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 NMBCLUSTERS 45set the amount of network packet buffers 46.It Dv HZ 47set the timer granularity 48.El 49.Pp 50Generally, the following options are required: 51.Bd -literal -offset indent 52options IPFIREWALL 53options DUMMYNET 54options HZ=1000 # strongly recommended 55.Ed 56.Pp 57Additionally, one may want to increase the number 58of mbuf clusters (used to store network packets) according to the 59sum of the bandwidth-delay products and queue sizes of all configured 60pipes. 61.Sh SEE ALSO 62.Xr setsockopt 2 , 63.Xr if_bridge 4 , 64.Xr ip 4 , 65.Xr ipfw 8 , 66.Xr sysctl 8 67.Sh HISTORY 68The 69.Nm 70facility 71was initially implemented as a testing tool for 72.Tn TCP 73congestion control by 74.An Luigi Rizzo Aq luigi@iet.unipi.it , 75as described on ACM Computer Communication Review, Jan.97 issue. 76Later it has been modified to work at the 77.Tn IP 78and bridging levels, integrated with the 79.Xr ipfw 4 80packet filter, and extended to 81support multiple queueing and scheduling policies. 82