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TFTP Blocksize Option (RFC1783)

IP.com Disclosure Number: IPCOM000004036D
Original Publication Date: 1995-Mar-01
Included in the Prior Art Database: 2000-Sep-13
Document File: 4 page(s) / 7K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

G. Malkin: AUTHOR [+2]

Abstract

The Trivial File Transfer Protocol [1] is a simple, lock-step, file transfer protocol which allows a client to get or put a file onto a remote host. One of its primary uses is the booting of diskless nodes on a Local Area Network. TFTP is used because it is very simple to implement in a small node's limited ROM space. However, the choice of a 512-byte blocksize is not the most efficient for use on a LAN whose MTU may 1500 bytes or greater.

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Network Working Group G. Malkin

Request for Comments: 1783 Xylogics, Inc.

Updates: 1350 A. Harkin

Category: Standards Track Hewlett Packard Co.

March 1995

TFTP Blocksize Option

Status of this Memo

This document specifies an Internet standards track protocol for the

Internet community, and requests discussion and suggestions for

improvements. Please refer to the current edition of the "Internet

Official Protocol Standards" (STD 1) for the standardization state

and status of this protocol. Distribution of this memo is unlimited.

Abstract

The Trivial File Transfer Protocol [1] is a simple, lock-step, file

transfer protocol which allows a client to get or put a file onto a

remote host. One of its primary uses is the booting of diskless

nodes on a Local Area Network. TFTP is used because it is very

simple to implement in a small node's limited ROM space. However,

the choice of a 512-byte blocksize is not the most efficient for use

on a LAN whose MTU may 1500 bytes or greater.

This document describes a TFTP option which allows the client and

server to negotiate a blocksize more applicable to the network

medium. The TFTP Option Extension mechanism is described in [2].

Blocksize Option Specification

The TFTP Read Request or Write Request packet is modified to include

the blocksize option as follows:

+-------+---~~---+---+---~~---+---+---~~---+---+---~~---+---+

| opc |filename| 0 | mode | 0 | blksize| 0 | #octets| 0 |

+-------+---~~---+---+---~~---+---+---~~---+---+---~~---+---+

opc

The opcode field contains either a 1, for Read Requests, or 2,

for Write Requests, as defined in [1].

filename

The name of the file to be read or written, as defined in [1].

This is a NULL-terminated field.

mode

The mode of the file transfer: "netascii", "octet", or "mail",

as defined in [1]. This is a NULL-terminated field.

blksize

The Blocksize option, "blksize" (case insensitive). This is a

NULL-terminated field.

#octets

The number of octets in a block, specified in ASCII. Valid

values range between "8" and "65464" octets, inclusive. This

is a NULL-terminated field.

For example:

+-------+--------+---+--------+---+--------+---+--------+---+

| 1 | foobar | 0 | binary | 0 | blksize| 0 | 1432 | 0 |

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