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<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook V4.2//EN" [
<!-- define some ENTITYs -->
<!ENTITY fsp "File Service Protocol">
]>
<article id="fsp-faq" lang="en">
<articleinfo>
<title>FSP - &fsp; FAQ</title>
<author>
<firstname>Sven</firstname>
<othername>"Hoaxter"</othername>
<surname>Hoexter</surname>
<affiliation>
<address><email>sven@du-gehoerst-mir.de-nospam</email></address>
</affiliation>
</author>
<author>
<firstname>Radim</firstname>
<othername>"HSN"</othername>
<surname>Kolar</surname>
<affiliation>
<address><email>hsn@no.spam.sendmail.cz</email></address>
</affiliation>
</author>
<copyright>
<year>2003-2004</year>
<holder>Authors</holder>
</copyright>
<revhistory>
<revision>
<revnumber>0.2</revnumber>
<date>2005.01.03</date>
</revision>
</revhistory>
<!-- starting with some general stuff -->
<abstract>
<para>
This document is a major rewrite of the old
<ulink url="http://fsp.sourceforge.net/doc/faq.html">FSP FAQ</ulink>.
I started with this FAQ from scratch cause nearly all parts of the old FAQ where outdated. This new FAQ is maintained
in DocBook SGML. Send patches to the fsp-devel Mailinglist (FIXME link to id gethelpml) or directly to me
<email>sven@du-gehoerst-mir.de-nospam</email>. You should be able to find the latest SGML version of this FAQ in the
<ulink url="http://sourceforge.net/cvs/?group_id=93841">fsp CVS at sf.net</ulink> or here
<ulink url="http://sven.stormbind.net/fsp/fsp-doc/fsp-faq.sgml">http://sven.stormbind.net/fsp/fsp-doc/fsp-faq.sgml</ulink>
(be aware the sf.net public CVS is often about a week behind the "real" CVS :( )
</para>
</abstract>
</articleinfo>
<!-- end of the general stuff -->
<!-- starting with the main document -->
<!-- starting with the introduction -->
<sect1 id="introduction">
<title>Introduction</title>
<sect2 id="whatisfsp">
<title>What is FSP?</title>
<para>
FSP stands for &fsp;. In general FSP is what anonymous ftp should be: a reliable and bandwidth friendly
way to access publicly available data.
<para>
FSP is a lightweight UDP based protocol for transferring files around.
It has many benefits over FTP, mainly for running
anonymous archives. FSP protocol is valuable in all kinds of
environments because it is one of the only TCP/IP protocols that is not
aggressive about bandwidth, while still being sufficiently fault tolerant.
</para>
</sect2>
<sect2 id="fsp-project">
<title>FSP Project</title>
<para>
FSP is (and always has been) open source project with MIT/X11 source
code license. See <xref linkend="licence"> for more details.
<para>
In the past various people maintained the FSP code base.
At the moment Radim Kolar
is maintaining FSP. FSP project is now hosted on
<ulink url="http://sourceforge.net">Source Forge.NET</ulink>.
<para>
If you like to get involved take a look at the FSP
<ulink url="http://fsp.sourceforge.net">Homepage</ulink> and the
<ulink url="http://www.sourceforge.net/projects/fsp/">FSP project page</ulink>.
</para>
</sect2>
<sect2 id="whatisitfor">
<title>Why and for what should I use FSP?</title>
<para>
The &fsp; has its strengths on slow lines and connections with a high packets lose like a Wireless LAN or radio packet networks. Because FSP is simple
and lightweight, it is very well suited for use in embedded devices area.
<para>
FSP protocol is not aggressive about bandwidth and was designed
to resist against users which want to do some bandwidth-related attacks.
It can support more users, because the same available
bandwidth is divided into smaller parts.
Because FSP uses less bandwidth, FSP transfers takes about
2-3 times longer than with TCP-based protocols.
<para>
FSP protocol
chooses reliability and simplicity over raw transfer speed.
File transfer takes longer, but there are much more resistant
against network failure.
<para>
Entire connection management is moved from server to client side,
which solves problems with aborted and timed out transfer. Because
FSP is stateless protocol, it can survive even server reboot without
interruption.
<para>
More information about FSP use can be found
in <ulink url="http://cvs.sourceforge.net/viewcvs.py/fsp/fsp/INFO?view=auto">INFO document</ulink>.
</para>
</sect2>
<sect2 id="comparison">
<title>Comparison between fsp and other protocols</title>
<para>
We did some benchmarking so that you can see how fsp performance
compared to various other command protocols used to transfer
files.
