an interface is deemed unavailable all
      counters for that interface are frozen except for the UAS count.
      It follows that an implementation which strictly complies with
      this standard must _not_ increment any counters other than the
      UAS count -- even temporarily -- as a result of anything that
      happens during those 10 seconds.  Since changes in the signal
      state lag the data to which they apply by 10 seconds, an ANSI-
      compliant implementation must pass the the one-second statistics
      through a 10-second delay line prior to updating any counters.
      That can be done by performing the following steps at the end of
      each one second interval.
 i)   Read near/far end CV counter and alarm status flags from the
      hardware.
 ii)  Accumulate the CV counts for the preceding second and compare
      them to the ES and SES threshold for the layer in question.
      Update the signal state and shift the one-second CV counts and
      ES/SES flags into the 10-element delay line.  Note that far-end
      one-second statistics are to be flagged as "absent" during any
      second in which there is an incoming defect at the layer in
      question or at any lower layer.
 iii) Update the current interval statistics using the signal state
      from the _previous_ update cycle and the one-second CV counts
      and ES/SES flags shifted out of the 10-element delay line.
 This approach is further described in Appendix B.

2.4.4. Failure States

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

Fowler, Ed. Standards Track [Page 17] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

  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)

Fowler, Ed. Standards Track [Page 18] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

      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.

Fowler, Ed. Standards Track [Page 19] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

  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."

Fowler, Ed. Standards Track [Page 20] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

2.4.5. Other Terms

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

3. Object Definitions

   DS1-MIB DEFINITIONS ::= BEGIN
   IMPORTS
        MODULE-IDENTITY, OBJECT-TYPE,
        NOTIFICATION-TYPE, transmission         FROM SNMPv2-SMI
        DisplayString, TimeStamp, TruthValue    FROM SNMPv2-TC
        MODULE-COMPLIANCE, OBJECT-GROUP,
        NOTIFICATION-GROUP                      FROM SNMPv2-CONF
        InterfaceIndex, ifIndex                 FROM IF-MIB
        PerfCurrentCount, PerfIntervalCount,
        PerfTotalCount                          FROM PerfHist-TC-MIB;
   ds1 MODULE-IDENTITY
       LAST-UPDATED "9808011830Z"
       ORGANIZATION "IETF Trunk MIB Working Group"
       CONTACT-INFO
         "        David Fowler
          Postal: Newbridge Networks Corporation
                  600 March Road
                  Kanata, Ontario, Canada K2K 2E6
                  Tel: +1 613 591 3600

Fowler, Ed. Standards Track [Page 21] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

                  Fax: +1 613 599 3667
          E-mail: davef@newbridge.com"
       DESCRIPTION
            "The MIB module to describe DS1, E1, DS2, and
             E2 interfaces objects."
       ::= { transmission 18 }
  1. - note that this subsumes cept (19) and g703at2mb (67)
  2. - there is no separate CEPT or G703AT2MB MIB
  1. - The DS1 Near End Group
  1. - The DS1 Near End Group consists of five tables:
  2. - DS1 Configuration
  3. - DS1 Current
  4. - DS1 Interval
  5. - DS1 Total
  6. - DS1 Channel Table
  1. - 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,

Fowler, Ed. Standards Track [Page 22] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

            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 }

Fowler, Ed. Standards Track [Page 23] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

   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

Fowler, Ed. Standards Track [Page 24] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

               "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

Fowler, Ed. Standards Track [Page 25] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

               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

Fowler, Ed. Standards Track [Page 26] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

               "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),

Fowler, Ed. Standards Track [Page 27] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

                    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

Fowler, Ed. Standards Track [Page 28] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

               "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

Fowler, Ed. Standards Track [Page 29] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

          "'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),

Fowler, Ed. Standards Track [Page 30] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

          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

Fowler, Ed. Standards Track [Page 31] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

               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

Fowler, Ed. Standards Track [Page 32] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

               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 }
  1. - 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,

Fowler, Ed. Standards Track [Page 33] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

            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 }

Fowler, Ed. Standards Track [Page 34] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

   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 }

Fowler, Ed. Standards Track [Page 35] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

   dsx1CurrentLCVs OBJECT-TYPE
        SYNTAX PerfCurrentCount
        MAX-ACCESS read-only
        STATUS current
        DESCRIPTION
               "The number of Line Code Violations (LCVs)."
        ::= { dsx1CurrentEntry 11 }
  1. - 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,

Fowler, Ed. Standards Track [Page 36] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

            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."

