If you are currently working on CCIE lab prepararion and have equipment issues - there is good news that there's a good Router simulation tool out there. It is able to boot a large number of Cisco IOS releases available for the 7200 and 3600 platforms, including the latest 12.2S and 12.4T:
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I've also found a good article on how to use "DYNAMIPS" for the NetMasterClass DOiT Workbook:
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Also: Basic Windows XP Dynamips/Dynagen Installation and Troubleshooting steps
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If you do not know what DOiT is:
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Hope it would help :-)Ivan