Translation to: Http://www.linuxjournal.com/content/non-linux-foss-virtualized-cisco-infrastructure
We're all familiar with the concept of virtual machines, and they're not just a great way to take advantage of server space resources, they also allow you to create and delete servers in an instant. It's perfect for a lab and training environment. Unfortunately, creating training experiments for Cisco hardware is always painful. Thanks to GNS3 (graphical Web simulator 3), this is no longer a problem.
Snapshot of the tool
GNS3 is an open source application used to create a virtual Cisco (or other hardware) architecture. Not only can you view traffic, you can also directly connect to the virtual appliance to configure them, just as you would configure the actual devices they represent. interface, it looks like a Visio diagram, but it's really a useful chart!
Whether you're actively trying to learn to use a Cisco device or just want to try out some network scenarios, GNS3 is an incredibly network-hardware sandbox tool. It does require you to provide iOS firmware (they do not provide the Cisco operating system themselves.) It runs under Windows,os X and Linux. If you are interested, you can download a copy in Http://www.gns3.net.