65 lines
1.9 KiB
Groff
65 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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.Em dummynet
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is a system facility that 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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.Em dummynet
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is implemented by the
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.Nm ipfw
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program, so the reader is referred to the
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.Xr ipfw 8
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manpage for a complete description of the capabilities of
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.Nm
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and on how to use it.
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.Sh 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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.Bd -literal
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IPFIREWALL - enable ipfirewall (required for dummynet).
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IPFIREWALL_VERBOSE - enable firewall output.
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IPFIREWALL_VERBOSE_LIMIT - limit firewall output.
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DUMMYNET - enable dummynet operation.
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NMBCLUSTERS - set the amount of network packet buffers
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HZ - sets the timer granularity
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.Ed
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.Pp
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Generally, the following options are required:
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.Bd -literal
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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 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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.Nm
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was initially implemented as a testing tool for TCP congestion control
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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 then modified to work at the ip and bridging
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level, integrated with the IPFW packet filter, and extended to
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support multiple queueing and scheduling policies.
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