There have been whispers about Cisco releasing their own emulation platform for some time now. Something like Dynamips/GNS3 but the IOS included.
Cisco have now released VIRL to the public. VIRL stands for Virtual Internet Routing Lab and it runs off a virtual machine. It's big news for any Cisco student who wants to get their hands on equipment but it also scales to very large networks allowing you to create large networks. It can run:
You can add third party virtual machines and servers and connect to live networks. Using the GUI it can actually build complex configurations for you allowing you to test the entire infrastructure before deployment. You can simply paste the configurations into your live equipment when you are ready!
The downloadable images are available for either VMware Fusion/Desktop or VMware ESXi.
It's a yearly subscription of $79-199 depending on the version you get but you have to compare this to costs of live rack rental, headaches with GNS3 etc. If you use the coupon code VIRL50 you get 50% off the annual personal edition. This isn't my coupon, it's open to anyone to use.
But before you get too excited, there seems to be no support at the moment for layer 2 switching so you will be There are no ASIC simulations and since all the cool L2 stuff is done in ASICs, there are no L2 features at the moment leaving out all your VLAN, trunking, switch port security etc. Bummer. You would still need to use Packet Tracer or a live CCNA/CCNP rack such as ours at – http://www.howtonetwork.com/live-cisco-racks/.
Here is the link to the VIRL website. I haven't used it myself and I'm not sure I will until they can offer L2 switch support.