NAME

ALTQ — alternate queuing of network packets

SYNOPSIS

options ALTQ

options ALTQ_CBQ
options ALTQ_CODEL
options ALTQ_RED
options ALTQ_RIO
options ALTQ_HFSC
options ALTQ_CDNR
options ALTQ_PRIQ
options ALTQ_FAIRQ

DESCRIPTION

The ALTQ system is a framework which provides several disciplines for queuing outgoing network packets. This is done by modifications to the interface packet queues. See altq(9) for details.
The user interface for ALTQ is implemented by the pfctl(8) utility, so please refer to the pfctl(8) and the pf.conf(5) man pages for a complete description of the ALTQ capabilities and how to use it.

Kernel Options

The following options in the kernel configuration file are related to ALTQ operation:
ALTQ
Enable ALTQ.
ALTQ_CBQ
Build the “Class Based Queuing” discipline.
ALTQ_CODEL
Build the “Controlled Delay” discipline.
ALTQ_RED
Build the “Random Early Detection” extension.
ALTQ_RIO
Build “Random Early Drop” for input and output.
ALTQ_HFSC
Build the “Hierarchical Packet Scheduler” discipline.
ALTQ_CDNR
Build the traffic conditioner. This option is meaningless at the moment as the conditioner is not used by any of the available disciplines or consumers.
ALTQ_PRIQ
Build the “Priority Queuing” discipline.
ALTQ_FAIRQ
Build the “Fair Queuing” discipline.
ALTQ_NOPCC
Required if the TSC is unusable.
ALTQ_DEBUG
Enable additional debugging facilities.
Note that ALTQ-disciplines cannot be loaded as kernel modules. In order to use a certain discipline you have to build it into a custom kernel. The pf(4) interface, that is required for the configuration process of ALTQ can be loaded as a module.

SUPPORTED DEVICES

The driver modifications described in altq(9) are required to use a certain network card with ALTQ. They have been applied to the following hardware drivers: ae(4), age(4), alc(4), ale(4), an(4), aue(4), axe(4), bce(4), bfe(4), bge(4), bxe(4), cas(4), cxgbe(4), dc(4), de(4), ed(4), em(4), ep(4), epair(4), et(4), fxp(4), gem(4), hme(4), igb(4), ixgbe(4), jme(4), le(4), liquidio(4), msk(4), mxge(4), my(4), nfe(4), nge(4), npe(4), qlxgb(4), re(4), rl(4), sf(4), sge(4), sis(4), sk(4), ste(4), stge(4), ti(4), txp(4), udav(4), vge(4), vr(4), vte(4), and xl(4).
The ndis(4) framework also has support for ALTQ and thus all encapsulated drivers.
The tun(4) and ng_iface(4) pseudo drivers also do support ALTQ.

SEE ALSO

pf(4), pf.conf(5), ipfw(8), pfctl(8), altq(9)

HISTORY

The ALTQ system first appeared in March 1997 and found home in the KAME project (http://www.kame.net). It was imported to FreeBSD in 5.3 .