<sect2 id="benchresults">
<title>Benchmark results</title>
<para>
You should understand that FSP is slower than TCP
based protocols by design. TCP protocol can have more than
one packet flying in network (usually 2-3) while FSP was designed to
make it impossible (See <xref linkend="keying">).
<para>
All TCP protocols have on normal networks
(max 10% packet loss) higher transfer rate than FSP.
FSP is clean winner when it comes to overloaded sites or lines.
These benchmarks were performed on 10Mbit LAN with zero traffic.
Transfer rate is quite slow even for 10Mb because one of testing
machines was old AMD K5/90 and both machines used cheap clone ISA NE2000 Ethernet cards.
<para>Test file was 3656535 bytes long (FreeBSD kernel image).
Test results shows, that FSP is about 2-2.5 times slower than TCP.
<programlisting>
tftp 15.2 secs 240.6 kB/s
ftp 5.18 secs 688.7 kB/s
http 5.32 secs 685.4 KB/s
sftp 8.0 secs 446.4 KB/s
fsp 12.7 secs 287.7 kB/s
</programlisting>
</para>
<sect3 id="comparehttp">
<title>FSP vs. http</title>
<para>
HTTP: widely supported by servers, clients and proxies.
De-facto standard protocol for accessing information today.
HTTP is also primary protocol used for file distribution today.
<para>
FSP: Can provide directory listings, which are not supported
by standard HTTP/1.1 protocol. You need to have configured
WebDAV server-side extension for that.
</para>
</sect3>
<sect3 id="compareftp">
<title>FSP vs. ftp</title>
<para>
FTP: widely supported by servers and clients, more difficult
to proxy than HTTP, uses 2 TCP connections, can provide directory
listings in site-specific format, server side is more heavy service
than HTTP. FTP is being replaced by HTTP today.
<para>
FSP: do not needs to make any connection, server side is very
lightweight service,
directory listings are standardized by protocol and very quick,
no problems with NAT.
</sect3>
<sect3 id="comparetftp">
<title>FSP vs. tftp</title>
<para>
tftp is simple UDP (but TCP version also exists) protocol used mainly
for loading boot and flash ROM images from network. Standard
tftp uses 512 bytes long packets.
<para>
TFTP: more widely used, standardized in RFC, most network cards
can boot image via TFTP.
<para>
FSP: about 1.5-times faster because of 1k-1.4k packet size,
supports directory listings,
can query file date and size,
can provide random access to file and supports opening
more than one file, supports access control, timeout
management moved to client side, stateless.
</para>
</sect3>
</sect2>
<sect2 id="whyfspd">
<title>Why should I run fspd?</title>
<para>
If you are providing anonymous archive (FTP,WWW), you should also
offer FSP access. FSP daemon is a very lightweight process, never
forks and you will never have more than one copy running around.
On todays machines, it has zero performance impact.
<para>
Running fspd allows people with overloaded or lousy lines to get
files from your archive. It also helps people during spikes periods
when archive is very busy.
<para>
There are also some people which likes slower FSP downloads better,
because
it saves their bandwidth for interactive tasks. This is often preferred
way of downloading large files, like CD-ROM images.
<para>
It is not true that UDP based protocols are unsecure. &fsp; provides
the same security level as anonymous FTP and is much more resistant
against denial of service attacks. It is nearly impossible to overload
fsp server by flooding. On other side, TCP-based protocols are very
simple to SYN flood.
<sect2 id="wherecanifind">
<title>Where can I download FSP?</title>
<para>
You can Download the FSP source Distribution from the
<ulink url="http://sourceforge.net/project/showfiles.php?group_id=93841">sf.net mirror network</ulink>
or from
<ulink url="http://ibiblio.org/pub/linux/system/network/file-transfer/">ibblio</ulink>.
If you have the FSP tools already you can access the latest FSP release
via fsp on hxt.homelinux.org or wrack.telelev.net both running fspd on
port 2221.
</para>
<para>
When you're interested in the latest, and of course greatest,
development done in FSP please try a CVS checkout.
Explanation and all needed information to do this can be found
on the
<ulink url="http://sourceforge.net/cvs/?group_id=93841">sf.net CVS page</ulink>.
</sect2>
<sect2 id="gethelp">
<title>Where can I find help?</title>
<para>
First of all various people took the time to write nice documentation on FSP including the fspd Server
and the client tools. Please read those fine documents before you start writing to the mailinglists.
