draft-ietf-tftpexts-blksize-opt-01.txt   rfc1783.txt 
draft-ietf-tftpexts-blksize-opt-01.txt G. Malkin / Xylogics, Inc.
TFTP Blocksize Option A. Harkin / Hewlett Packard Co. Network Working Group G. Malkin
October 1994 Request for Comments: 1783 Xylogics, Inc.
Updates: 1350 A. Harkin
Category: Standards Track Hewlett Packard Co.
March 1995
TFTP Blocksize Option 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 Abstract
The Trivial File Transfer Protocol [1] is a simple, lock-step, file 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 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 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 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, 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 the choice of a 512-byte blocksize is not the most efficient for use
on a LAN whose MTU may 1500 bytes or greater. on a LAN whose MTU may 1500 bytes or greater.
This document describes a TFTP option which allows the client and This document describes a TFTP option which allows the client and
server to negotiate a blocksize more applicable to the network server to negotiate a blocksize more applicable to the network
medium. The TFTP Option Extension mechanism is described in [2]. medium. The TFTP Option Extension mechanism is described in [2].
Status of this Memo
This document is an Internet-Draft. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its areas,
and its working groups. Note that other groups may also distribute
working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
To learn the current status of any Internet-Draft, please check the
"1id-abstracts.txt" listing contained in the Internet-Drafts Shadow
Directories on ds.internic.net (US East Coast), nic.nordu.net
(Europe), ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific
Rim).
Blocksize Option Specification Blocksize Option Specification
The TFTP Read Request or Write Request packet is modified to include The TFTP Read Request or Write Request packet is modified to include
the blocksize option as follows: the blocksize option as follows:
+-------+---~~---+---+---~~---+---+---~~---+---+---~~---+---+ +-------+---~~---+---+---~~---+---+---~~---+---+---~~---+---+
| opc |filename| 0 | mode | 0 | blksize| 0 | #octets| 0 | | opc |filename| 0 | mode | 0 | blksize| 0 | #octets| 0 |
+-------+---~~---+---+---~~---+---+---~~---+---+---~~---+---+ +-------+---~~---+---+---~~---+---+---~~---+---+---~~---+---+
opc opc
skipping to change at page 2, line 22 skipping to change at page 2, line 10
filename filename
The name of the file to be read or written, as defined in [1]. The name of the file to be read or written, as defined in [1].
This is a NULL-terminated field. This is a NULL-terminated field.
mode mode
The mode of the file transfer: "netascii", "octet", or "mail", The mode of the file transfer: "netascii", "octet", or "mail",
as defined in [1]. This is a NULL-terminated field. as defined in [1]. This is a NULL-terminated field.
blksize blksize
The Blocksize option, "blksize" (case in-sensitive). This is a The Blocksize option, "blksize" (case insensitive). This is a
NULL-terminated field. NULL-terminated field.
#octets #octets
The number of octets in a block, specified in ASCII. Valid The number of octets in a block, specified in ASCII. Valid
values range between "8" and "65464" octets, inclusive. This values range between "8" and "65464" octets, inclusive. This
is a NULL-terminated field. is a NULL-terminated field.
For example: For example:
+-------+--------+---+--------+---+--------+---+--------+---+ +-------+--------+---+--------+---+--------+---+--------+---+
skipping to change at page 4, line 33 skipping to change at page 4, line 33
Of course, if the blocksize exceeds the path MTU, IP fragmentation Of course, if the blocksize exceeds the path MTU, IP fragmentation
and reassembly will begin to add more overhead. This will be more and reassembly will begin to add more overhead. This will be more
noticable the greater the number of gateways in the path. noticable the greater the number of gateways in the path.
Security Considerations Security Considerations
Security issues are not discussed in this memo. Security issues are not discussed in this memo.
References References
[1] Sollins, K., "The TFTP Protocol (Revision 2)", Request for [1] Sollins, K., "The TFTP Protocol (Revision 2)", STD 33, RFC 1350,
Comments 1350 (STD 33), October 1992. MIT, July 1992.
[2] Malkin, G., Harkin, A., "TFTP Option Extension", Internet Draft, [2] Malkin, G., and A. Harkin, "TFTP Option Extension", RFC 1782,
draft-malkin-tftp-options-01.txt, September 1994. Xylogics, Inc., Hewlett Packard Co., March 1995.
Authors' Addresses Authors' Addresses
Gary Scott Malkin Gary Scott Malkin
Xylogics, Inc. Xylogics, Inc.
53 Third Avenue 53 Third Avenue
Burlington, MA 01803 Burlington, MA 01803
Phone: (617) 272-8140 Phone: (617) 272-8140
EMail: gmalkin@xylogics.com EMail: gmalkin@xylogics.com
Art Harkin
Internet Services Project
Information Networks Division
19420 Homestead Road MS 43LN
Cupertino, CA 95014
Phone: (408) 447-3755 Art Harkin
EMail: ash@cup.hp.com Internet Services Project
Information Networks Division
19420 Homestead Road MS 43LN
Cupertino, CA 95014
Phone: (408) 447-3755
EMail: ash@cup.hp.com
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