b6de9e91bd
replacement and has additional features which make it superior. Discussed on: -arch Reviewed by: thompsa X-MFC-after: never (RELENG_6 as transition period)
82 lines
1.9 KiB
Groff
82 lines
1.9 KiB
Groff
.\"
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.\" $FreeBSD$
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.\"
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.Dd October 28, 2002
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.Dt DUMMYNET 4
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.Os
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.Sh NAME
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.Nm dummynet
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.Nd traffic shaper, bandwidth manager and delay emulator
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.Sh DESCRIPTION
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The
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.Nm
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system facility permits the control of traffic
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going through the various network interfaces, by applying bandwidth
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and queue size limitations, implementing different scheduling and queue
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management policies, and emulating delays and losses.
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.Pp
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The user interface for
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.Nm
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is implemented by the
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.Xr ipfw 8
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utility, so please refer to the
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.Xr ipfw 8
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manpage for a complete description of the
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.Nm
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capabilities and how to use it.
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.Ss Kernel Options
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The following options in the kernel configuration file are related to
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.Nm
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operation:
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.Pp
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.Bl -tag -width ".Dv IPFIREWALL_VERBOSE_LIMIT" -offset indent -compact
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.It Dv IPFIREWALL
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enable ipfirewall (required for
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.Nm )
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.It Dv IPFIREWALL_VERBOSE
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enable firewall output
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.It Dv IPFIREWALL_VERBOSE_LIMIT
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limit firewall output
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.It Dv DUMMYNET
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enable
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.Nm
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operation
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.It Dv NMBCLUSTERS
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set the amount of network packet buffers
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.It Dv HZ
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set the timer granularity
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.El
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.Pp
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Generally, the following options are required:
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.Bd -literal -offset indent
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options IPFIREWALL
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options DUMMYNET
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options HZ=1000 # strongly recommended
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.Ed
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.Pp
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Additionally, one may want to increase the number
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of mbuf clusters (used to store network packets) according to the
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sum of the bandwidth-delay products and queue sizes of all configured
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pipes.
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.Sh SEE ALSO
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.Xr setsockopt 2 ,
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.Xr if_bridge 4 ,
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.Xr ip 4 ,
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.Xr ipfw 8 ,
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.Xr sysctl 8
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.Sh HISTORY
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The
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.Nm
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facility
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was initially implemented as a testing tool for
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.Tn TCP
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congestion control by
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.An Luigi Rizzo Aq luigi@iet.unipi.it ,
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as described on ACM Computer Communication Review, Jan.97 issue.
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Later it has been modified to work at the
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.Tn IP
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and bridging levels, integrated with the
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.Xr ipfw 4
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packet filter, and extended to
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support multiple queueing and scheduling policies.
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