The entity hierarchy of the LLC2 module is:

    Node___LLC2____Port
                 |
                 |_SAP___Link

    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).

    An LLC2 PORT entity represents an access point to the services
    offered to clients by the LLC2 module.  Each LLC2 PORT entity has
    an LLC2 SAP (service access point) entity associated with it.

    An LLC2 SAP entity allows links to be multiplexed over its
    associated port.

    An LLC2 SAP LINK entity represents one of the links operating over a
    particular sap (service access point).