The Cisco IOS is the proprietary kernel that provides routing, switching, internetworking, and telecommunication features. Here are a few of the features that the Cisco router IOS is responsible for:
- Scalability for network growth
- Security to control access or to stop unauthorized personnel
- Providing network protocols and its functions
- Connecting network resources
Each IOS is specific to the series of router or switch you are using. What exactly do I mean by that? Well, let's look at some routers and what IOS they are using:
You can now see that it is important that the IOS matches the series of router or switch you're purchasing. You cannot put a 2,900 series router IOS in a 1,800 series router; it just won't work. This is not like purchasing a PC, in which you can put pretty much any Windows operating system you want if it meets the hardware requirements...