bsd/man/man4/dummynet.4

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   4 .Dd October 28, 2002
   5 .Dt DUMMYNET 4
   6 .Os Darwin
   7 .Sh NAME
   8 .Nm dummynet
   9 .Nd traffic shaper, bandwidth manager and delay emulator
  10 .Sh DESCRIPTION
  11 .Em dummynet
  12 is a system facility that permits the control of traffic
  13 going through the various network interfaces, by applying bandwidth
  14 and queue size limitations, implementing different scheduling and queue
  15 management policies, and emulating delays and losses.
  16 .Pp
  17 The user interface for
  18 .Em dummynet
  19 is implemented by the
  20 .Nm ipfw
  21 program, so the reader is referred to the
  22 .Xr ipfw 8
  23 manpage for a complete description of the capabilities of
  24 .Nm
  25 and on how to use it.
  26 .Sh KERNEL OPTIONS
  27 The following options in the kernel configuration file are related to
  28 .Nm
  29 operation:
  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
  38 .Pp
  39 Generally, the following options are required:
  40 .Bd -literal
  41   options IPFIREWALL
  42   options DUMMYNET
  43   options HZ=1000       # strongly recommended
  44 .Ed
  45 .Pp
  46 additionally, one may want to increase the number
  47 of mbuf clusters (used to store network packets) according to the
  48 sum of the bandwidth-delay products and queue sizes of all configured
  49 pipes.
  50 .Sh SEE ALSO
  51 .Xr setsockopt 2 ,
  52 .Xr bridge 4 ,
  53 .Xr ip 4 ,
  54 .Xr ipfw 8 ,
  55 .Xr sysctl 8
  56 .Sh HISTORY
  57 .Nm
  58 was initially implemented as a testing tool for TCP congestion control
  59 by
  60 .An Luigi Rizzo Aq luigi@iet.unipi.it ,
  61 as described on ACM Computer Communication Review, Jan.97 issue.
  62 Later it has been then modified to work at the ip and bridging
  63 level, integrated with the IPFW packet filter, and extended to
  64 support multiple queueing and scheduling policies.