xenial (5) fireqos-quantum.5.gz
NAME
fireqos-params-class - optional class parameters
SYNOPSIS
rate | commit | min speed
ceil | max speed
minrate speed
{ qdisc qdisc-name | pfifo|bfifo|sfq|fq_codel|codel|none } [options "qdisc-options"]
prio { 0..7 | keep | last }
{ linklayer linklayer-name } | { adsl {local|remote} encapsulation } | ethernet | atm
mtu bytes
mpu bytes
tsize size
overhead bytes
r2q factor
burst bytes
cburst bytes
quantum bytes
priority | balanced
DESCRIPTION
All of the options apply to interface and class statements.
Units for speeds are defined in fireqos.conf(5).
rate, commit, min
When a committed rate of speed is provided to a class, it means that the bandwidth will be given to the
class when it needs it. If the class does not need the bandwidth, it will be available for any other
class to use.
For interfaces, a rate must be defined.
For classes the rate defaults to 1/100 of the interface capacity.
ceil, max
Defines the maximum speed a class can use. Even there is available bandwidth, a class will not exceed
its ceil speed.
For interfaces, the default is the rate speed of the interface.
For classes, the defaults is the ceil of the their interfaces.
minrate
Defines the default committed speed for all classes not specifically given a rate in the config file. It
forces a recalculation of tc(8) r2q.
When minrate is not given, FireQOS assigns a default value of 1/100 of the interface rate.
qdisc qdisc-name, pfifo, bfifo, sfq, fq_codel, codel, none
The qdisc defines the method to distribute class bandwidth to its sockets. It is applied within the
class itself and is useful in cases where a class gets saturated. For information about these, see the
Traffic Control Howto (http://www.tldp.org/HOWTO/Traffic-Control-HOWTO/classless-qdiscs.html)
A qdisc is only useful when applied to a class. It can be specified at the interface level in order to
set the default for all of the included classes.
To pass options to a qdisc, you can specify them through an environment variable or explicitly on each
class.
Set the variable FIREQOS_DEFAULT_QDISC_OPTIONS_qdiscname in the config file. For example, for sfq:
FIREQOS_DEFAULT_QDISC_OPTIONS_sfq="perturb 10 quantum 2000".
Using this variable each sfq will get these options by default. You can still override this by
specifying explicit options for individual qdiscs, for example to add some sfq options you would write:
class classname sfq options "perturb 10 quantum 2000"
The options keyword must appear just after the qdisc name.
prio (class)
Note
There is also a match parameter called prio, see fireqos-params-match(5).
HTB supports 8 priorities, from 0 to 7. Any number less than 0 will give priority 0. Any number above 7
will give priority 7.
By default, FireQOS gives the first class priority 0, and increases this number by 1 for each class it
encounters in the config file. If there are more than 8 classes, all classes after the 8th will get
priority 7. In balanced mode (see balanced, below), all classes will get priority 4 by default.
FireQOS restarts priorities for each interface and class group.
The class priority defines how the spare bandwidth is spread among the classes. Classes with higher
priorities (lower prio) will get all spare bandwidth. Classes with the same priority will get a
percentage of the spare bandwidth, proportional to their committed rates.
The keywords keep and last will make a class use the priority of the class just above / before it. So to
make two consecutive classes have the same prio, just add prio keep to the second one.
linklayer linklayer-name, ethernet, atm
The linklayer can only be given on interfaces. It is used by the kernel to calculate the overheads in
the packets.
adsl
adsl is a special linklayer that automatically calculates ATM overheads for the link.
local is used when the ADSL modem is directly attached to your computer (for example a PCI card, or a USB
modem).
remote is used when you have an ADSL router attached to an ethernet port of your computer.
When one is using PPPoE pass-through, so there is an ethernet ADSL modem (not router) and PPP is running
on the Linux host, the option to choose is local.
Note
This special case has not yet been demonstrated for sure. Experiment a bit and if you find out,
let us know to update this page. In practice, this parameter lets the kernel know that the
packets it sees, have already an ethernet header on them.
encapsulation can be one of (all the labels on the same line are aliases):
• IPoA-VC/Mux or ipoa-vcmux or ipoa-vc or ipoa-mux,
• IPoA-LLC/SNAP or ipoa-llcsnap or ipoa-llc or ipoa-snap
• Bridged-VC/Mux or bridged-vcmux or bridged-vc or bridged-mux
• Bridged-LLC/SNAP or bridged-llcsnap or bridged-llc or bridged-snap
• PPPoA-VC/Mux or pppoa-vcmux or pppoa-vc or pppoa-mux
• PPPoA-LLC/SNAP or pppoa-llcsnap or pppoa-llc or pppoa-snap
• PPPoE-VC/Mux or pppoe-vcmux or pppoe-vc or pppoe-mux
• PPPoE-LLC/SNAP or pppoe-llcsnap or pppoe-llc or pppoe-snap
If your adsl router can give you the mtu, it would be nice to add an mtu parameter too. For detailed
info, see here (http://ace-host.stuart.id.au/russell/files/tc/tc-atm/).
mtu
Defines the MTU of the interface in bytes.
