RFC 2348 (rfc2348) - Page 1 of 5


TFTP Blocksize Option



Alternative Format: Original Text Document



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