GNS3 is a graphical network simulator that allows you to design complex network topologies and to launch simulations on them.

To allow complete simulations, GNS3 is strongly linked with :

  • Dynamips, an IOS emulator which allows users to run IOS binary images from Cisco Systems.
  • Dynagen, a text-based front-end for Dynamips.

GNS3 is an open source product that may be used on multiple platforms, including Windows, Linux, and MacOS X.