traffic shaper, bandwidth manager and delay
system facility permits the
control of traffic going through the various network interfaces, by applying
bandwidth and queue size limitations, implementing different scheduling and
queue management policies, and emulating delays and losses.
The user interface for
implemented by the ipfw(8)
utility, so please
refer to the ipfw(8)
manpage for a complete
description of the
and how to use it.
The following options in the kernel configuration file are related to
Generally, the following options are required:
options HZ=1000 # strongly recommended
Additionally, one may want to increase the number of mbuf clusters (used to
store network packets) according to the sum of the bandwidth-delay products
and queue sizes of all configured pipes.
facility was initially
implemented as a testing tool for TCP congestion control by
⟨firstname.lastname@example.org⟩, as described on ACM Computer Communication
Review, Jan.97 issue. Later it has been modified to work at the IP and
bridging levels, integrated with the ipfw(4)
packet filter, and extended to support multiple queueing and scheduling