1.\" 2.\" $FreeBSD$ 3.\" 4.Dd October 28, 2002 5.Dt DUMMYNET 4 6.Os 7.Sh NAME 8.Nm dummynet 9.Nd traffic shaper, bandwidth manager and delay emulator 10.Sh DESCRIPTION 11The 12.Nm 13system facility permits the control of traffic 14going through the various network interfaces, by applying bandwidth 15and queue size limitations, implementing different scheduling and queue 16management policies, and emulating delays and losses. 17.Pp 18The user interface for 19.Nm 20is implemented by the 21.Xr ipfw 8 22utility, so please refer to the 23.Xr ipfw 8 24manpage for a complete description of the 25.Nm 26capabilities and how to use it. 27.Ss Kernel Options 28The following options in the kernel configuration file are related to 29.Nm 30operation: 31.Pp 32.Bl -tag -width ".Dv IPFIREWALL_VERBOSE_LIMIT" -offset indent -compact 33.It Dv IPFIREWALL 34enable ipfirewall (required for 35.Nm ) 36.It Dv IPFIREWALL_VERBOSE 37enable firewall output 38.It Dv IPFIREWALL_VERBOSE_LIMIT 39limit firewall output 40.It Dv DUMMYNET 41enable 42.Nm 43operation 44.It Dv HZ 45set the timer granularity 46.El 47.Pp 48Generally, the following options are required: 49.Bd -literal -offset indent 50options IPFIREWALL 51options DUMMYNET 52options HZ=1000 # strongly recommended 53.Ed 54.Pp 55Additionally, one may want to increase the number 56of mbuf clusters (used to store network packets) according to the 57sum of the bandwidth-delay products and queue sizes of all configured 58pipes. 59.Sh SEE ALSO 60.Xr setsockopt 2 , 61.Xr if_bridge 4 , 62.Xr ip 4 , 63.Xr ipfw 8 , 64.Xr sysctl 8 65.Sh HISTORY 66The 67.Nm 68facility 69was initially implemented as a testing tool for 70.Tn TCP 71congestion control by 72.An Luigi Rizzo Aq luigi@iet.unipi.it , 73as described on ACM Computer Communication Review, Jan.97 issue. 74Later it has been modified to work at the 75.Tn IP 76and bridging levels, integrated with the 77.Xr ipfw 4 78packet filter, and extended to 79support multiple queueing and scheduling policies. 80