The entity hierarchy for the Frame module is:

    Node___Frame____Link
                  |
                  |_Port

    The FRAME entity is the top-level entity in the hierarchy
    belonging to the Frame module. The entity provides framing
    functions for a communications link. The entity does not provide
    any data link protocol capabilities, and is used by those who
    want or need to operate their own level 2 protocols.

    A FRAME LINK entity is associated with a physical line, and
    controls the framing protocol used on that line. There is one
    frame link entity for each physical line.

    A FRAME PORT entity represents an access point to the data
    link service offered by the Frame module. Ports are created and
    deleted automatically when a client of DDCMP uses the link.