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2.\" $FreeBSD: head/share/man/man4/dummynet.4 106073 2002-10-28 07:24:58Z luigi $
2.\" $FreeBSD: head/share/man/man4/dummynet.4 107383 2002-11-29 11:39:20Z ru $
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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
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
18.Em dummynet
19.Nm
20is implemented by the
20.Nm ipfw
21program, so the reader is referred to the
21.Xr ipfw 8
23manpage for a complete description of the capabilities of
22utility, so please refer to the
23.Xr ipfw 8
24manpage for a complete description of the
25.Nm
25and on how to use it.
26.Sh KERNEL OPTIONS
26capabilities and how to use it.
27.Ss Kernel Options
28The following options in the kernel configuration file are related to
29.Nm
30operation:
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 HZ - sets the timer granularity
37.Ed
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:
40.Bd -literal
41 options IPFIREWALL
42 options DUMMYNET
43 options HZ=1000 # strongly recommended
51.Bd -literal -offset indent
52options IPFIREWALL
53options DUMMYNET
54options HZ=1000 # strongly recommended
55.Ed
56.Pp
46additionally, one may want to increase the number
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 bridge 4 ,
64.Xr ip 4 ,
65.Xr ipfw 8 ,
66.Xr sysctl 8
67.Sh HISTORY
68The
69.Nm
58was initially implemented as a testing tool for TCP congestion control
59by
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.
62Later it has been then modified to work at the ip and bridging
63level, integrated with the IPFW packet filter, and extended to
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.