+ 0 Votes Find the best IOS JohnBHeller 4 years ago Hi, I have found the cisco IOS selector to be very useful in finding features i need. http://tools.cisco.com/ITDIT/ISTMAIN/Dispatch?act=rlsSelect&task=search It allows you to see long list of possible IOS versions to suit your particular model of router. You can enter in your current IOS version and then the desired version in the 2nd column. It will show you every feature that is gained and lost if you moved to the 2nd IOS version. I usually just enter the lastest 12.4T release available with the same feature set to start with, as it is a no cost upgrade. If you want to achieve something that is in a larger feature set, you will need to talk to your cisco reseller about upgrade costs. Each IOS version also lets you know how much RAM and Flash is required to run it sucessfully, so make sure you know how much you have installed in your router before you start the upgrade process. Show Flash: will list the current contents of your flash memory including the exact spelling of your IOS version. Show version will show you how much ram and flash you have installed.