RFC 327 (rfc327) - Page 3 of 5

Data and File Transfer workshop notes

RFC 327          Data and File Transfer Workshop Notes        April 1972


   Abhay Bhushan discussed the evaluation of network protocols and
   presented some preliminary measurement results.  The evaluation
   criteria for protocols should include speed (real time delay and
   transmission rate), efficiency (cpu time or cost), reliability (error
   rate and failure rate), convenience (ease of use and implementation),
   and usage (suitability for various application and user classes).

   The parameters that affect speed and efficiency for given system
   conditions (fixed load, etc.) are:

      1)  Byte size used for NCP connection.

      2)  Average message size used for transmission.

      3)  Data format conversion (e.g., into Network ASCII, DTP Blocks,
          etc.).

      4)  Buffer size and I/O mode used (unit or block mode, etc.).

      5)  Other protocol constraints (acknowledge, error checking,
          connection procedure, etc.).

   There was some discussion as to how data and file transfer protocols
   may be altered to make transfer faster and more efficient by using
   optimum byte size and minimizing some of the constraints that impose
   a large overhead.

   The follow up discussions on DTP and FTP lead to a list of discussion
   and decision items for the next day.  The following is a summary of
   decisions reached on Saturday, April 15, 1972.

      1.  Separate connections are to be used for data and control
          information.

      2.  Control connection is to be a "TELNET" full-duplex connection
          (NVT-ASCII), established via the ICP.  Data connections are to
          be simplex connections established directly.

      3.  The File Transfer and File System commands and their arguments
          shall be printable ASCII strings, instead of numeric codes, so
          that they are directly usable by a user at a terminal.  The
          interaction, however, will be optimized for usage by programs.
          (indirect use).

      4.  The byte size and user socket for data connection, data
          representation, and transfer mode to be used in file transfer
          may be chosen by a user via one or more commands requiring a
          positive or negative acknowledgment.



Bhushan