</para>
<sect3 id="gethelpdocs">
<title>RTFM - Read the fine Manuals</title>
<para>
<ulink url="http://fsp.sourceforge.net/doc/PROTOCOL.txt">The &fsp; definition</ulink>
The latest version of the FAQ,
The <ulink url="http://fsp.sourceforge.net/doc/faq.html">old FSP FAQ</ulink>.
</para>
</sect3>
<sect3 id="gethelpml">
<title>The Mailinglists</title>
<para>
For developing issue write to the fsp-dev mainlinglist. For end-user questions
and questions on how to configure your server/client write to the fsp-user Mailinglist.
You can find more information on how to subscribe/unsubscribe to the mailinglist and
the archive on the
<ulink url="http://sourceforge.net/mail/?group_id=93841">FSP mailinglist page</ulink>
on sf.net.
Please before you write to one of the provided mailinglists read and understand
<ulink url="http://www.catb.org/~esr/faqs/smart-questions.html">ESRs HowTo ask smart questions</ulink>
and
<ulink url="http://www.netmeister.org/news/learn2quote.html">learn.to/quote</ulink>
</para>
</sect3>
</sect2>
<sect2 id="licence">
<title>Licence, copyright and redistribution of FSP</title>
<para>
FSP code base uses MIT/X11 license (also known as 2-point BSD
license). This license is very friendly to users in commercional area.
You can freely develop, use and sell your commercional implementation of &fsp;.
<orderedlist>
<listitem>
<para>Do not claim that you have wrote this software.
</listitem>
<listitem>
<para>Do not sue us if something breaks.
</listitem>
</orderedlist>
Summary: As long as you will not remove our copyrights from source code
and will not go with your complains to the court, you can
do with this software anything you want.
</para>
<para>
From the COPYRIGHT file in the source distribution (e-mail addresses removed):
<programlisting>
Authors:
Radim Kolar (Current FSP maintainer)
Andrew Doherty
Michael Fischbein
Cimarron D. Taylor
Guido van Rossum
Wen-King Su
Philip G. Richards
Michael Meskes
Rich $alz
gjc@mitech.com
Joseph_Traub
Sven (VMS port maintainer)
Very Mad Students, University of Karlsruhe, FRG (VMS port)
Copyright:
All of the FSP code is free software. Most of fsp falls under two
copyrights, the 2-point BSD copyright and one by Wen-King Su:
Copyright (c) 1991 by Wen-King Su (wen-king@vlsi.cs.caltech.edu)
You may copy or modify this file in any manner you wish, provided
that this notice is always included, and that you hold the author
harmless for any loss or damage resulting from the installation or
use of this software.
Other contributions to fsp fall under different copyrights:
This file is Copyright 1992 by Philip G. Richards. All Rights Reserved.
See the file README that came with this distribution for permissions on
code usage, copying, and distribution. It comes with absolutely no warranty.
Copyright (c) 1993 by Michael Meskes
You may copy or modify this file in any manner you wish, provided
that this notice is always included, and that you hold the author
harmless for any loss or damage resulting from the installation or
use of this software.
</programlisting>
</para>
</sect2>
<sect2 id="projecthistory">
<title>Project history</title>
<para>
This should give you a short overview over the development of the &fsp;
in the past and today.
</para>
<sect3 id="histpast">
<title>The past</title>
<para>
FSP development started in a very old days. From source code and man
page time stamps we can see that it was working and alive in 1988.
FSP versions 1.0 and 2.0 was born in Dec 1991. Release 2.0 was just
bufixed 1.0 but includes man pages. After that two first
releases FSP goes to the active life. People starts using it because
it was superior to anonymous FTP at that time.
<para>
FSP active development era ends in May 1993 when last official
version 2.7.1 was released. It was quite popular at that time,
mainly because it was superior way for transferring warez around
when compared with FTP. Because of this, FSP protocol got a bad
name "Underground file sharing protocol" and suffers from it even today.
I see that FSP warez era
as practical demonstration how can FSP perform nicely on
overloaded sites and lines.
<para>
After that then was some maintenance work on FSP in 1995 which ends
with famous last official beta FSP version 2.8.1b3
in March 1996, which was coded by original FSP developers team.
This version is used on some servers today because Debian Woody has it.
<para>
Last official stable FSP version was still 2.7.1 from May '93.
This is still used on some forgotten machines in universities today.
It has also
known security issue (fspd follows all symlinks), but at this
time this was viewed as feature, not a bug.
