1.\" 2.\" $FreeBSD: src/share/man/man4/dummynet.4,v 1.4.2.12 2002/11/18 21:51:16 luigi Exp $ 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 11.Em dummynet 12is a system facility that permits the control of traffic 13going through the various network interfaces, by applying bandwidth 14and queue size limitations, implementing different scheduling and queue 15management policies, and emulating delays and losses. 16.Pp 17The user interface for 18.Em dummynet 19is implemented by the 20.Nm ipfw 21program, so the reader is referred to the 22.Xr ipfw 8 23manpage for a complete description of the capabilities of 24.Nm 25and on how to use it. 26.Sh KERNEL OPTIONS 27The following options in the kernel configuration file are related to 28.Nm 29operation: 30.Bd -literal 31 IPFIREWALL - enable ipfirewall (required for dummynet). 32 IPFIREWALL_VERBOSE - enable firewall output. 33 IPFIREWALL_VERBOSE_LIMIT - limit firewall output. 34 DUMMYNET - enable dummynet operation. 35 NMBCLUSTERS - set the amount of network packet buffers 36.Ed 37.Pp 38Generally, the following options are required: 39.Bd -literal 40 options IPFIREWALL 41 options DUMMYNET 42.Ed 43.Pp 44additionally, one may want to increase the number 45of mbuf clusters (used to store network packets) according to the 46sum of the bandwidth-delay products and queue sizes of all configured 47pipes. 48Timer granularity is controlled by 49.Xr sysctl 8 50variable 51.Va net.inet.ip.dummynet.hz , 52which is set to 1000 by default. 53.Sh SEE ALSO 54.Xr setsockopt 2 , 55.Xr bridge 4 , 56.Xr ip 4 , 57.Xr ipfw 8 , 58.Xr sysctl 8 59.Sh HISTORY 60.Nm 61was initially implemented as a testing tool for TCP congestion control 62by 63.An Luigi Rizzo Aq Mt luigi@iet.unipi.it , 64as described on ACM Computer Communication Review, Jan.97 issue. 65Later it has been then modified to work at the ip and bridging 66level, integrated with the IPFW packet filter, and extended to 67support multiple queueing and scheduling policies. 68