TFTP Timeout Interval and Transfer Size Options (RFC2349)

Network Working Group G. Malkin Request for Commments: 2349 Bay Networks Updates: 1350 A. Harkin Obsoletes: 1784 Hewlett Packard Co. Category: Standards Track May 1998

TFTP Timeout Interval and Transfer Size Options

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.

This document describes two TFTP options. The first allows the client and server to negotiate the Timeout Interval. The second allows the side receiving the file to determine the ultimate size of the transfer before it begins. The TFTP Option Extension mechanism is described in [2].

Timeout Interval Option Specification

The TFTP Read Request or Write Request packet is modified to include the timeout option as follows:

+-------+---˜˜---+---+---˜˜---+---+---˜˜---+---+---˜˜---+---+ | opc |filename| 0 | mode | 0 | timeout| 0 | #secs | 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 2349 TFTP Timeout Interval and Transfer Size Options May 1998

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.

timeout The Timeout Interval option, "timeout" (case in-sensitive). This is a NULL-terminated field.

#secs The number of seconds to wait before retransmitting, specified in ASCII. Valid values range between "1" and "255" seconds, inclusive. This is a NULL-terminated field.

For example:

+-------+--------+---+--------+---+--------+---+-------+---+ | 1 | foobar | 0 | octet | 0 | timeout| 0 | 1 | 0 | +-------+--------+---+--------+---+--------+---+-------+---+

is a Read Request, for the file named "foobar", in octet (binary) transfer mode, with a timeout interval of 1 second.

If the server is willing to accept the timeout option, it sends an Option Acknowledgment (OACK) to the client. The specified timeout value must match the value specified by the client.

Transfer Size Option Specification

The TFTP Read Request or Write Request packet is modified to include the tsize option as follows:

+-------+---˜˜---+---+---˜˜---+---+---˜˜---+---+---˜˜---+---+ | opc |filename| 0 | mode | 0 | tsize | 0 | size | 0 | +-------+---˜˜---+---+---˜˜---+---+---˜˜---+---+---˜˜---+---+

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