|
Packit Service |
3880ab |
.TH PFIFO_FAST 8 "10 January 2002" "iproute2" "Linux"
|
|
Packit Service |
3880ab |
.SH NAME
|
|
Packit Service |
3880ab |
pfifo_fast \- three-band first in, first out queue
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
.SH DESCRIPTION
|
|
Packit Service |
3880ab |
pfifo_fast is the default qdisc of each interface.
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
Whenever an interface is created, the pfifo_fast qdisc is automatically used
|
|
Packit Service |
3880ab |
as a queue. If another qdisc is attached, it preempts the default
|
|
Packit Service |
3880ab |
pfifo_fast, which automatically returns to function when an existing qdisc
|
|
Packit Service |
3880ab |
is detached.
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
In this sense this qdisc is magic, and unlike other qdiscs.
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
.SH ALGORITHM
|
|
Packit Service |
3880ab |
The algorithm is very similar to that of the classful
|
|
Packit Service |
3880ab |
.BR tc-prio (8)
|
|
Packit Service |
3880ab |
qdisc.
|
|
Packit Service |
3880ab |
.B pfifo_fast
|
|
Packit Service |
3880ab |
is like three
|
|
Packit Service |
3880ab |
.BR tc-pfifo (8)
|
|
Packit Service |
3880ab |
queues side by side, where packets can be enqueued in any of the three bands
|
|
Packit Service |
3880ab |
based on their Type of Service bits or assigned priority.
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
Not all three bands are dequeued simultaneously - as long as lower bands
|
|
Packit Service |
3880ab |
have traffic, higher bands are never dequeued. This can be used to
|
|
Packit Service |
3880ab |
prioritize interactive traffic or penalize 'lowest cost' traffic.
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
Each band can be txqueuelen packets long, as configured with
|
|
Packit Service |
3880ab |
.BR ifconfig (8)
|
|
Packit Service |
3880ab |
or
|
|
Packit Service |
3880ab |
.BR ip (8).
|
|
Packit Service |
3880ab |
Additional packets coming in are not enqueued but are instead dropped.
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
See
|
|
Packit Service |
3880ab |
.BR tc-prio (8)
|
|
Packit Service |
3880ab |
for complete details on how TOS bits are translated into bands.
|
|
Packit Service |
3880ab |
.SH PARAMETERS
|
|
Packit Service |
3880ab |
.TP
|
|
Packit Service |
3880ab |
txqueuelen
|
|
Packit Service |
3880ab |
The length of the three bands depends on the interface txqueuelen, as
|
|
Packit Service |
3880ab |
specified with
|
|
Packit Service |
3880ab |
.BR ifconfig (8)
|
|
Packit Service |
3880ab |
or
|
|
Packit Service |
3880ab |
.BR ip (8).
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
.SH BUGS
|
|
Packit Service |
3880ab |
Does not maintain statistics and does not show up in tc qdisc ls. This is because
|
|
Packit Service |
3880ab |
it is the automatic default in the absence of a configured qdisc.
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
.SH SEE ALSO
|
|
Packit Service |
3880ab |
.BR tc (8)
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
.SH AUTHORS
|
|
Packit Service |
3880ab |
Alexey N. Kuznetsov, <kuznet@ms2.inr.ac.ru>
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
This manpage maintained by bert hubert <ahu@ds9a.nl>
|