Dissecting the internal components of a Cisco router

- When dealing with Cisco routers and switches,…understanding the inter-working of your networking devices…will help you better understand what is going on…when trouble comes knocking at your door.…Routers and switches are very similar to PCs.…They are just Task-Specific Computers.…They have a different objective,…but they are very similar how they operate.…In a device, you have many types of memory.…

RAM, or random-access memory.…ROM, or read-only memory.…RAM is volatile, meaning when the device reboots,…the RAM is clear.…ROM, on the other hand, is non-volatile.…Critical start-up instructions and hardware tests…are stored in ROM.…The bootstrap is stored in the microcode of ROM.…It is used to bring up the router and locate the IOS.…

The POST, or power-on self-test,…is also stored in ROM.…On start-up, the device runs through a series…of hardware functionality checks…to verify that the hardware is operating as expected.…Also stored in ROM is the ROM monitor,…which is used for testing and troubleshooting.…The last tool stored in ROM is the mini IOS.…