<para>
Radim Kolar released 2.8.1b4 in 2001, which was just some bugfixed
version of 2.8.1b3 untouched from 1997 when I ported it to OS/2.
<para>
With wireless networks Wi-Fi boom in 2002, it becomes clear that
large wireless networks can have quite a high packet loss rate
and TCP protocol is not very suitable for them.
<para>
Active working on FSP again starts on 25 June 2003 when Version
2.8.1b5 goes out. Major parts of FSP server code was rewrited
for higher performance and many old bugs in FSP code fixed.
Some bugs gets fixed after more than 10 years.
<para>
In the past various people worked on the &fsp;, see
<xref linkend="licence">
</para>
</sect3>
<sect3 id="histtoday">
<title>Today</title>
<para>
Radim Kolar started to work on the &fsp; again in June 2003. Since
that time he's maintaining the source distribution. You can reach him
on the mailinglists or via e-mail <email>hsn@no.spam.sendmail.cz</email>.
</para>
<para>
Since September 2003 Sven Hoexter is working on parts of the documentation and code. He is also doing release management and RPM, deb packaging.
You can reach him on the mailinglists or via e-mail
<email>sven@du-gehoerst-mir.de-nospam</email>.
</sect2>
<sect2 id="credits">
<title>Developers and contributors</title>
<para>
See <xref linkend="licence">
</para>
</sect2>
</sect1>
<!-- end of the introduction -->
<!-- start with the installation instructions-->
<sect1 id="installation">
<title>Installation instructions</title>
<sect2 id="getfsp">
<title>How to get FSP</title>
<sect3 id="getsource">
<title>How to obtain the source distribution</title>
<para>
There are several ways to obtain the fsp source distribution please take a
look at <xref linkend="wherecanifind">
</para>
</sect3>
<sect3 id="getbinary">
<title>How to obtain a binary copy</title>
<para>
At the moment we provide only RPM for RedHat 7.3. You can download the RPM file from
the sf.net download page or from wrack.telelev.net. wrack.telelev.net provides the
rpms in a apt-rpm usable way, for more information about apt-rpm and the packages on
wrack.telelev.net take a look at http://sven.stormbind.net/aptrpm/
If you're running other rpm based distributions you can try to rebuild the source rpms.
</para>
</sect3>
</sect2>
<sect2 id="compilesource">
<title>How to compile the source code</title>
<para>
After download you should be able to unpack the source tarball, change
into the source directory and use
./configure
make
su
make install
</para>
</sect2>
</sect1>
<!-- end of the installation instructions -->
<!-- start how to use on the server side -->
<sect1 id="serverside">
<title>How to set up your FSP server</title>
<para>
Setting FSP server is a easy task. Majority of people runs FSP
server in read only mode. In this mode fspd needs to know
only home directory and port number. Both can be supplied by command
line arguments to fspd.
<para>
If you need additional features, such as
logging, you will need to have <xref linkend="fspd.conf">
</para>
<sect2 id="installserver">
<title>How to install fsp server</title>
<para>
FSP server is included in main FSP package. See <xref linkend="installation"> first. FSP server for windows is in the <xref linkend="lamerpack">.
<para>
Server can be installed as inetd service or standalone. I prefer
inetd installation, because modification of system startup
scripts is not needed.
<para>
Server can operate even without user supplied configuration file
fspd.conf. Basic setup can be easily done by command line arguments.
</sect2>
<sect2 id="installfspdquick">
<title>How to quickly install fsp server</title>
<para>
Add following line to your /etc/inetd.conf
<programlisting>
ftp dgram udp wait ftp /usr/local/bin/fspd in.fspd -d /home/ftp
</programlisting>
This easy setup will run fsp server on standard port 21, home directory set to /home/ftp and effective user set to ftp. If you do not have configured
temporary directory in fspd.conf, fsp server will run in read-only
mode.
<para>
Some inetd server uses slightly different syntax of inetd.conf
file. Consult your local man pages for inetd and inetd.conf.
<sect2 id="fspd.conf">
<title>How to setup a basic fspd.conf</title>
<para>
Example config file for fsp server is called fspd.conf and can be
found in distribution. This file needs to be installed as
/usr/local/etc/fspd.conf or you can specify alternate location
by -f command line switch passed to fspd.
<para>
Configuration file itself is commented. Read comments inside.
</para>
</sect2>
<sect2 id="initscript">
<title>How can I start the fspd automagicly on reboot?</title>
<para>
FIXME.
Use init scripts ;) or run it from inetd.
