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.Dd January 26, 2021
.Dt ALTQ 4
.Os
.Sh NAME
.Nm ALTQ
.Nd "alternate queuing of network packets"
.Sh SYNOPSIS
.Cd options ALTQ
.Pp
.Cd options ALTQ_CBQ
.Cd options ALTQ_CODEL
.Cd options ALTQ_RED
.Cd options ALTQ_RIO
.Cd options ALTQ_HFSC
.Cd options ALTQ_CDNR
.Cd options ALTQ_PRIQ
.Cd options ALTQ_FAIRQ
.Sh DESCRIPTION
The
.Nm
system is a framework which provides several disciplines for queuing outgoing
network packets.
This is done by modifications to the interface packet queues.
See
.Xr altq 9
for details.
.Pp
The user interface for
.Nm
is implemented by the
.Xr pfctl 8
utility, so please refer to the
.Xr pfctl 8
and the
.Xr pf.conf 5
man pages for a complete description of the
.Nm
capabilities and how to use it.
.Ss Kernel Options
The following options in the kernel configuration file are related to
.Nm
operation:
.Pp
.Bl -tag -width ".Dv ALTQ_DEBUG" -compact
.It Dv ALTQ
Enable
.Nm .
.It Dv ALTQ_CBQ
Build the
.Dq "Class Based Queuing"
discipline.
.It Dv ALTQ_CODEL
Build the
.Dq "Controlled Delay"
discipline.
.It Dv ALTQ_RED
Build the
.Dq "Random Early Detection"
extension.
.It Dv ALTQ_RIO
Build
.Dq "Random Early Drop"
for input and output.
.It Dv ALTQ_HFSC
Build the
.Dq "Hierarchical Packet Scheduler"
discipline.
.It Dv 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.
.It Dv ALTQ_PRIQ
Build the
.Dq "Priority Queuing"
discipline.
.It Dv ALTQ_FAIRQ
Build the
.Dq "Fair Queuing"
discipline.
.It Dv ALTQ_NOPCC
Required if the TSC is unusable.
.It Dv ALTQ_DEBUG
Enable additional debugging facilities.
.El
.Pp
Note that
.Nm Ns -disciplines
cannot be loaded as kernel modules.
In order to use a certain discipline you have to build it into a custom
kernel.
The
.Xr pf 4
interface, that is required for the configuration process of
.Nm
can be loaded as a module.
.Sh SUPPORTED DEVICES
The driver modifications described in
.Xr altq 9
are required to use a certain network card with
.Nm .
They have been applied to the following hardware drivers:
.Xr ae 4 ,
.Xr age 4 ,
.Xr alc 4 ,
.Xr ale 4 ,
.Xr an 4 ,
.Xr aue 4 ,
.Xr axe 4 ,
.Xr bce 4 ,
.Xr bfe 4 ,
.Xr bge 4 ,
.Xr bxe 4 ,
.Xr cas 4 ,
.Xr cxgbe 4 ,
.Xr dc 4 ,
.Xr em 4 ,
.Xr epair 4 ,
.Xr et 4 ,
.Xr fxp 4 ,
.Xr gem 4 ,
.Xr igb 4 ,
.Xr ixgbe 4 ,
.Xr jme 4 ,
.Xr le 4 ,
.Xr liquidio 4 ,
.Xr msk 4 ,
.Xr mxge 4 ,
.Xr my 4 ,
.Xr nfe 4 ,
.Xr nge 4 ,
.Xr npe 4 ,
.Xr qlxgb 4 ,
.Xr re 4 ,
.Xr rl 4 ,
.Xr sge 4 ,
.Xr sis 4 ,
.Xr sk 4 ,
.Xr ste 4 ,
.Xr stge 4 ,
.Xr ti 4 ,
.Xr udav 4 ,
.Xr vge 4 ,
.Xr vr 4 ,
.Xr vte 4 ,
and
.Xr xl 4 .
.Pp
The
.Xr tun 4
and
.Xr ng_iface 4
pseudo drivers also do support
.Nm .
.Pp
The
.Xr vlan 4
driver does not directly support
.Nm ,
but as packets (mbufs) are passed to the underlying interface, a queue
can be defined for the underlying interface, and any packets directed
to the queue will be processed at the interface level.
An example:
.Pp
.Bd -literal -offset indent
altq on igb0 cbq queue { def aq }
queue def bandwidth 90% cbq (default borrow)
queue aq bandwidth 10Mb cbq
pass in on igb0.10 proto udp all queue aq keep state
.Ed
.Sh SEE ALSO
.Xr pf 4 ,
.Xr pf.conf 5 ,
.Xr ipfw 8 ,
.Xr pfctl 8 ,
.Xr altq 9
.Sh HISTORY
The
.Nm
system first appeared in March 1997 and found home in the KAME project
(http://www.kame.net).
It was imported to
.Fx
in 5.3 .
