GNS3 is a graphical network simulator that allows simulation of
complex networks.
To allow complete simulations, GNS3 is strongly linked with:
  * Dynamips, the core program that allows Cisco IOS emulation.
  * Dynagen, a text-based front-end for Dynamips.
  * Pemu, a Cisco PIX firewall emulator based on Qemu.

GNS3 is an excellent complementary tool to real labs for Cisco
network engineers, administrators and people wanting to pass
certifications such as CCNA, CCNP, CCIP or CCIE.  It can also
be used to experiment features of Cisco IOS or to check
configurations that need to be deployed later on real routers.

Features overview
  * Design of high quality and complex network topologies.
  * Emulation of many Cisco router platforms and PIX firewalls.
  * Simulation of simple Ethernet, ATM and Frame Relay switches.
  * Connection of the simulated network to the real world!
  * Packet capture using Wireshark.

Important notice: users have to provide their own Cisco IOS
to use with GNS3. It is also recommended to read the
documentation _before_ starting the program.