Fowler, Ed. Standards Track [Page 37] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

        ::= { 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

Fowler, Ed. Standards Track [Page 38] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

        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 }
  1. - 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,

Fowler, Ed. Standards Track [Page 39] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

            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

Fowler, Ed. Standards Track [Page 40] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

               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

Fowler, Ed. Standards Track [Page 41] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

        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 }
  1. - 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

Fowler, Ed. Standards Track [Page 42] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

        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 }
  1. - The DS1 Far End Current Table
   dsx1FarEndCurrentTable OBJECT-TYPE
        SYNTAX  SEQUENCE OF Dsx1FarEndCurrentEntry
        MAX-ACCESS  not-accessible

Fowler, Ed. Standards Track [Page 43] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

        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 }

Fowler, Ed. Standards Track [Page 44] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

   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

Fowler, Ed. Standards Track [Page 45] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

               "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

Fowler, Ed. Standards Track [Page 46] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

        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 }
  1. - 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,

Fowler, Ed. Standards Track [Page 47] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

            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."

Fowler, Ed. Standards Track [Page 48] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

        ::= { 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

Fowler, Ed. Standards Track [Page 49] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

        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 }
  1. - 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,

Fowler, Ed. Standards Track [Page 50] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

            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

Fowler, Ed. Standards Track [Page 51] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

               "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."

Fowler, Ed. Standards Track [Page 52] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

        ::= { 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 }
  1. - 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,

Fowler, Ed. Standards Track [Page 53] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

               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 }

Fowler, Ed. Standards Track [Page 54] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

   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 }
  1. - Ds1 TRAPS
   ds1Traps OBJECT IDENTIFIER ::= { ds1 15 }

Fowler, Ed. Standards Track [Page 55] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

   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 }
  1. - conformance information

ds1Conformance OBJECT IDENTIFIER ::= { ds1 14 }

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

Fowler, Ed. Standards Track [Page 56] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

           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

Fowler, Ed. Standards Track [Page 57] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

               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

Fowler, Ed. Standards Track [Page 58] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

               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

Fowler, Ed. Standards Track [Page 59] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

               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

Fowler, Ed. Standards Track [Page 60] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

                    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 }
  1. - 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

Fowler, Ed. Standards Track [Page 61] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

               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,

Fowler, Ed. Standards Track [Page 62] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

                 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."

Fowler, Ed. Standards Track [Page 63] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

       ::= { 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

Fowler, Ed. Standards Track [Page 64] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

       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

Fowler, Ed. Standards Track [Page 65] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

4. Appendix A - Use of dsx1IfIndex and dsx1LineIndex

 This Appendix exists to document the previous use if dsx1IfIndex and
 dsx1LineIndex and to clarify the relationship of dsx1LineIndex as
 defined in rfc1406 with the dsx1LineIndex as defined in this
 document.
 The following shows the old and new definitions and the relationship:
 [New Definition]: "This object should be made equal to ifIndex.  The
 next paragraph describes its previous usage.  Making the object equal
 to ifIndex allows proper use of ifStackTable and ds0/ds0bundle mibs.
 [Old Definition]: "This object is the identifier of a DS1 Interface
 on a managed device.  If there is an ifEntry that is directly
 associated with this and only this DS1 interface, it should have the
 same value as ifIndex.  Otherwise, number the dsx1LineIndices with an
 unique identifier following the rules of choosing a number that is
 greater than ifNumber and numbering the inside interfaces (e.g.,
 equipment side) with even numbers and outside interfaces (e.g,
 network side) with odd numbers."
 When the "Old Definition" was created, it was described this way to
 allow a manager to treat the value _as if_ it were and ifIndex, i.e.
 the value would either be:  1) an ifIndex value or 2) a value that
 was guaranteed to be different from all valid ifIndex values.
 The new definition is a subset of that definition, i.e. the value is
 always an ifIndex value.
 The following is Section 3.1 from rfc1406:
 Different physical configurations for the support of SNMP with DS1
 equipment exist. To accommodate these scenarios, two different
 indices for DS1 interfaces are introduced in this MIB.  These indices
 are dsx1IfIndex and dsx1LineIndex.
 External interface scenario: the SNMP Agent represents all managed
 DS1 lines as external interfaces (for example, an Agent residing on
 the device supporting DS1 interfaces directly):
 For this scenario, all interfaces are assigned an integer value equal
 to ifIndex, and the following applies:
    ifIndex=dsx1IfIndex=dsx1LineIndex for all interfaces.

