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Another Look at Data and File Transfer Protocols (RFC0310)

IP.com Disclosure Number: IPCOM000003506D
Original Publication Date: 1972-Apr-03
Included in the Prior Art Database: 2000-Sep-13
Document File: 6 page(s) / 17K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

A.K. Bhushan: AUTHOR

Abstract

Our experience with ad hoc techniques of data and file transfer over the ARPANET together with a better knowledge of terminal IMP (TIP) capabilities and Datacomputer requirements has indicated to us that the Data Transfer Protocol (DTP) (see ref 1) and the File Transfer Protocol (FTP) (see ref 2) could undergo revision. Our effort in implementing DTP and FTP has revealed areas in which the protocols could be simplified without degrading their usefulness.

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Network Working Group A. Bhushan

Request for Comments: 310 MIT-MAC

NIC: 9261 April 3, 1972

Another Look At Data And File Transfer Protocols

Our experience with ad hoc techniques of data and file transfer over

the ARPANET together with a better knowledge of terminal IMP (TIP)

capabilities and Datacomputer requirements has indicated to us that

the Data Transfer Protocol (DTP) (see ref 1) and the File Transfer

Protocol (FTP) (see ref 2) could undergo revision. Our effort in

implementing DTP and FTP has revealed areas in which the protocols

could be simplified without degrading their usefulness.

This paper suggests some specific changes in DTP and FTP that should

make them more useful and/or simplify implementation. The attempt

here is to stimulate thinking so that we may come up with a better

protocol at the forthcoming Data and File Transfer Workshop (see ref

3).

Experience to Date

A number of ad hoc techniques of transmitting data and files across

the ARPANET already exist. Perhaps, the most versatile of these

existing methods is the TENEX "CPYNET" system. The "CPYNET" system

uses an ad hoc or interim file transfer protocol developed by Ray

Tomlinson and others at BBN to transmit files among the TENEX systems

on the ARPANET. [Private Communication with Bill Crowther, BBN.]

In CPYNET, the using process goes through the Initial Connection

Protocol (ICP) to server socket 7, establishing a full-duplex

connection with an 8-bit byte size. Control information, including

user name, password, command (read, write, or append), file name, and

byte size for the data connection is transmitted from the using

process to the serving process. The original full-duplex connection

is then closed, and a new full-duplex connection is established using

the original socket numbers but with possibly a different byte size.

The file is now transmitted on this newly established connection.

The end-of-file is indicated by closing the connection (the mode of

transfer is thus similar to DTP "indefinite bit-stream").

CPYNET has been used quite extensively for transfer of TENEX system

files. Because data is not reformatted, and because the optimum

connection byte size may be used for data transfer, CPYNET is quite

efficient. The PDP-10 (and there are quite a lot in the ARPANET)

works more efficiently with a 36 bit byte size which minimizes

packing and unpacking of data, and increases effective I/O speed

(bit rate is 36 times the I/O word transfer rate in...