The IOS is among one of the most essential parts of the router, without it the router is pretty much worthless. Simply bear in mind that it is not essential to have a flash card (as defined over with the 1600 collection router) in order to pack the IOS. You can in fact set up most routers to pack the photo off a network tftp server or from an additional router which might hold multiple IOS images for various routers, in which case it will certainly have a big capacity Flash card to keep these pictures Cisco IOSV free. The ROM is utilized to begin and keep the router. It has some code, like the Bootstrap and MESSAGE, which helps the router do some standard examinations and also bootup when it's powered on or reloaded. You can not modify any of the code in this memory as it has been set from the manufacturing facility and is Read Only.   Visit https://dynamips.store/product/gns3-full-pack-images/