Fowler, Ed. Standards Track [Page 66] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

 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

Fowler, Ed. Standards Track [Page 67] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

                 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

Fowler, Ed. Standards Track [Page 68] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

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

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

+———————————————————————+

READ COUNTERS & STATUS INFO FROM HARDWARE
BPV EXZ LOS FE CRC CS AIS SEF OOF LOF RAI G1-G6 SE FE LV SL

+———————————————————————+

 |   |   |   |  |   |  |   |   |   |         |    |    |  |  |  |
 |   |   |   |  |   |  |   |   |   |         |    |    |  |  |  |
 V   V   V   V  V   V  V   V   V   V         V    V    V  V  V  V

+———————————————————————+

ACCUM ONE-SEC STATS, CHK ERR THRESHOLDS, & UPDT SIGNAL STATE
←——— NEAR END ———–> ←——- FAR END ——>
LCV LES PCV ES CSS BES SES SEFS A/U PCV ES CSS BES SES SEFS A/U

+———————————————————————+

  |   |   |  |   |   |   |   |    |      |  |   |   |   |   |    |
  |   |   |  |   |   |   |   |    |      |  |   |   |   |   |    |
  V   V   V  V   V   V   V   V    |      V  V   V   V   V   V    |

+——————————+ | +———————-+ | | ONE-SEC DELAY | | | ONE-SEC DELAY | | | (1 OF 10) | | | (1 OF 10) | | +——————————+ | +———————-+ |

 |   |   |  |   |   |   |   |     |      |  |   |   |   |   |    |
 /   /   /  /   /   /   /   /     /      /  /   /   /   /   /    /
 |   |   |  |   |   |   |   |     |      |  |   |   |   |   |    |
 V   V   V  V   V   V   V   V     |      V  V   V   V   V   V    |

+——————————+ | +———————-+ | | ONE-SEC DELAY | | | ONE-SEC DELAY | | | (10 OF 10) | | | (10 OF 10) | | +——————————+ | +———————-+ |

 |   |   |  |   |   |   |   |     |      |  |   |   |   |   |    |
 V   V   V  V   V   V   V   V     V      V  V   V   V   V   V    V

Fowler, Ed. Standards Track [Page 69] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

+———————————————————————+

UPDATE STATISTICS COUNTERS
←————- NEAR END ———–> ←——– FAR END ———>
LCV LES PCV ES CSS BES SES SEFS UAS DM PCV ES CSS BES SES SEFS UAS DM

+———————————————————————+

 Note that if such a procedure is adopted there is no current interval
 data for the first ten seconds after a system comes up.
 noSuchInstance must be returned if a management station attempts to
 access the current interval counters during this time.
 It is an implementation-specific matter whether an agent assumes that
 the initial state of the interface is available or unavailable.

6. Intellectual Property

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

7. Acknowledgments

 This document was produced by the Trunk MIB Working Group.

Fowler, Ed. Standards Track [Page 70] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

8. References

 [1]  Harrington, D., Presuhn, R. and B. Wijnen, "An Architecture for
      Describing SNMP Management Frameworks", RFC 2271, January 1998.
 [2]  Rose, M. and K. McCloghrie, "Structure and Identification of
      Management Information for TCP/IP-based Internets", STD 16, RFC
      1155, May 1990.
 [3]  Rose, M. and K. McCloghrie, "Concise MIB Definitions", STD 16,
      RFC 1212, March 1991.
 [4]  Rose, M., "A Convention for Defining Traps for use with the
      SNMP", RFC 1215, March 1991.
 [5]  Case, J., McCloghrie, K., Rose, M. and S. Waldbusser, "Structure
      of Management Information for Version 2 of the Simple Network
      Management Protocol (SNMPv2)", RFC 1902, January 1996.
 [6]  Case, J., McCloghrie, K., Rose, M. and S. Waldbusser, "Textual
      Conventions for Version 2 of the Simple Network Management
      Protocol (SNMPv2)", RFC 1903, January 1996.
 [7]  Case, J., McCloghrie, K., Rose, M. and S. Waldbusser,
      "Conformance Statements for Version 2 of the Simple Network
      Management Protocol (SNMPv2)", RFC 1904, January 1996.
 [8]  Case, J., Fedor, M., Schoffstall, M. and J. Davin, "Simple
      Network Management Protocol", STD 15, RFC 1157, May 1990.
 [9]  Case, J., McCloghrie, K., Rose, M. and S. Waldbusser,
      "Introduction to Community-based SNMPv2", RFC 1901, January
      1996.
 [10] Case, J., McCloghrie, K., Rose, M. and S. Waldbusser, "Transport
      Mappings for Version 2 of the Simple Network Management Protocol
      (SNMPv2)", RFC 1906, January 1996.
 [11] Case, J., Harrington D., Presuhn R. and B. Wijnen, "Message
      Processing and Dispatching for the Simple Network Management
      Protocol (SNMP)", RFC 2272, January 1998.
 [12] Blumenthal, U. and B. Wijnen, "User-based Security Model (USM)
      for version 3 of the Simple Network Management Protocol
      (SNMPv3)", RFC 2274, January 1998.

