Disclosed herein are methods and apparatus for discovering devices on a network. Active devices can be discovered in ARP tables from routers on the network. Pings can then be sent to the active devices for verification, or pings can be sent to devices at other addresses on the network....http://www.google.co.uk/patents/US5835720?utm_source=gb-gplus-sharePatent US5835720 - IP discovery apparatus and method
