2 .\" $FreeBSD: src/share/man/man4/dummynet.4,v 1.4.2.12 2002/11/18 21:51:16 luigi Exp $
3 .\" $DragonFly: src/share/man/man4/dummynet.4,v 1.2 2003/06/17 04:36:59 dillon Exp $
10 .Nd traffic shaper, bandwidth manager and delay emulator
13 is a system facility that 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 program, so the reader is referred to the
24 manpage for a complete description of the capabilities of
28 The following options in the kernel configuration file are related to
32 IPFIREWALL - enable ipfirewall (required for dummynet).
33 IPFIREWALL_VERBOSE - enable firewall output.
34 IPFIREWALL_VERBOSE_LIMIT - limit firewall output.
35 DUMMYNET - enable dummynet operation.
36 NMBCLUSTERS - set the amount of network packet buffers
37 HZ - sets the timer granularity
40 Generally, the following options are required:
44 options HZ=1000 # strongly recommended
47 additionally, one may want to increase the number
48 of mbuf clusters (used to store network packets) according to the
49 sum of the bandwidth-delay products and queue sizes of all configured
59 was initially implemented as a testing tool for TCP congestion control
61 .An Luigi Rizzo Aq luigi@iet.unipi.it ,
62 as described on ACM Computer Communication Review, Jan.97 issue.
63 Later it has been then modified to work at the ip and bridging
64 level, integrated with the IPFW packet filter, and extended to
65 support multiple queueing and scheduling policies.