2006-10-26 memo http://www.hitachi-system.co.jp/packetshaper/function/gijyutsu.html http://www.mrl.co.jp/system/ip_infrastructure/mr-optts.htm http://www.linux.or.jp/JF/JFdocs/Adv-Routing-HOWTO/lartc.cookbook.icmp-ratelimit.html http://netvolante.jp/solution/cost/softbank2004_02.html