9 .Nd traffic shaper, bandwidth manager and delay emulator
13 system facility permits the control of traffic
14 going through the various network interfaces, by applying bandwidth
15 and queue size limitations, implementing different scheduling and queue
16 management policies, and emulating delays and losses.
18 The user interface for
22 utility, so please refer to the
24 manpage for a complete description of the
26 capabilities and how to use it.
28 The following options in the kernel configuration file are related to
32 .Bl -tag -width ".Dv IPFIREWALL_VERBOSE_LIMIT" -offset indent -compact
36 is to be used with ipfw)
37 .It Dv IPFIREWALL_VERBOSE
38 enable firewall output
39 .It Dv IPFIREWALL_VERBOSE_LIMIT
46 set the timer granularity
49 Generally, the following options are required:
50 .Bd -literal -offset indent
53 options HZ=1000 # strongly recommended
56 Additionally, one may want to increase the number
57 of mbuf clusters (used to store network packets) according to the
58 sum of the bandwidth-delay products and queue sizes of all configured
72 was initially implemented as a testing tool for
75 .An Luigi Rizzo Aq Mt luigi@iet.unipi.it ,
76 as described on ACM Computer Communication Review, Jan.97 issue.
77 Later it has been modified to work at the
79 and bridging levels, integrated with the
81 packet filter, and extended to
82 support multiple queueing and scheduling policies.