RFC 327 (rfc327) - Page 3 of 5
Data and File Transfer workshop notes
Alternative Format: Original Text Document
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