GNS3 - Router emulator

GNS3 - Netwrok Router Emulator

1. Download GNS3 and Install it ... 

   main site : http://www.gns3.net
   forums : http://7200emu.hacki.at

2. Register those images before draw topology. 

   Cisco IOS for GNS3
   => http://gns3.blogspot.com.au/2007/10/ios.html