DynaMIPs site: http://dyna-gen.sourceforge.net/ blog: http://www.ipflow.utc.fr/blog/ forum: http://hacki.at/7200emu/ DynaGEN http://dynagen.org/ http://www.internetworkexpert.com/resources/iosonpc.htm The cheapest alternative is using emulation for the routers in your lab. For this, take a look at Dynamips. I’m not going to go into too much detail, but it can do every thing that the above routers can do and much more! It can be used for certification well beyond the CCNA level. On the downside, it takes a lot of playing with it to finally get it working correctly (the learning curve is well worth it). Check out their blog, site and forum for all the good info—you won’t be sorry, trust me. This isn’t your typical emulator like Boson (I generally don’t recommend router simulators similar to these), Dynamips uses real IOS images for emulation. So, this means you will most likely need a service contract in order to have access to the IOS images. Crossover cables are also called "back to back" or "back-to-back" cables...