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TFTP Blocksize Option (RFC2348)

IP.com Disclosure Number: IPCOM000002917D
Original Publication Date: 1998-May-01
Included in the Prior Art Database: 2019-Feb-15
Document File: 5 page(s) / 7K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

G. Malkin: AUTHOR [+1]

Related Documents

10.17487/RFC2348: DOI

Abstract

The Trivial File Transfer Protocol is a simple, lock-step, file transfer protocol which allows a client to get or put a file onto a remote host. This document describes a TFTP option which allows the client and server to negotiate a blocksize more applicable to the network medium. [STANDARDS-TRACK]

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 38% of the total text.

Network Working Group G. Malkin Request for Commments: 2348 Bay Networks Updates: 1350 A. Harkin Obsoletes: 1783 Hewlett Packard Co. Category: Standards Track May 1998

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.

Copyright Notice

Copyright (C) The Internet Society (1998). All Rights Reserved.

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-octet blocksize is not the most efficient for use on a LAN whose MTU may 1500 octets 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. Note that all fields except "opc" are NULL-terminated.

+-------+---˜˜---+---+---˜˜---+---+---˜˜---+---+---˜˜---+---+ | 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].

Malkin & Harkin Standards Track [Page 1]

RFC 2348 TFTP Blocksize Option May 1998

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

mode The mode of the file transfer: "netascii", "octet", or "mail", as defined in [1].

blksize The Blocksize option, "blksize" (case in-sensitive).

#octets The number of octets in a block, specified in ASCII. Valid values range between "8" and "65464" octets, inclusive. The blocksize refers to the number of data octets; it does not include the four octets of TFTP header.

For example:

+-------+--------+---+--------+---+--------+---+--------+---+ | 1 | foobar | 0 | octet | 0 | blksize| 0 | 1428 | 0 | +-------+--------+---+--------+---+--------+---+--------+---+

is a Read Request, for the file named "foobar", in octet (binary) transfer mode, with a block size of 1428 octets (Ethernet MTU, less the TFTP, UDP and IP header lengths).

If the server is willing to accept the blocksize option, it sends an Option Acknowledgment (OACK) to the client. The specified value must be less than or equal to the value specified by the client. The client must then either use the size specified in the OACK, or send an ERROR packet, with error code 8, to terminate the transfer.

The rules for determ...

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