[LARTC] Best method for filtering ACKs?

[Stefan Gold]

Hello,

I'm wondering which of these filters is the best method for filtering ACK=20
packages to achieve lowest delay possible on a dsl-link.

This one ist from the wondershaper from the lartc-site:

/sbin/tc filter add dev $EXTIF parent 1:0 protocol ip prio 0 u32 \
=A0 match ip protocol 6 0xff \
=A0 match u8 0x05 0x0f at 0 \
=A0 match u16 0x0000 0xffc0 at 2 \
=A0 flowid 1:10

Thats a suggestion from the german computer magazine c't:

iptables -A POSTROUTING -t mangle -o $EXTIF -p tcp -m length --length :64 -=
j=20
MARK --set-mark 10
tc filter add dev $EXTIF parent 1:0 prio 0 protocol ip handle 10 fw flowid=
=20
1:10

But why so difficult? Is there a reason against filtering ACKs like this?

iptables -A POSTROUTING -t mangle -o $EXTIF -p tcp --tcp-flags ACK -j MARK=
=20
=2D-set-mark 10
tc filter add dev $EXTIF parent 1:0 prio 0 protocol ip handle 10 fw flowid=
=20
1:10

regards
Stefan