http://lartc.org/wondershaper/
http://www.bufferbloat.net/projects/cerowrt/wiki/Wondershape...
sudo wondershaper eth0 7500 850
sysctl -w net.core.default_qdisc=fq_codel
on as many machines as possible, and use something like OpenWRT's SQM instead of wondershaper on your router.
http://lartc.org/wondershaper/