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)