</para>
</sect2>
<sect2 id="restrictions">
<title>How to setup restrictions on directories?</title>
<para>
FIXME.
See manual page fspd(1).
</para>
</sect2>
</sect1>
<!-- end how to use the server -->
<!-- start how to use on the client side -->
<sect1 id="clientside">
<title>How to use the fsp client tools</title>
<para>
For accessing FSP server, you need to use programs which supports
FSP v2 protocol. There are several programs available today.
</para>
<sect2 id="fsptoolchain">
<title>The fsp tool collection</title>
<para>
Classic command line interfacing with FSP server is via client
utilities found in basic distribution. Because FSP protocol
do not uses connections, there is no central command line interpreter
like found in ftp, because it is not needed. Information about
current remote server address and remote working directory is kept
in several environment variables. See manual page fsp_env for more
info.
<para>
Fsp client commands are started from normal shell interpreter. Because
most commands does remote globing which can not be done by your
local shell, you will need to turn globing in your shell off or
use one of prepared shell aliases. In distribution you will find
setup.sh and setup.csh shell scripts. These scripts must be
sourced (not executed) by your current shell.
<para>
Fsp commands names follows unix standard with f prepended. For
example: fcd, fpwd, fls. Files are transfered by fget/fput commands.
</para>
</sect2>
<sect2 id="fspclient">
<title>fspclient</title>
<para>
FSP Client is FTP-like interface for FSP.
It look exactly like classic FTP does, but uses different transfer
protocol. People usually find this program easier to use that
multiple client programs in FSP protocol suite. If you are at least
somewhat familiar with command line FTP and want to try FSP, this
program is right for you.
<para>
The old, real hackers prefers <xref linkend="fsptoolchain">, because
fspclient is just 'fsp for lamah'.
<para>
FSP client homepage is <ulink url="http://fspclient.sourceforge.net">http://fspclient.sourceforge.net</ulink>.
</para>
</sect2>
<sect2 id="gui">
<title>FSP PROXY: Using FSP in browser</title>
<para>
If you want a GUI, the easiest way is to use FSP directly
from your web browser. This is recommended method for using FSP
by standard BFU users. They can handle web browser well -- no
extra education is necessary.
<para>
You need to download and install <ulink url="http://fsp.sf.net/javalib.html">FSP Java LIB</ulink> and <ulink url="http://fsp.sf.net/fsproxy.html">Proxy server</ulink>. Read included docs for install instructions.
<sect2 id="dmachine">
<title>Download Machine</title>
<para>
Download Machine is non interactive, non graphical, batch download
manager. Tired of GUI Download managers and mouse clicking?
Then Download Machine is just for YOU!
<para>
Download Machine is written in portable Java 1.1 code and supports
<ulink url="http://www.w3.org/Protocols/">HTTP</ulink>,
FTP and <ulink url="http://fsp.sourceforge.net/">FSP</ulink>
protocols.
<sect2 id="lamerpack">
<title>FSP Win32 Suite</title>
<para>
Special, easy to use, starting suite targeted at common Windows users.
Suite contains 3 valueable items:
Easy to use fsp server (works without configration file),
windows version of fspclient and
Lamah starting guide to FSP.
<para>
This package is downloadable from
<ulink url="http://sourceforge.net/project/showfiles.php?group_id=93841&amp;package_id=133839">Source Forge</ulink> and requires cygwin dll library
not included in the package.
</sect1>
<!-- end how to use the client -->
<sect1 id="techinfo">
<title>FSP technology in-depth</title>
<sect2 id="protocol">
<title>Protocol definition document</title>
<para>
FSP protocol is well documented.
You can find the latest protocol definition right here
<ulink url="http://fsp.sourceforge.net/doc/PROTOCOL.txt">http://fsp.sourceforge.net/doc/PROTOCOL.txt</ulink>
or in the source distribution in the "doc" subdirectory.
</para>
<sect2 id="transport">
<title>Transport mechanism used by FSP</title>
<para>
FSP is datagram-based protocol. FSP protocol itself do not require
reliable underlying transport. FSP can operate even without
any Layer 2 and Layer 3 transports only with some extra features
disabled. FSP can be implemented in all kinds of environments.
This makes FSP very suitable for embedded devices area, because
it is easier to implement than other transfer protocols like X-Modem.
<para>
When used in TCP/IP based networks,
UDP is used for transporting of FSP datagrams, this lowers protocol
overhead by skipping TCP level, which is not needed, because FSP
handles connection management by itself. This method is standardized
in <xref linkend="protocol">.