Fowler, Ed. Standards Track [Page 71] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

 [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.

Fowler, Ed. Standards Track [Page 72] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

 [26] CCITT Specifications Volume III, Recommendation G.706, Frame
      Alignment and Cyclic Redundancy Check (CRC) Procedures Relating
      to Basic Frame Structures Defined in Recommendation G.704, July
      1988.
 [27] CCITT Specifications Volume III, Recommendation G.732,
      Characteristics Of Primary PCM Multiplex Equipment Operating at
      2048 kbit/s, July 1988.
 [28] Fowler, D., "Definitions of Managed Objects for the DS3/E3
      Interface Types", RFC 2496, Janaury 1999.
 [29] Brown, T., and Tesink, K., "Definitions of Managed Objects for
      the SONET/SDH Interface Type", Work in Progress.
 [30] Fowler, D., "Definitions of Managed Objects for the Ds0 and
      DS0Bundle Interface Types", RFC 2494, January 1999.
 [31] ITU-T G.775: Loss of signal (LOS) and alarm indication signal
      (AIS) defect detection and clearance criteria, May 1995.
 [32] ITU-T G.826: Error performance parameters and objectives for
      international, constant bit rate digital paths at or above the
      primary rate, November 1993.
 [33] American National Standard for Telecommunications -- Digital
      Hierarchy - Electrical Interfaces, T1.102, December 1993.
 [34] American National Standard for Telecommunications -- Digital
      Hierarchy - Format Specifications, T1.107, August 1988.
 [35] Tesink, K., "Textual Conventions for MIB Modules Using
      Performance History Based on 15 Minute Intervals", RFC XXXX,
      January 1999.

9. Security Considerations

 SNMPv1 by itself is such an insecure environment.  Even if the
 network itself is secure (for example by using IPSec), even then,
 there is no control as to who on the secure network is allowed to
 access and GET (read) the objects in this MIB.
 It is recommended that the implementors consider the security
 features as provided by the SNMPv3 framework.  Specifically, the use
 of the User-based Security Model RFC 2274 [12] and the View-based
 Access Control Model RFC 2275 [15] is recommended.

Fowler, Ed. Standards Track [Page 73] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

 It is then a customer/user responsibility to ensure that the SNMP
 entity giving access to an instance of this MIB, is properly
 configured to give access to those objects only to those principals
 (users) that have legitimate rights to access them.
 Setting any of the following objects to an inappropriate value can
 cause loss of traffic.  The definition of inappropriate varies for
 each object.  In the case of dsx1LineType, for example, both ends of
 a ds1/e1 must have the same value in order for traffic to flow.  In
 the case of dsx1SendCode and dsx1LoopbackConfig, for another example,
 traffic may stop transmitting when particular loopbacks are applied.
    dsx1LineType
    dsx1LineCoding
    dsx1SendCode
    dsx1LoopbackConfig
    dsx1SignalMode
    dsx1TransmitClockSource
    dsx1Fdl
    dsx1LineLength
    dsx1Channelization
 Setting the following object is mischevious, but not harmful to
 traffic.
    dsx1CircuitIdentifier
 Setting the following object can cause an increase in the number of
 traps received by the network management station.
    dsx1LineStatusChangeTrabEnable

10. Author's Address

 David Fowler
 Newbridge Networks
 600 March Road
 Kanata, Ontario, Canada K2K 2E6
 Phone: (613) 599-3600, ext 6559
 EMail: davef@newbridge.com

Fowler, Ed. Standards Track [Page 74] RFC 2495 DS1/E1/DS2/E2 MIB January 1999

11. Full Copyright Statement

 Copyright (C) The Internet Society (1999).  All Rights Reserved.
 This document and translations of it may be copied and furnished to
 others, and derivative works that comment on or otherwise explain it
 or assist in its implementation may be prepared, copied, published
 and distributed, in whole or in part, without restriction of any
 kind, provided that the above copyright notice and this paragraph are
 included on all such copies and derivative works.  However, this
 document itself may not be modified in any way, such as by removing
 the copyright notice or references to the Internet Society or other
 Internet organizations, except as needed for the purpose of
 developing Internet standards in which case the procedures for
 copyrights defined in the Internet Standards process must be
 followed, or as required to translate it into languages other than
 English.
 The limited permissions granted above are perpetual and will not be
 revoked by the Internet Society or its successors or assigns.
 This document and the information contained herein is provided on an
 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
 TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
 BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Fowler, Ed. Standards Track [Page 75]

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