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
34 enable ipfirewall (required for
36 .It Dv IPFIREWALL_VERBOSE
37 enable firewall output
38 .It Dv IPFIREWALL_VERBOSE_LIMIT
45 set the timer granularity
48 Generally, the following options are required:
49 .Bd -literal -offset indent
52 options HZ=1000 # strongly recommended
55 Additionally, one may want to increase the number
56 of mbuf clusters (used to store network packets) according to the
57 sum of the bandwidth-delay products and queue sizes of all configured
69 was initially implemented as a testing tool for
72 .An Luigi Rizzo Aq luigi@iet.unipi.it ,
73 as described on ACM Computer Communication Review, Jan.97 issue.
74 Later it has been modified to work at the
76 and bridging levels, integrated with the
78 packet filter, and extended to
79 support multiple queueing and scheduling policies.