TFTP Windowsize Option
RFC 7440
| Document | Type |
RFC - Proposed Standard
(January 2015; No errata)
Was draft-masotta-tftpexts-windowsize-opt (individual)
|
|
|---|---|---|---|
| Last updated | 2015-10-14 | ||
| Stream | IETF | ||
| Formats | plain text pdf html bibtex | ||
| Reviews | |||
| IETF conflict review | conflict-review-masotta-tftpexts-windowsize-opt | ||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Joel Jaeggli | ||
| Shepherd write-up | Show (last changed 2014-09-01) | ||
| IESG | IESG state | RFC 7440 (Proposed Standard) | |
| Consensus Boilerplate | Yes | ||
| Telechat date | |||
| Responsible AD | Joel Jaeggli | ||
| Send notices to | (None) | ||
| IANA | IANA review state | IANA OK - No Actions Needed | |
| IANA action state | No IC | ||
Internet Engineering Task Force (IETF) P. Masotta
Request for Comments: 7440 Serva
Category: Standards Track January 2015
ISSN: 2070-1721
TFTP Windowsize Option
Abstract
The "Trivial File Transfer Protocol" (RFC 1350) is a simple,
lockstep, file transfer protocol that allows a client to get or put a
file onto a remote host. One of its primary uses is in the early
stages of nodes booting from a Local Area Network (LAN). TFTP has
been used for this application because it is very simple to
implement. The employment of a lockstep scheme limits throughput
when used on a LAN.
This document describes a TFTP option that allows the client and
server to negotiate a window size of consecutive blocks to send as an
alternative for replacing the single-block lockstep schema. The TFTP
option mechanism employed is described in "TFTP Option Extension"
(RFC 2347).
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7440.
Masotta Standards Track [Page 1]
RFC 7440 TFTP Windowsize Option January 2015
Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction ....................................................2
2. Conventions Used in This Document ...............................3
3. Windowsize Option Specification .................................3
4. Traffic Flow and Error Handling .................................4
5. Proof of Concept and Windowsize Evaluation ......................6
6. Congestion and Error Control ....................................7
7. Security Considerations .........................................8
8. References ......................................................9
8.1. Normative References .......................................9
Author's Address ...................................................9
1. Introduction
TFTP is virtually unused for Internet transfers today, TFTP is still
massively used in network boot/installation scenarios including EFI
(Extensible Firmware Interface). TFTP's inherently low transfer rate
has been, so far, partially mitigated by the use of the blocksize
negotiated extension [RFC2348]. Using this method, the original
limitation of 512-byte blocks are, in practice, replaced in Ethernet
environments by blocks no larger than 1468 Bytes to avoid IP block
fragmentation. This strategy produces insufficient results when
transferring big files, for example, the initial ramdisk of Linux
distributions or the PE images used in network installations by
Microsoft WDS/MDT/SCCM. Considering TFTP looks far from extinction
today, this document presents a negotiated extension, under the terms
of the "TFTP Option Extension" [RFC2347], that produces TFTP transfer
rates comparable to those achieved by modern file transfer protocols.
Masotta Standards Track [Page 2]
RFC 7440 TFTP Windowsize Option January 2015
2. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
[RFC2119].
In this document, these words will appear with that interpretation
only when in ALL CAPS. Lowercase uses of these words are not to be
interpreted as carrying the significance given in RFC 2119.
3. Windowsize Option Specification
The TFTP Read Request or Write Request packet is modified to include
the windowsize option as follows. Note that all fields except "opc"
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