The DoS attacks they are bassically talkin about is just Icmp, ping -f and a ping of death, i mean come on all you have to do is limit the amount of packets that can simultaniously be transmited to you.
It takes processing power to drop packets too. This is why DOS/DDOS attacks are so hard to defend against. If it was as simple as "limiting the amount of packets" DOS attacks wouldn'
t be a problem.