</para>
<para>
FSP frames can be packed directly info Ethernet 802.2, USB or GSM
frames. Biggest advantage of using FSP in that areas is simplicity.
FSP protocol is very simple to implement.
</sect2>
<sect2 id="keying">
<title>Keying: Network bandwidth protection</title>
<para>
One of interesting parts of underlying network technology used
by FSP is how protocol design restrict user from sending
more than one packet into network.
<para>
FSP uses very simple method: Every packet sent from server to client
contains a 16-bit long, pseudo random key. Client needs this key
for sending next request to server. Server will ignore requests
with wrong key, unless there was no previous activity recorded
for client IP address in last 60 seconds.
<para>
Server remembers for each IP not only nextkey, but also previous
key. When packet's key matches previously stored key -- it is
resend from client. Server limits replies to resend packets also.
Max. allowed reply rate to resend packets is 1 reply per 3 seconds.
This method also allows ignore duplicate requests by server for
action which should not be done more than once (for example mkdir).
<para>
In each packet sent by client to server is sequence number.
Server will echo this number back to the client, when packet is
processed. There is no restriction on that number, client can
use anything he wants.
Primary purpose
of this sequence number is possibility to put unique mark on
every network packet. Client can use this information and
fine-tune its retry algorithm
by computing packet loss ratio of network, and duplicate
packet rate.
<sect2>
<title>Client side locking</title>
<para>
FSP server has its secret keys database divided by client ip address,
not by client:port. All requests comming from the same machine must
shares the same secret key. This is done for bandwidth protection.
<para>
Client must submit a valid key with request. Where there are 2 programs
runnings on the client PC and both wants to talk to the same FSPD at once,
they must exchange knowledge of this secret key between themselfs.
If they don't, only one program can talk to the FSPD, because others do not
knows the next session key. They can try to talk but fspd will ignore them.
This is kind of client-side multiplexing.
<para>
There are several methods how to do this key sharing. Best method is
to use semop+shmget, second is to use lockf on file in /tmp. All FSP
clients running on the same machine must use the same locking method.
<sect2 id="largepackets">
<title>Why not use bigger packet size?</title>
<para>
&fsp; defines maximum packet size 1024 bytes of data + header.
All FSP compatible protocol stacks must support this packet size.
Nearly all networks can transfer 1036 bytes long UDP packets.
Some networks allows only 512 bytes long UDP (maximal size required
by RFC). To use FSP on that networks, fsp clients must be configured
to use only 500 bytes of payload.
<para>
Because MTU of most networks is about 1500 bytes. It is true, that
we can use slightly bigger packets for gaining some speed. FSP
server can optionally support larger packet size, but must send
them out only on explicit client request.
<para>
We have performed some benchmarks and they shows only minor
performance increase, about 10-15 percent. Similar testing
was performed by HP in <ulink url="http://www.ietf.org/rfc/rfc2348.txt">RFC 2348</ulink>.
<para>
For bigger performance enhancement we need to use at least 2.5 KB,
but packets of that size must be fragmented on most network and fragmenting increases possibility of packet loss.
<sect2 id="prog">
<title>Using FSP in your programs</title>
<para>
You can easily add support for FSP v2 protocol into your programs.
Currently exists two independend libraries for FSP protocol support
and one library is in the work.
<para>
First library is called <ulink url="http://fsp.sourceforge.net/javalib.html">JFSPlib</ulink>. This is FSP library for Java language.
<para>
Second library is called <ulink url="http://fsp.sourceforge.net/fsplib.html">FSPlib</ulink>. This is FSP library for C language with POSIX-like API.
<para>
FSP support for Python <ulink url="http://fsp.sourceforge.net/pyfsp.html">PyFSP</ulink> is currently work in progress. Note: PyFSP uses GPL license, not MIT/X11 like other libraries.
<sect2 id="faster">
<title>How can I make FSP faster?</title>
<para>
Set FSP server and client to use bigger block size (<xref linkend="largepackets">), decrease server retry timeout to 1 sec, and descrease client delay also. Using this methods, FSP can run about 1.7 faster than before.
If you need even higher transfer speed, switch to HTTP protocol.
<sect2 id="slower">
<title>How can I make FSP slower?</title>
<para>
If your FSP server eats too much bandwidth, the best is to use
smaller packets. FSP server has builtin output thruput limiting, you
can slow down it in fspd.conf file. Slightly increasing server retry
timer also helps.
</sect1>
</article>
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