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sw:opnsense:traffic_shaper [2019/03/25 14:24] – created niziaksw:opnsense:traffic_shaper [2020/05/13 09:33] (current) – niziak
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 +====== Traffic Shaper ======
 +
 [[https://www.freebsd.org/cgi/man.cgi?query=dummynet&apropos=0&sektion=0&manpath=FreeBSD+11.2-RELEASE&arch=default&format=html|dummynet]] -- flexible bandwidth manager and delay emulator [[https://www.freebsd.org/cgi/man.cgi?query=dummynet&apropos=0&sektion=0&manpath=FreeBSD+11.2-RELEASE&arch=default&format=html|dummynet]] -- flexible bandwidth manager and delay emulator
 +[[http://caia.swin.edu.au/reports/160708A/CAIA-TR-160708A.pdf]]
 +
 +Some terms:
 +
 +  * **AQM** - **A**ctive **Q**ueue **M**anagement
 +    * **droptail** - drop packetss if full
 +    * **CoDel**
 +    * **PIE**
 +
 +  * **pipe** (link, limiter)- virtual path that emulates a connection with a specified bandwidth, propagation delay, and packet loss pattern. 
 +  * **scheduler** - arbitrate access of multiple flows to the same link (pipe)
 +    * FIFO
 +    * DRR
 +    * PRIO
 +    * WF2Q+
 +    * QFQ
 +    * KPS
 +
 +
 +  * Simple pipe internally has attached
 +      * queue (droptail)
 +      * scheduler (FIFO)
 +      * pipe (a link emulator with given badwidth and delay)
 +{{:sw:opnsense:fig5_a_simple_dummynet_pipe.jpg?400|}}
 +
 +===== FQ-CoDel =====
 +The **FlowQueue-CoDel** (**FQ-CoDel**) algorithm is a combined packet scheduler and Active Queue Management (AQM) algorithm.
 +
 +  * Pipe with fq-CoDel AQM set
 +      * queue is a dummy queue without any management policy (no droptail). It is not used to buffer incoming packets
 +      * fq-CoDel scheduler manages internal queues to buffer packets
 +{{:sw:opnsense:fig7_fq_codel.jpg?400|}}
 +
 +
 +REMARKS:
 +  * **fq-CoDel** on queues is ignored when **fq-codel** is enabled on pipe.
 +    * queue is needed (even if not really used). There is no other way to send packets to **fq-codel** scheduler. So creating a pipe with **fq-codel** will always create a queue.
 +  * number of internal queues in **fq-codel** is condifured by **flows** parameter
 +
 +
  
 +===== shell =====
  
-  * pipe - virtual path that emulates a connection with a specified bandwidth, propagation delay, and packet loss pattern. +<code bash> 
-  * pipe has also internal queue of waiting packets. If there is no space in queue, pipe starts dropping packets +ipfw pipe show 
-  * queue - buffer of object to enforce WFQ2+ queuing strategy.+ipfw sched show 
 +ipfw queue show 
 +</code>