The LLC2 module implements one of the protocols in the Data Link layer
    described by the Digital Network Architecture.
    The LLC2 entity is the top-level entity in the LLC2 module hierarchy of
    entities. The LLC2 module controls the operation of the LLC Type 2 data
    link protocol for local area networks LANs.
    The hierarchical relationship of the entities that constitute the LLC2
    module:
                               LLC2
                           Port    Sap
                                    Link