FireQOS will query the interface to find its MTU. You can overwrite this behaviour by giving this
parameter to a class or interface.
mpu
Defines the MPU of the interface in bytes.
FireQOS does not set a default value. You can set your own using this parameter.
tsize
FireQOS does not set a default size. You can set your own using this parameter.
overhead
FireQOS automatically calculates the bytes overhead for ADSL. For all other technologies, you can
specify the overhead in the config file.
r2q
FireQOS calculates the proper r2q factor, so that you can control speeds in steps of 1/100th of the
interface speed (if that is possible).
Note
The HTB manual states that this parameter is ignored when a quantum have been set. By default,
FireQOS sets quantum to interface MTU, so r2q is probably is ignored by the kernel.
burst
burst specifies the number of bytes that will be sent at once, at ceiling speed, when a class is allowed
to send traffic. It is like a 'traffic unit'. A class is allowed to send at least burst bytes before
trying to serve any other class.
burst should never be lower that the interface mtu and class groups and interfaces should never have a
smaller burst value than their children. If you do specify a higher burst for a child class, its parent
may get stuck sometimes (the child will drain the parent).
By default, FireQOS lets the kernel decide this parameter, which calculates the lowest possible value
(the minimum value depends on the rate of the interface and the clock speed of the CPU).
burst is inherited from interfaces to classes and from group classes to their subclasses. FireQOS will
not allow you to set a burst at a subclass, higher than its parent. Setting a burst of a subclass higher
than its parent will drain the parent class, which may be stuck for up to a minute when this happens.
For this check to work, FireQOS uses just its configuration (it does not query the kernel to check how
the value specified in the config file for a subclass relates to the actual value of its parent).
cburst
cburst is like burst, but at hardware speed (not just ceiling speed).
By default, FireQOS lets the kernel decide this parameter.
cburst is inherited from interfaces to classes and from group classes to their subclasses. FireQOS will
not allow you to set a cburst at a subclass, higher to its parent. Setting a cburst of a subclass higher
than its parent, will drain the parent class, which may be stuck for up to a minute when this happens.
For this check to work, FireQOS uses just its configuration (it does not query the kernel to check how
the value specified in the config file for a subclass relates to the actual value of its parent).
quantum
quantum specifies the number of bytes a class is allowed to send at once, when it is borrowing spare
bandwidth from other classes.
By default, FireQOS sets quantum to the interface mtu.
quantum is inherited from interfaces to classes and from group classes to their subclasses.
priority, balanced
These parameters set the priority mode of the child classes.
priority
priority is the default mode, where FireQOS assigns an incremental priority to each class. In
this mode, the first class takes prio 0, the second prio 1, etc. When a class has a higher prio
than the others (higher = smaller number), this high priority class will get all the spare
bandwidth available, when it needs it. Spare bandwidth will be allocate to lower priority classes
only when the higher priority ones do not need it.
balanced
balanced mode gives prio 4 to all child classes. When multiple classes have the same prio, the
spare bandwidth available is spread among them, proportionally to their committed rate. The value
4 can be overwritten by setting FIREQOS_BALANCED_PRIO at the top of the config file to the prio
you want the balanced mode to assign for all classes.
The priority mode can be set in interfaces and class groups. The effect is the same. The classes that
are defined as child classes, will get by default the calculated class prio based on the priority mode
given.
These options affect only the default prio that will be assigned by FireQOS. The default is used only if
you don't explicitly use a prio parameter on a class.
Note
There is also a match parameter called priority, see fireqos-params-match(5).
SEE ALSO
• fireqos(1) - FireQOS program • fireqos.conf(5) - FireQOS configuration file • fireqos-interface(5) - QOS interface definition • fireqos-class(5) - QOS class definition • FireHOL Website (http://firehol.org/) • FireHOL Online PDF Manual (http://firehol.org/firehol-manual.pdf) • FireHOL Online HTML Manual (http://firehol.org/manual)
AUTHORS
FireHOL Team.