NAME

       bwctld - Bandwidth Control server.

SYNOPSIS

       bwctld  [  -a  auth_mode ] [ -c conf_dir ] [ -e facility ] [ -f ] [ -G group ] [ -h ] [ -R
       var_dir ] [ -S nodename:port ] [ -U user ] [ -Z ]

DESCRIPTION

       bwctld is a server  program  designed  to  schedule  and  run  Iperf,  Thrulay  or  Nuttcp
       throughput  tests.  These  tests  can  measure maximum TCP bandwidth, with various tunable
       options available, or, by doing a UDP test, he  delay,  jitter  and  datagram  loss  of  a
       network.

       Aside  from actually running throughput tests, the main function of bwctld is to determine
       which tests are allowable based upon the policy  restrictions  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 connection.

              E      [E]ncrypted. This mode encrypts the control connection. If the test supports
                     encryption, this mode will additionally encrypt the test stream. (Encryption
                     of  the  test  stream  is not currently supported, so this mode is currently
                     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.

       -e facility
              Syslog facility to which messages are logged.

              Default:
                     LOG_DAEMON

       -f     Enables the bwctld daemon 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.

       -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  specified,
              note  that  the  accepted  format  contains  nodename  in square brackets, such as:
              [fe80::fe9f:62d8]. This ensures the  port  number  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.

       -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 local clock. If those system calls are unavailable, or  the  administrator
       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
       eventually 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://sourceforge.net/projects/iperf web site.

       For details on Nuttcp, see the http://www.wcisd.hpc.mil/nuttcp/Nuttcp-HOWTO.html web site.

       For details on Thrulay, see the http://e2epi.internet2.edu/thrulay/ web site.

ACKNOWLEDGMENTS

       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.

                      $Date: 2009-02-23 08:08:04 -0500 (Mon, 23 Feb 2009) $             bwctld(8)