This MIB module describes IDSL (ISDN Digital Line Subscriber)
line interfaces.  The structure of this module resembles that
of the ADSL-LINE-MIB (RFC-2662).  Observe that the tables in
this module do not necessarily extend the tables defined by the
ADSL-LINE-MIB.  Currently, only those tables that contain
configuration information extend the profile tables defined by
the ADSL-LINE-MIB.  This allows the management client to define
xDSL configuration profiles that apply across all xDSL modems,
independent of the technology being utilized by the modem.

*** ABBREVIATIONS, ACRONYMS, AND SYMBOLS ***

ADSL - Asymmetric Digital Subscriber Line.

ATM - Asynchronous Transfer Mode.

BRITE - Basic Rate Interface Terminal Extender.

CV - Coding Violation.

DLC - Data Link Connection.

DSL - Digital Subscriber Line.

ES - Error Second.

IDSL - IDSN Digital Subscriber Loop.

ITU-C - IDSL Transceiver Unit, Central Office end.

ITU-R - IDSL Transceiver Unit, Remote terminal end.

LMI - Link Management Interface.

LOF - Loss Of Frame.

LOS - Loss Of Signal.

NT - Network Terminator.

PPP - Point-to-Point Protocol.

PPPoA - PPP over ATM.

SES - Severely Errored Second.

*** DEFINITIONS ***

CODING VIOLATION
    A coding violation occurs when the incoming signal exhibits
    a CRC anomaly.

DOWNSTREAM
    The flow of data in the direction from the ITU-C to ITU-R.
              
ERRORED SECOND
    A second with one or more coding violations.

LINE RATE
    The total data rate supported by a line.  Observe that the
    payload rate is equal the line rate for the earliest
    implementations of IDSL.  However, the payload rate maybe
    less than the line rate for future implementations.

SEVERELY ERRORED SECOND
    A second with 3 or more coding violations.
                  
UPSTREAM
    The flow of data in the direction from the ATU-R to ATU-C.