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Coherent File Distribution Protocol (RFC1235)

IP.com Disclosure Number: IPCOM000002050D
Original Publication Date: 1991-Jun-01
Included in the Prior Art Database: 2000-Sep-12
Document File: 10 page(s) / 27K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

J. Ioannidis: AUTHOR [+2]

Abstract

The Coherent File Distribution Protocol (CFDP) has been designed to speed up one-to-many file transfer operations that exhibit traffic coherence on media with broadcast capability. Examples of such coherent file transfers are identical diskless workstations booting simultaneously, software upgrades being distributed to more than one machines at a site, a certain "object" (bitmap, graph, plain text, etc.) that is being discussed in a real-time electronic conference or class being sent to all participants, and so on.

This text was extracted from a ASCII Text document.
This is the abbreviated version, containing approximately 11% of the total text.

Network Working Group J. Ioannidis

Request for Comments: 1235 G. Maguire, Jr.

Columbia University

Department of Computer Science

June 1991

The Coherent File Distribution Protocol

Status of this Memo

This memo describes the Coherent File Distribution Protocol (CFDP).

This is an Experimental Protocol for the Internet community.

Discussion and suggestions for improvement are requested. Please

refer to the current edition of the "IAB Official Protocol Standards"

for the standardization state and status of this protocol.

Distribution of this memo is unlimited.

Introduction

The Coherent File Distribution Protocol (CFDP) has been designed to

speed up one-to-many file transfer operations that exhibit traffic

coherence on media with broadcast capability. Examples of such

coherent file transfers are identical diskless workstations booting

simultaneously, software upgrades being distributed to more than one

machines at a site, a certain "object" (bitmap, graph, plain text,

etc.) that is being discussed in a real-time electronic conference or

class being sent to all participants, and so on.

In all these cases, we have a limited number of servers, usually only

one, and clients (where can be large) that are being sent the

same file. If these files are sent via multiple one-to-one

transfers, the load on both the server and the network is greatly

increased, as the same data are sent times.

We propose a file distribution protocol that takes advantage of the

broadcast nature of the communications medium (e.g., fiber, ethernet,

packet radio) to drastically reduce the time needed for file transfer

and the impact on the file server and the network. While this

protocol was developed to allow the simultaneous booting of diskless

workstations over our experimental packet-radio network, it can be

used in any situation where coherent transfers take place.

CFDP was originally designed as a back-end protocol; a front-end

interface (to convert file names and requests for them to file

handles) is still needed, but a number of existing protocols can be

adapted to use with CFDP. Two such reference applications have been

developed; one is for diskless booting of workstations, a simplified

BOOTP [3] daemon (which we call sbootpd) and a simple, TFTP-like

front end (which we call vtftp). In addition, our CFDP server has

been extended to provide this front-end interface. We do not

consider this front-end part of the CFDP protocol, however, we

present it in this document to provide a complete example.

The two clients and the CFDP server are available as reference

implementations for anonymous ftp from the site CS.COLUMBIA.EDU

(128.59.16.20) in directory pub/...