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Bandwidth Test Controller (BWCTL)
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bwctld(8) Manual Page
bwctld(8) bwctld(8)
NAME
bwctld - Bandwidth Control server.
SYNOPSIS
bwctld [ -a auth_mode ] [ -c conf_dir ] [ -d data_dir ] [ -e facility ]
[ -f ] [ -G group ] [ -h ] [ -R var_dir ] [ -S nodename:port ] [ -U
user ] [ -v ] [ -Z ]
DESCRIPTION
bwctld is a server program designed to schedule and run Iperf through-
put tests.
From the Iperf web site:
Iperf is a tool to measure maximum TCP bandwidth, allowing the
tuning of various parameters and UDP characteristics. Iperf
reports bandwidth, delay jitter, datagram loss.
Aside from actually running Iperf tests, the main function of bwctld is
to determine which tests are allowable based upon the policy restric-
tions configured by the system administrator.
bwctld was designed to be run as a stand-alone daemon process. It uses
the classic accept/fork model of handling new requests.
Most of the command line options for bwctld have analogous options in
the bwctld.conf file. The command line takes precedence.
OPTIONS
-a auth_mode
Specify the authentication modes the server is willing to use
for communication. auth_mode should be set as a character string
with any or all of the characters "AEO". The modes are:
A [A]uthenticated. This mode encrypts the control connec-
tion.
E [E]ncrypted. This mode encrypts the control connection.
If the test supports encryption, this mode will addition-
ally encrypt the test stream. (Encryption of the test
stream is not currently supported, so this mode is cur-
rently identical to authenticated.)
O [O]pen. No encryption of any kind is done.
The server can specify all the modes with which it is willing to
communicate. The most strict mode that both the server and the
client are willing to use will be selected.
Default:
"AEO".
-c conf_dir
Specify the directory that holds the bwctld configuration files.
Default:
Current working directory.
-d data_dir
Specify the directory that holds the output data files. (bwctld
does not currently save the results of the Iperf tests. This
option is a place holder for when it does.)
Default:
Current working directory.
-e facility
Syslog facility to which messages are logged.
Default:
LOG_DAEMON
-f Disables the checks that disable bwctld if it is configured to
run with root permissions. There are legitimate reasons to run
bwctld as root, but it is risky. Forcing this additional option
will make it less likely root permissions are accidently used.
-Z Run the master bwctld process in the foreground. In this mode,
error messages are printed to stderr as well as being sent to
syslog. Also, normal terminal controls are available. (i.e.,
<Cntr-C> will cause the daemon to kill it's child processes and
exit.) This is useful for debugging.
REQUIREMENTS
The bwctld daemon prefers a reasonably synchronized clock. It is
scheduling tests and needs to be sure it has the same idea of when a
test should take place as does the peer test system. Therefore, bwctld
attempts to use NTP specific system calls to determine the accuracy of
the localclock. If those system calls are unavailable, or the adminis-
trator has set the allow_unsync option in the bwctld.conf file, then
bwctld will blindly accept tests assuming the clock is synchronized to
within the sync_fuzz value that is also defined in the bwctld.conf
file. If this assumption does not hold true, then the test will eventu-
ally fail. Unfortunately, because the time offset is not detected
early, this test will have taken up a schedule slot.
FILES
bwctld.pid
bwctld.conf
bwctld.limits
bwctld.keys
SEE ALSO
There are more details on configuring the bwctld daemon in the
bwctld.conf(5) manual page. Details on configuring the policy is in the
bwctld.limits(5) and bwctld.keys(5) manual pages. Information on the
client is in the bwctl(1) manual page. For more of an overview of the
full functionality and architecture see the
http://e2epi.internet2.edu/bwctl/ web site.
For details on Iperf, see the http://dast.nlanr.net/Projects/Iperf/ web
site.
ACKNOWLEDGMENTS
This material is based in part on work supported by the National Sci-
ence Foundation (NSF) under Grant No. ANI-0314723. Any opinions, find-
ings and conclusions or recommendations expressed in this material are
those of the author(s) and do not necessarily reflect the views of the
NSF.
Default:
LOG_DAEMON
-G group
Specify the gid for the bwctld process. group can be specified
using a valid group name or by using -gid. This option is only
used if bwctld is started as root.
-h Print a help message.
-R var_dir
Specify the directory to hold the bwctld.pid file.
Default:
Current directory
-S nodename:port
Specify the address and port on which bwctld will listen for
requests. nodename can be specified using a DNS name or using
the textual representation of the address. It is possible to set
the source address without setting the port simply by leaving
off the ':' and port specification. If an IPv6 address is speci-
fied, note that the accepted format contains nodename in square
brackets, such as: [fe80::fe9f:62d8]. This ensures the port num-
ber is distinct from the address specification.
Default:
nodename is wildcarded as any currently available
address. port is 4823.
-U user
Specify the uid for the bwctld process. user can be specified
using a valid user name or by using -uid. This option is only
used if bwctld is started as root.
-v Set verbose output. Messages will only go to syslog unless the
-Z option is specified.
-Z Run the master bwctld process in the foreground. In this mode,
error messages are printed to stderr as well as being sent to
syslog. Also, normal terminal controls are available. (i.e.,
<Cntr-C> will cause the daemon to kill it's child processes and
exit.) This is useful for debugging.
REQUIREMENTS
The bwctld daemon requires a reasonably synchronized clock. It is
scheduling tests and needs to be sure it has the same idea of when a
test should take place as does the peer system with which the test is
being done. Therefore, bwctld requires that NTP be running to synchro-
nize the system clock. This means that NTP needs to be setup correctly
on the system so that NTP can actually calculate a reasonable estimate
of the time error. For the NTP algorithms to work correctly, ntpd MUST
be configured with no fewer than 4 clocks.
FILES
bwctld.pid
bwctld.conf
bwctld.limits
bwctld.keys
SEE ALSO
There are more details on configuring the bwctld daemon in the
bwctld.conf(5) manual page. Details on configuring the policy is in the
bwctld.limits(5) and bwctld.keys(5) manual pages. Information on the
client is in the bwctl(1) manual page. For more of an overview of the
full functionality and architecture see the
http://e2epi.internet2.edu/bwctl/ web site.
For details on Iperf, see the http://dast.nlanr.net/Projects/Iperf/ web
site.
ACKNOWLEDGMENTS
This material is based in part on work supported by the National Sci-
ence Foundation (NSF) under Grant No. ANI-0314723. Any opinions, find-
ings and conclusions or recommendations expressed in this material are
those of the author(s) and do not necessarily reflect the views of the
NSF.
$Date: 2005/09/07 23:36:18 $ bwctld(8)
Man(1) output converted with
man2html
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| Bandwidth Test Controller (BWCTL) |
16 February, 2004 |
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This material is based, in part, on work supported by the National Science
Foundation (NSF) under Grant No. ANI-0314723. Any opinions, findings and conclusions or
recommendations expressed in this material are those of the author(s) and do not necessarily
reflect the views of the NSF.
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