Re: PRIO qdisc traffic does not work as expected

[GGounot <g.gounot@laposte.net>]

Le 19/06/2014 12:33, Andy Furniss a écrit :
> GGounot wrote:
>> Hello,
>>
>> This is a simple case I started from lartc howto but I can't make it
>> work.
>>
>> The idea is : * 3 priorities * ftp.free.fr on prio 1 * 0.0.0.0/0 prio
>> 2 * ftp.lip6.fr prio 3
>>
>> Or, when Internet line is saturated and I download from ftp.free.fr,
>> my download should supersede all other downloads (my download should
>> take all bandwidth). On the other hand a download from ftp.lip6.fr
>> should occur only when there is some available bandwidth.
>>
>> But actually, when I download from ftp.free.fr and from ftp.lip6.fr
>> at the same time, both downloads have the same speed.
>>
>> This is the script : _________________ #!/bin/bash
>>
>> tc=/sbin/tc ETH=eth1 #connected to the LAN
>>
>> $tc qdisc del dev $ETH root 2>/dev/null $tc qdisc del dev $ETH
>> ingress 2>/dev/null
>>
>> ### PRIO ### # qdisc "prio", 3 levels $tc qdisc add dev $ETH root
>> handle 1: prio $tc qdisc add dev $ETH parent 1:1 handle 10: pfifo $tc
>> qdisc add dev $ETH parent 1:2 handle 20: pfifo $tc qdisc add dev $ETH
>> parent 1:3 handle 30: pfifo
>>
>> PRIO1="212.27.60.27" #ftp.free.fr PRIO2="0.0.0.0/0"
>> PRIO3="195.83.118.1" #ftp.lip6.fr # echo Prio 1 : $PRIO1 echo Prio 2
>> : $PRIO2 echo Prio 3 : $PRIO3
>>
>> $tc filter add dev $ETH parent 1:0 prio 1 protocol ip u32 match ip
>> src $PRIO1 flowid :1 $tc filter add dev $ETH parent 1:0 prio 3
>> protocol ip u32 match ip src $PRIO2 flowid :2 $tc filter add dev $ETH
>> parent 1:0 prio 2 protocol ip u32 match ip src $PRIO3 flowid :3
>> _________________
>>
>>
>> When I run : tc -s qdisc ls dev eth1 I see the 2 FIFOs showing
>> traffic going through. I don't understand what I am doing wrong, any
>> help will be appreciated.
>
> I don't understand your setup so 2 options.
>
> 1.
>
> You are only shaping the outgoing traffic, which isn't going to help
> with downloads incoming traffic. There isn't a perfect solution for
> shaping from the wrong end of a bottleneck, but you can sort of do it by
> using ifb and limiting the the rate to say 10-20% below the incoming
> bandwidth with htb/hfsc/etc.
>
> 2.
>
> Your shaping is actually seeing the download traffic leaving eth but not
> working because there is further buffering downstream after the prio so
> you would need to again use something where you can set the
> rates/overheads to make sure you are the bottleneck - this time you
> shouldn't need to sacrifice bandwidth.
>


Thanks for your answer.

The diagram is :
Internet <=> eth0 <=> eth1 <=> Client computer (which downloads using 
Firefox)

So shaping on eth1 outgoing traffic should limit the rate Client 
receives data from Internet.

Would shaping on eth0 using :
  tc qdisc add dev eth0handle ffff: ingress
  ifconfig ifb0 up
  tc filter add dev eth0 parent ffff: protocol all u32 match u32 0 0 
action mirred egress redirect dev ifb0
and run the script on ifb0 be a better solution ?


Other way :
eth0 has a public IP (is directly connected to Internet).

eth0 and eth1 are 100Mb/s network PCI cards.

The Internet link has a rate of ~4000Kb/s.

Is the use of PRIO qdisc the problem ? (since it (maybe) acts on the 
network card rate, not the actual Internet connection rate)