|
TFTP Overview, History and Standards
(Page 3 of 3)
Overview of TFTP Operation
Communication and messaging in TFTP
is very different than it is in FTP because of the different transport
layer protocols used by each. FTP makes use of TCP's rich functionality,
including its stream data orientation, to allow it to send bytes of
data directly over the FTP data connection. TCP also takes care of reliable
delivery of data for FTP, ensuring files are received correctly. In
contrast, since TFTP uses UDP, it must package data into individual
messages for both protocol control and data communication. TFTP must
also take care of timing transmissions to detect lost datagrams and
then retransmitting as needed.
TFTP servers allow connections from
TFTP clients to perform file send and receive operations. Many hosts
that run FTP servers will also run a separate TFTP server module as
well. TFTP users initiate connections by starting a TFTP client program,
which generally uses a command-line interface similar to that of many
FTP clients; the main difference is the much smaller number of commands
in TFTP.
 Key Concept: For situations where the full File Transfer Protocol (FTP) is either unnecessary or impractical, the simpler Trivial File Transfer Protocol (TFTP) was developed. TFTP is like FTP in that it is used for general file transfer between a client and server device, but it is stripped down in its capabilities. Rather than including a full command set and using TCP for communication like FTP, TFTP can only be used for reading or writing a single file, and uses the fast but unreliable UDP for transport. It is often preferred in situations where small files must be transferred quickly and simply, such as bootstrapping diskless workstations.
|
TFTP Option Extension and TFTP Options
The basic operation of TFTP has not
changed since RFC 1350 was published, but a new feature was added to
the protocol in 1995. RFC 1782, TFTP Option Extension,
defines a mechanism by which a TFTP client and TFTP server can negotiate
certain parameters that will control a file transfer prior to the transfer
commencing. This allows more flexibility in how TFTP is used, adding
a slight amount of complexity to TFTP, but not a great deal.
The option extension is backwards-compatible
with regular TFTP, and is only used if both server and client support
it. Two subsequent RFCs define the actual options that can be negotiated:
RFC 1783, TFTP Blocksize Option and RFC 1784, TFTP
Timeout Interval and Transfer Size Options. This set of three
RFCs (1782, 1783 and 1784) was replaced in 1998 by updated versions
in RFCs 2347, 2348 and 2349.
| If you find The TCP/IP Guide useful, please consider making a small Paypal donation to help the site, using one of the buttons below. You can also donate a custom amount using the far right button (not less than $1 please, or PayPal gets most/all of your money!) In lieu of a larger donation, you may wish to consider purchasing a download license of The TCP/IP Guide. Thanks for your support! |
|
|
Home -
Table Of Contents - Contact Us
The TCP/IP Guide (http://www.TCPIPGuide.com)
Version 3.0 - Version Date: September 20, 2005
© Copyright 2001-2005 Charles M. Kozierok. All Rights Reserved.
Not responsible for any loss resulting from the use of this site.
|
