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