[LARTC] SFQ

[Martin Krejcirik <mk@krej.cz>]

Hi,

could anybody enlighten me how SFQ is supposed to work, please ?

Consider this simple script:

tc qdisc add dev eth0 root handle 1: htb default 1 r2q 10 
tc class add dev eth0 parent 1:0 classid 1:1 htb rate 1Mbit ceil 1Mbit

tc qdisc add dev eth0 parent 1:1 sfq perturb 120
#tc qdisc add dev eth0 parent 1:1 pfifo limit 100

tc filter add dev eth0 parent 1:0 protocol ip prio 200 u32 \
   match ip dst 192.168.1.1 flowid 1:1

tc filter add dev eth0 parent 1:0 protocol ip prio 200 u32 \
   match ip dst 192.168.1.2 flowid 1:1


A single class limited to 1Mbit, sfq or pfifo attached to it and two 
filters.

I try to send some traffic from localhost to above two IPs, but I see 
absolutely no difference, whether I use sfq or pfifo qdisc. I thought 
when I send say 1.2Mbit UDP to 192.168.1.1, then ping to 192.168.1.2 
should be low (go through the other queue), but this is not happening.

Or when I send 5Mbit/s to one IP and then try ftp to the other, I get 
almost nothing through, I thought this was that was SFQ supposed to prevent ?

Could anybody describe some scenario, where I can see difference between 
sfq and fifo, please ?

thanks,
bye
__________________________________________________
Martin Krejcirik <mk@krej.cz>, PGP KeyID: B030351D



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