1.\" 2.\" $FreeBSD: src/share/man/man4/dummynet.4,v 1.4.2.12 2002/11/18 21:51:16 luigi Exp $ 3.\" $DragonFly: src/share/man/man4/dummynet.4,v 1.3 2007/10/16 11:28:40 sephe Exp $ 4.\" 5.Dd October 28, 2002 6.Dt DUMMYNET 4 7.Os 8.Sh NAME 9.Nm dummynet 10.Nd traffic shaper, bandwidth manager and delay emulator 11.Sh DESCRIPTION 12.Em dummynet 13is a system facility that 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.Em dummynet 20is implemented by the 21.Nm ipfw 22program, so the reader is referred to the 23.Xr ipfw 8 24manpage for a complete description of the capabilities of 25.Nm 26and on how to use it. 27.Sh KERNEL OPTIONS 28The following options in the kernel configuration file are related to 29.Nm 30operation: 31.Bd -literal 32 IPFIREWALL - enable ipfirewall (required for dummynet). 33 IPFIREWALL_VERBOSE - enable firewall output. 34 IPFIREWALL_VERBOSE_LIMIT - limit firewall output. 35 DUMMYNET - enable dummynet operation. 36 NMBCLUSTERS - set the amount of network packet buffers 37.Ed 38.Pp 39Generally, the following options are required: 40.Bd -literal 41 options IPFIREWALL 42 options DUMMYNET 43.Ed 44.Pp 45additionally, one may want to increase the number 46of mbuf clusters (used to store network packets) according to the 47sum of the bandwidth-delay products and queue sizes of all configured 48pipes. 49Timer granularity is controlled by 50.Xr sysctl 8 51variable 52.Va net.inet.ip.dummynet.hz , 53which is set to 1000 by default. 54.Sh SEE ALSO 55.Xr setsockopt 2 , 56.Xr bridge 4 , 57.Xr ip 4 , 58.Xr ipfw 8 , 59.Xr sysctl 8 60.Sh HISTORY 61.Nm 62was initially implemented as a testing tool for TCP congestion control 63by 64.An Luigi Rizzo Aq luigi@iet.unipi.it , 65as described on ACM Computer Communication Review, Jan.97 issue. 66Later it has been then modified to work at the ip and bridging 67level, integrated with the IPFW packet filter, and extended to 68support multiple queueing and scheduling policies. 69