The LAPB module implements one of the protocols in the Link layer described
    by the Digital Network Architecture.

    You must install the product DEC WAN Device Drivers before you can refer
    to the LAPB Module entities in an NCL command.

    The lapb entity is the top-level entity in the LAPB module hierarchy of
    entities. The LAPB module implements the LAPB link-level protocol which is
    a variation of the HDLC link-level protocol.