Dynamips is a free open-source Cisco router hardware emulator, created by Christophe Fillot. Its main advantage compared to traditional router emulators is that it actually runs Cisco IOS. It accomplishes this task by emulating the hardware of the router, not the software. In 2005 when the project was first started, Dynamips only emulated the Cisco 7200 platform on a traditional PC. Now, it also supports Cisco 3600 series (3620, 3640 and 3660), 3700 series (3725, 3745) and 2600 series (2610 to 2650XM, 2691) and 1700 series routers.

By the authors own words, the goals of this emulator are mainly:

• To be used as a training platform, with software used in real world. It would allow people to become more familiar with Cisco devices, Cisco being the world leader in networking technologies;

• Test and experiment the numerous and powerful features of Cisco IOS;

• Check quickly configurations to be deployed later on real routers.

Of course, this emulator cannot replace a real router: you should be able to get a performance of about 1 kpps (depending on your host machine), to be compared to the 100 kpps delivered by a NPE-100 (the oldest NPE model). So, it is simply a complementary tool to real labs for administrators of Cisco networks or people wanting to pass their CCNA/CCNP/CCIE exams.

Dynamips is very easy to use but at the same time allows for some very large and also advanced hardware simulations. The only boundaries are the capabilities of your computer. On today’s typical computer, simulating 6 or 7 instances with 12.4T IOS is not a problem. It is even possible to distribute an emulated network across many computers, so actually there is no limitation in number of routers in the simulation.

At the time of this book being written, the Dynamips emulator is able to boot a large number of Cisco IOS releases available for the 7200, 3600, 3700, 2600 and 1700 platforms, including the latest 12.2S and 12.4T.

The project website is at http://www.ipflow.utc.fr/index.php/Cisco_7200_Simulator