The NSP module implements one of the protocols in the Transport
    layer described by the Digital Network Architecture.

    NSP performs the following functions:

    -  Enables the creation and destruction of transport connections
       used for sending messages within a network node and between
       network nodes.

    -  Manages the movement of expedited and normal data from transmit
       buffers to receive buffers, using flow control mechanisms.

    -  Breaks up normal data messages into segments that can be
       transmitted individually, and reassembles these segments into
       correct order after they have been received.

    -  Guarantees the delivery of data and control messages to a
       specified destination using an error correction mechanism.