table of contents
|DUMMYNET(4)||Device Drivers Manual||DUMMYNET(4)|
dummynet — traffic
shaper, bandwidth manager and delay emulator
dummynet 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
dummynet capabilities and how to use it.
The following options in the kernel configuration file are related
- enable ipfirewall (required for
- enable firewall output
- limit firewall output
- set the timer granularity
Generally, the following options are required:
options IPFIREWALL options DUMMYNET 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.
dummynet facility was initially
implemented as a testing tool for TCP congestion control by
Luigi Rizzo <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 policies.
|October 28, 2002||Debian|