The internal components of the router are where the real magic takes place. Think of a Cisco router are being really no more than a specialized computer running a custom operating system. In this case, it is a computer optimized to provide routing and related functions. Instead of relying on a hard disk for storage, a Cisco router relies on different types of memory, each with a different purpose. In this section we’ll take a look at each of these different storage areas, and the functions they are responsible for.
There are four main memory areas within a Cisco router that you’ll need to be familiar with – Flash, RAM, ROM, and NVRAM.