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DUMMYNET(4)	       FreeBSD Kernel Interfaces Manual		   DUMMYNET(4)

NAME
     dummynet -- traffic shaper, bandwidth manager and delay emulator

DESCRIPTION
     The dummynet system facility permits the control of traffic going through
     the various network interfaces, by	applying bandwidth and queue size lim-
     itations, implementing different scheduling and queue management poli-
     cies, and emulating delays	and losses.

     The user interface	for dummynet is	implemented by the ipfw(8) utility, so
     please refer to the ipfw(8) manpage for a complete	description of the
     dummynet capabilities and how to use it.

   Kernel Options
     The following options in the kernel configuration file are	related	to
     dummynet operation:

	   IPFIREWALL		     enable ipfirewall (required for dummynet)
	   IPFIREWALL_VERBOSE	     enable firewall output
	   IPFIREWALL_VERBOSE_LIMIT  limit firewall output
	   DUMMYNET		     enable dummynet operation
	   HZ			     set the timer granularity

     Generally,	the following options are required:

	   options IPFIREWALL
	   options DUMMYNET
	   options HZ=1000	   # strongly recommended

     Additionally, one may want	to increase the	number of mbuf clusters	(used
     to	store network packets) according to the	sum of the bandwidth-delay
     products and queue	sizes of all configured	pipes.

SEE ALSO
     setsockopt(2), if_bridge(4), ip(4), ipfw(8), sysctl(8)

HISTORY
     The dummynet facility was initially implemented as	a testing tool for TCP
     congestion	control	by Luigi Rizzo <luigi@iet.unipi.it>, as	described on
     ACM Computer Communication	Review,	Jan.97 issue.  Later it	has been modi-
     fied to work at the IP and	bridging levels, integrated with the ipfw(4)
     packet filter, and	extended to support multiple queueing and scheduling
     policies.

FreeBSD	9.2		       October 28, 2002			   FreeBSD 9.2

NAME | DESCRIPTION | SEE ALSO | HISTORY

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<http://www.freebsd.org/cgi/man.cgi?query=dummynet&manpath=FreeBSD+10.0-RELEASE>

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