The Session layer implements the user interface to the network.
    It is responsible for connection negotiation and establishment.
    The Session Control module performs the following functions:

    o  Manages transport connections on behalf of Session Control
       users.

    o  Enforces access control policies to restrict communication
       between users and between Session Control modules.

    o  Maps from a DNA Naming Service object name to protocols and
       addresses.

    o  Selects from the set of protocols supporting Session Control
       to attempt connection establishment.

    o  Maintains in the namespace the protocol and address
       information corresponding to objects that reside in the same
       node as the local Session Control module.