http://www.iana.org/ipaddress/ip-addresses.htm
http://www.freesoft.org/CIE/Topics/26.htm
http://www.isoc.org/briefings/021/
http://www.cisco.com/en/US/products/ps6350/products_configuration_guide_chapter09186a00800ca7c0.html
http://www.cisco.com/en/US/products/sw/secursw/ps1018/products_tech_note09186a00800a5b9a.shtml
http://www.cisco.com/en/US/tech/tk827/tk369/technologies_white_paper09186a00800949b8.shtml
http://www.cisco.com/en/US/tech/tk583/tk822/technologies_tech_note09186a0080094524.shtml
http://www.cisco.com/en/US/products/sw/iosswrel/ps1834/products_feature_guide09186a0080080374.html
http://www.cisco.com/en/US/tech/tk648/tk361/technologies_white_paper09186a00801a1a55.shtml
http://www.cisco.com/en/US/products/ps6350/products_configuration_guide_chapter09186a0080431056.html
http://www.cisco.com/en/US/tech/tk648/tk361/technologies_white_paper09186a00801afc76.shtml