RFC 1783 (rfc1783) - Page 1 of 5
TFTP Blocksize Option
Alternative Format: Original Text Document
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.
Malkin & Harkin
