UFT is Unsolicited File Transfer; SIFT is Sender-Initiated
File Transfer.
They're the two sides of Internet SENDFILE.
The word "unsolicited" carries the
unfortunate implication
that files sent with UFT are unwanted. But this is not the case.
Files are unsolicited only in that the recipient did not
initiate the transfer.
The one receiving the file
did not "solicit" its delivery directly.
The UFT protocol ...
What's the difference between UFT and SIFT?
When UFT operates "on the wire" (that is, over TCP/IP)
it is referred to as just UFT.
When the same transaction is carried over mail,
it may be called SIFT. Otherwise, they are the same.
In fact, a major goal of implementors is that a transaction
be directly translatable between the two modes.
UFT protocol is suitable for transferring a wide range of
object types, including electronic mail and print.
Most often, UFT is used to send source code, data files,
large files, or any non-correspondence.
UFT provides at least the same level of file transfer
function as is found in
IBM NJE software sucn as RSCS.
Additionally, UFT is a "good Internet protocol".
A list of most of the objectives of UFT would include:
This leads to another point:
MIME effectively enhances e-mail in several ways, particularly in getting non-text through the network. Why not just use MIME to send files?
Worse, some MIME Content Types can vary in how they should be delivered; that is, they're textual one time and binary the next. For example, Application/PGP might need to be sent as plain text, or it might need to be sent as binary, even though it's always processed by the same agent on both ends of the transaction.
Make no mistake about it: We're not knocking MIME. We're not knocking the worldwide e-mail infrastructure. We're just saying that sometimes one needs a freight delivery service rather than a letter carrier.
UFT is intended to work like IBM's NJE networking, and NJE
can be carried over IP.
So why not just use NJE over IP?
Also, NJE is store-and-forward. UFT is direct.
Why not just use FTP to send files?
Because any time you use FTP to send files anonymously,
you run into a number of significant administrative "problems".
Please understand that UFT/SIFT isn't expected to replace
MIME, FTP, or NJE.
It is just hoped that it will augment
the standard TCP/IP suite of tools and protocols. As the
variety of protocols used on the web allow for achievable
"anonymous get", SIFT/UFT provides "anonymous put".
UFT has been implemented
in C for UNIX (POSIX)
and
in REXX with CMS Pipelines for VM.
UFT has also been implemented in
Tcl 7.5 as proof of concept.
(The Tcl version doesn't handle binary files without
help from the C version, but this is Tcl's fault, not UFT's.)
To illustrate a simple one-shot file transfer: a UFT client connects to a UFT server, sends a series of commands waiting for acknowledgements, and closes the connection. UFT transactions are carried out over TCP with the server listening on port 608. Most of the commands costitute a "meta file" of attributes of the real file. The real file, referred to as the "body" or "data file", is sent as a stream of octets. The octets are canonicalized from local convention on the sending side to an agreed format for transport and then restored to local convention on the receiving side (where representation may be different than for the sender).
© Copyright 1995, Richard M. Troth, all rights reserved.
Rick Troth <troth@casita.houston.tx.us>
Inspired by BITNET, which carried non-mail distinctly from mail, and by FRED, which was never developed though it was well conceived, and by LPR/LPD, FTP, and SMTP.