Good article with introductory discussion: http://www.techrepublic.com/blog/networking/practice-cisco-router-configuration-using-a-free-emulator/419 Supported Hardware Dynagen/Dynamips: Cisco 7200, Cisco 3600 series (3620, 3640 and 3660), 3700 series (3725, 3745) and 2600 series (2610 to 2650XM, 2691). Emulators/Simulators Dynagen/Dynamips (excellent choice and good for windows and *nix): http://www.gns3.net/download… Continue reading