RFC 146 (rfc146) - Page 2 of 6

Views on issues relevant to data sharing on computer networks

Our Views

    One approach to achieving data sharing on the ARPA Network can
be thought of as having three stages, which roughly correspond to
the modes of use or operation. Within each stage are various levels
of development required to get to the next stage. This development
is not necessarily sequential. A description of the three stages
follows.

Stage 1: Data handling services are provided at various Hosts.
         The user talks directly to the serving Host (via TELNET
         or by addressing a known socket) to explicitly access
         the service.  This mode of operation corresponds to
         Bhushan's category of "direct" usage (RFC #114).  The
         data services provided by the serving Host range from
         simple ones, such as White's file transfer system (RFC #122)
         to sophisticated systems such as the CCA's data machine
         (NIC 5791 and 6706).

Stage 2: The user has access to an intermediate process or data
         control facility* that routes his requests for a particular
         data service to the serving system. The user must explicitly
         identify the data services to the used.  This mode of
         operation corresponds to Bhushan's category of "indirect"
         access. The data control facility provides the necessary
         control commands, data transformations, and accessing
         methods. A single request would include the use of several
         interacting services. For example, Heafner's Data
         Reconfiguration Service (RFC #l38) could be used in
         conjunction with the use of CCA's data machine.






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*The data control facility is not necessarily located at his local
Host. Such a facility may exist on from one to all Host (i.e.,
ranging from centralized to completely distributed).